Hello, I have a 92 dakota that has a 3.9l swapped into it. This thing used to run great. Lots of power and no issues what so ever. Now sometimes its a pain to start, will start then stall, and every now n then it backfires, and if I let it run for a lil while it will devlop a rough idle. I changed the cap,rotor,wires,plugs,air filter,fuel filter, cleaned the throttle body, cleaned and checked the egr system, gone over the wiring with a multi meter and a visual inspections, and replaced a couple vacuum lines that looked shady and triple checked the routing. I also then regapped the plugs I just put in to make sure I didnt screw that up. But it still does it.

Any Ideas?

The only thing I can think of are that stupid hall effect pickup or the fuel pump is crapping out. But maybe someone else knows before I go buy parts.

Thanks

First things first:
You made sure the spark plugs have a .035 inch (.89mm) gap, I hope, if you verified and/or changed that as needed before putting them in, there's no need to pull 'em out to check.
However, DO double check to make sure the plug wires are routed properly (refer to the good ol' paint drawing picture given) (I made this mistake, I swear I double checked to make sure each wire was going to the right plug, but, I was wrong) (while your at it, also double check the rotor and cap)
Also maybe check for error codes (http://www.dodgeforum.com/m_63384/tm.htm).
Other than that, I could only suggest vaccum lines (which you said you were careful when you replaced, and double checked) or bad fuel (I don't know, maybe?)
Of course, I am not that experianced with cars.
*As far as the fuel pump crapping out, you can find a fuel pressure gauge to hook up, and watch that*

local://upfiles/948/AAC90A30E3CA4D1A9E1360011D2213E9.gif
*hope your cylinders don't look like they do in the pic, lol*

Well today I figured it out. It was the hall effect sensor under the dist. cap. Nice. But its all better now.

Ok well I thought it was fixed. When I first start it when its cold, it fires right up and runs perfect for a little while then it starts to stumble and backfire out the exhaust. If I try to give it more air to keep it running it wants to shut off and start backfiring out the trottle body. Lack of fuel? Maybe my fuel pump is crapping out? Any suggestions? I am at a loss. It will restart after it starts doing this but it will still backfire and run like total crap. If I try to move it, it just dies. No check engine light has come on so far and I have tried to pull codes and all I get is a bettery has been dissconnected recently and a 55 which I believe is end of codes.

Have you checked the timing?????That could be the problem.

Timing is dead on, I thought the same thing. Thanks for the input tho. I pulled the plugs again. They were covered in gas. I'm wondering about the vacuum lines. Anyone with a diagram handy? The one under the hood is for a 2.5l not the 3.9l thats in it.

Hello. I am still looking for that diagram if someone has it handy. I have a 94 3.9l v6 in my 92 dakota. Ive got so many people completely baffled with this thing. But at least I have it the point now where it runs for a lil bit then it just shuts off like someone turned the key off or...it spits sputters and stumbles itself to death. Nice.

So far I have changed plugs..wires..cap..rotor...crank sensor...map sensor..tps...iac....coolant sensor.... hall effect sensor(the one under the dist. cap). Fuel pressure is fine according to Mr. Mechanic and I have ripped the wiring completely apart and checked for shorts...bad connections etc.... had it hooked up to a diagnostic monitor and got alot of crazy erratic readings but no codes.......set the #1 cylinder at tdc on compression stroke and checked to make sure rotor lined up with it to fire and it does. I checked and rechecked all the plug gaps. The only thing that we got out of the diagnostic reader that my mechanic had was that the auto shutdown is killing it and he told me to just start replacing stuff to see what fixes it.....nice advice. So I got a second opinion...same thing. excellent!

So my guess is still with the vacuum lines or buy a computer. I had checked the vacuum lines before only to realize that the diagram under my hood is for the 2.5l engine that came in the truck...not the 3.9 thats in it now. So now they are pretty messed up. Some are still hooked up..others arent, I have been trying to trial and error this but its not working. Anyone have any other ideas it would be cool to let me know and it would be hellacool to get my eyes on a vacuum diagram. help would greatly be appreciated.

Thanks
Eric

The following vaccum diagram is from a 1996 Dakota with the 3.9L.

local://upfiles/948/85572CFDA8704A339C525A3B7AC3B523.jpg

Thank you....that is awesome. It looks about the same except the egr stuff is missing which is fine since the egr is gone on my truck and I have a set of exhaust manifolds that came off a 99 without the egr port on the passenger side milled out. But this is perfect. Thanks again.

I,m not sure about the 3.9 but on the 5.2 this sounds like it could be the plenum gasket.I had 2 318's that did this and that was what it was.

Upon your reply, I pulled the intake off the truck. While I was removing it I noticed that an o-ring was missing from one of my fuel injectors. The intake to head gaskets seemed like they were sealed fairly well, although I didnt have to pry the intake off the truck. It just kind of lifted off. Some of the bolts werent all that tight either but its only supposed to be torqued to 12ft/lbs. I took the intake in to work and threw it in the parts cleaner and got all oil residue out of it. I havent had time to throw it back on yet. I hope to before the end of the weekend. I'll let yas know how I make out when its back on. But I'm not getting my hopes up.

I just did the head gaskets on my 89 3.9L and needed to pry the intake manifold up to break the seal.
12 ftlbs. sounds light if we are talking intake manifold bolts; they are 45 ftlbs on the 89 and I would think the same for a 92 (verified 45 ftlbs at the Automotive Repair Reference Center).
Regards,
Greg

As per my 1996 service manual (and the 2001 as well):
The plenum gasket pan (if removed) bolts will be tightened, in sequence, as follows
(1) Tighten to 2.7 N*m (24 in lbs)
(2) Tighten to 5.4 N*m (48 in lbs)
(3) Tighten to 9.5 N*m (84 in lbs)
(4) Verify all bolts are at 9.5 N*m (84 in lbs)

Throttle Body bolts:
23 N*m (200 in lbs)

Intake manifold bolts:
(1) Tighten bolts 1 and 2 to 8 N*m (72 in lbs). Tighten in alternating steps 1.4 N*m (12 in lbs) at a time.
(2) Tighten bolts 3 thru 12 in sequence, to 8 N*m (72 in lbs).
(3) Check all bolts are tightened to 8 N*m (72 in lbs).
(4) Tighten all bolts, in sequence, to 16 N*m (12 ft lbs).
(5) Check that all bolts are tightened to 16 N*m (12 ft lbs)

Generator mounting bolts:
41 N*m (30 ft lbs)

Adjusting Stap Bolt:
23 N*m (200 in lbs)

Conversions:
in lbs x 0.11298 = N*m
ft lbs x 1.3558 = N*m
N*m x 8.851 = in lbs
N*m x 0.7376 = ft lbs

I wonder if the differance could be in the fact that the Dakotas from 1992 on have multi-port fuel injection, instead of throttle body?
Note: the manual says, "Apply a small amount of engine oil to each fuel injector o-ring. This will help in fuel rail installation."

Hope what your doing finally helps your dakota!
Post back if you need more info, or, when the jobs done!

"I wonder if the differance could be in the fact that the Dakotas from 1992 on have multi-port fuel injection, instead of throttle body? "

Good point dodgerules86, I just checked the Automotive Repair Reference Center site again and they give your torque figures (and procedure) starting with the 94 year model, but allpar.com shows you to be spot on with move to MPFI in 92. [sm=icon_ladiesman.gif]

Glad you pointed that out!
Greg

It shows right on the intake mani that you should not go over 12 ft/lbs. I torqued things down to 15 so we will see. 12ft/lbs does just seem way to light for me also but......whatever mother mopar says I do. I did notice however that my injectors werent going all the way down into the ports when the fuel rails were bolted down. The o-rings were barely in the holes. So I removed the rails completely before installing. I altered the mounts to allow the injectors to sort of "pop" all the way into the manifold. I am wondering if this was my problem. I havent started it yet because I want to change the oil and I need to get antifreeze before I try to fire it up. I will be sure to let you guys know what happens.

Truck still no workie workie.......I am about ready to call chrysler and have one of their engineers come look at this thing....I am getting a lil preturbed. Well on the way now is a new distributor. Lets see what this does...........

You mentioned a mechanic talkin bout the auto shutdown circuit. Right?

I also have a 92 dakota, its a 5.2 but I'm sure the relays are the same. My 92 had a problem with stalling but not with backfiring at that time. It does currently but thats another story. ARG!

Anyway have you tried replacing the auto shutdown relay? You can test it real easy. Under your hood on driver side fender wall is a black box. Remove cover and you see black cubes. Flip lid over to get location of various relays. Take the relay from the ASD or Auto shutdown spot and move it to the starter relay spot. Put the starter relay in the ASD spot. Attempt to start your truck, if starter no work your ASD Relay went bad. New is approx $12 at NAPA or the like. If truck does turn over repeat test with Fuel pump relay.

The other cause of this is a bad engine controller (computer). Are you getting strange code 12's even though you've not disconnected your battery in over 50 starts? The next prob I had after a bad ASD relay was a PCM (engine computer) that had an intermittent short which caused the truck to not start (or die if it was running, idle or on freeway dont matter). When the truck wont start you will note that immediate after turning key to on (not start) the check engine light doesn't come on for its normal 4 seconds indicating the bulb aint burnt out. Until the check engine light returns on turning key to "ON" your truck wont start. When it DOES come back it will fire right up. This is a sign of a faulty PCM (Engine Controller, ECU, ECM whatever you want to call it parts store will know what you mean if you say engine computer).

I currently do have a backfire prob on mine. My engine computer went bad and so far I've had two remanufactured replacements in it and both make the truck backfire. No idea now if its a (second) bad reman computer or if something else got knocked out by my old computer. The truck ran fine on Friday but has backfired ever since I replaced original computer on Saturday morning. The old computer had the intermittent loss of power (code 12) problem. I actually think the original problem stems from the corroded solder joints in the wireharness along the firewall (three of them, blue, red (with stripes white or orange) and a black/gray group. 4 wires in each of the three clusters). The solder joints corrode and cuase a short. I think I let my problem go to long (didn't know what problem was for a while) and it knocked out the computer.

"I actually think the original problem stems from the corroded solder joints in the wireharness along the firewall "

I agree. However, I think I already asked him (erock92kota) if he checked all the wiring, and he said yes (I believe it was in another thread). But that is correct, they did have problems with corrosion on a few splices they did at the factory. (Typically, the splice that send power to the fuel pump relay and automatic shutdown relay). It would probably not hurt to take another look at all the wiring, and fix anything that looks remotely suspecious. I would recommend getting a voltmeter with a continuity tester. Test for things such as voltage drop (on powered wires) and continuity (on non powered wires).
Also make sure you test all grounds. Diconnect all the ground wires and clean the spots up (no dirt or corrosion, just clean metal on metal).

Yeah I also posted the 92 with 94 engine thread. I have replaced everything just about right down to every relay under the hood. I had the wire looms all apart and spent the better part of a sunday with a multi meter tracing wires, checking for shorts, broken wires, etc......I did find a few shady connections and some bad grounds but I fixed them...even the green corroded blob under the relay/breaker panel under the hood where the asd and all that jazz is located......the problem still persists.

So far I have replaced:

any relays I found
computer
air charge temp sensor
map sensor
coolant temp sensor
throttle position sensor
crank sensor
cap
rotor
hall effect sensor=distributor pickup
plug wires
plugs
pulled intake and gave it a thorough cleaning
made sure vacuum ports in intake were all free and clear
new intake gaskets
new o-rings on injectors and cleaned the injectors while they were out
modified fuel rail mounts so injectors were seated correctly
fuel filter
fuel lines
all vacuum hoses
checked and rechecked and rechecked vacuum plumbing
I have set the #1 cylinder at top dead center on the compression stroke and made sure distributor lines up (there are marks on the pickup to align with #1)
cleaned throttle body and made sure that all vacuum ports were clear
checked fuel pressure...holds at like 30ish when idling and a lil higher when I give it gas when its running for the minute it runs but it never dropped below 29psi

There are other things but I can't remember....I have done everytihng and a bit more then I can think of aside from replacing the actual distributor and pulling the front of the engine apart to check the timing there.

It will run like a champ for about a minute or so with some throttle hesitation....then it picks up a miss....then it starts to stumble and surge....then all of a sudden it either shuts down or if I try to save it, everytime I hit the gas it will die out and when I let off it tries to recover but normally results in backfiring either out the exhaust or out the throttle body. I have an open element air cleaner on it and I can hear the air getting sucked in thru the idle control like its trying to cut the air off to the engine. Like the valve is closing and allowing a smaller amount of air by. I havent replaced this part yet...but it is on my to do list in the near future. I would think that if the idle control was going bad I could still rev the engine and keep it running like I have done on other cars when they have gone bad.

ORIGINAL: erock92kota
I have an open element air cleaner on it and I can hear the air getting sucked in thru the idle control like its trying to cut the air off to the engine. Like the valve is closing and allowing a smaller amount of air by. I havent replaced this part yet...but it is on my to do list in the near future. I would think that if the idle control was going bad I could still rev the engine and keep it running like I have done on other cars when they have gone bad.


I never thought about that. Didn't you say that it would die if you drove it anyways? Or was it, as you were stopping it would die? (Or was that someone else?)
The idle air control (IAC) motor is controlled by the computer. There is a pintle on it, that moves in and out of the passage on the throttle body to let more or less air in. When they key is turned to the ON position, the PCM moves the pintle into position. Of course, "like I have done on other cars when they have gone bad. " << of course, you know how they work, I didn't need to type that [:@]:D

It dies no matter what I do whether its try to drive it or let it sit and idle. Mostly all I have done with it lately is let it sit and idle. I have tried to move it but that normally results in me getting it where I wanted by keeping the starter turning and moving it that way. Not good I know...but sometimes where it sits, it is in the way. But normally when I give it the gas pedal or work the throttle linkage, it seems to like smother itself out, when I release the throttle it tries to recover but typically just starts to spit and sputter and eventually die. Once in awhile it will recover, but not always. It is indeed undrivable by any means. Since it won't even run long enough to get it out of my driveway. I can hear like this high pitched hissing noise when it is trying recover which upon closer inspection I found to be the iac moving into the throttle body allowing less air through making said noise.

I have also been thinking about replacing the speed sensor....just for the hell of it...I have replaced almost everything else...might as well make them all new.

ORIGINAL: erock92kota
I have also been thinking about replacing the speed sensor....just for the hell of it...I have replaced almost everything else...might as well make them all new.

Hahaha... when I started reading the sentence, I was like "Why would de do that?" but than I got to, "just for the hell of it...I have replaced almost everything else...might as well make them all new."

Well I was out in the pool staring at the truck yet again. My lil girl walks up to it and pats its door and makes noises at it and gives it a kiss (shes gonna be two this weekend). She always loved to go for rides in the truck. I wish it would run for more then my own reasons.

So I got out of the pool and went into the garage and started performing inventory on parts I have left over from other projects. Mainly my turbo dodge days. I have sitting in my garage a 2.2l turbo engine that I have rebuilt. Everything is new. Stock but new. I also have a t-II setup but I would have to get creative with intercooler placement. I have a computer there but I need to check what all is needed as far as a harness goes. I think some things in the truck are the same. I have a shelby 2 piece intake manifold and the throttle body to go on it. A header with a turbo still bolted on. And some assorted other parts n pieces. I am thinking that if I do not get this 3.9l running soon, I am going to make a swap. I had thought about it before but never too seriously, and I brushed it off like oh it runs fine now why mess with it. But with its current record of almost two months not on the road.....its begining to bother me. It came with a 4 banger it might as well have one again. But one with a lil more oooomph.

If I rip this 3.9 out I will be more then happy to sell it.......I dont think anything internal is wrong with it. But it is making me angry at times and sometimes I actually loose sleep over it.

Well last night I woke up in the middle of the night and had a hunch to go try n turn the old truck over. When I flipped the key to the on position right before I hit start I listened to the fuel pump......

It made this odd noise I have never heard a fuel pump make before. So this weekend I am dropping the tank. Neither mechanic I had look at said it may be the fuel pump....actually they both told me its not. But I know that they shouldnt sound like the noise I heard last night. I will let yas know how I make out.

When you replace the fuel pump, that would be a great time to make sure all the gas lines are in good condition as well.

I replaced all of them except for the ones I couldn't get too that easily above the fuel tank. I will replace them too. while I have the bed off. Also I am gonna swap the shocks while I have a clear shot at the bolts in the cross member there on the frame. They are kind of a bugger to get at with the bed on.

Well I have the bed off the truck. The pump is fine. It was just getting low on gas. Took gas cans and filled the tank about half way this morning. Still does it. But.......I made a more accurate fuel pressure guage (I was using an old h.v.a.c. guage set that isnt very accurate but I thought would give me a ballpark number) with parts I scarfed up before I left work yesterday.

When the truck starts to act up, the fuel pressure goes up above 40. The book says after I read the right section that it should be between 36 to 45 psi. So I guess that its in order.

Go to Napaonline.com, and use Napa P/N 219657. It came up for a 1992 Dakota. $50.
Fuel pressure regulator should be in tank, at least it is in my truck. (Of course, on my truck, the pressure regulator is integrated with the fuel pump, and cannot be replaced seperatly, a nic $300 unit [:@] Hope mine doesn't go out!)
BTW, in my manual, it says the pressure regulator output should be 49.2 +/- 5 PSI.

The o2 sensor is giving out like a .9 volts which I believe means that its rich.....way rich
Wow. That's correct, and nice 'n rich!

Hope you can find the cause of this headache.

Which book do you have? My Haynes manual says that it should be between 35psi to 45psi to be in check. But your book says 49+/- 5psi, On the 96 and up trucks it calls for 44 to 54 psi. I am beginning to wonder how accurate this book is. I mean I get it for all the specs and mainly the wiring diagrams but now n then they come in handy for other things.

My trucks got a 94 engine in it. I was testing pressure at the test port on the fuel rail. It seems to stay right around 40psi. According to this book, my fuel system is fine after I read all the print. The pump was making a funny noise but after I put some gas in the tank the noise went away. I did however pull the pump assembly out anyways and fixed my fuel guage problem. The lil tabs that slide up and down the scale on the sending unit weren't making contact. So at least my gas guage is fixed and I got my new shocks on the rear.

I've got the factory service manual for 1996.

I was wondering about one other thing today. The little piece of tin. I believe its the interuptor for the distributor pickup. Is the position of that gap important. When I pulled my distributor apart, the interuptor was moving around a lil bit. I used a lil rtv silicone to hold it down but it is possible I didnt position it dead on where its supposed to be. I cant seem to find just this part anywhere. You have to buy the whole distributor around here. All you have to do to get this piece off is pull the distibutor, drive a pin out and it slides right off the shaft. I am just wondering if this is the problem or not.

I came across your thread this morning looking for answers. I have a 92 Dak V6 2wd. When I read your thread it sounded almost identical to the problem I have been having. 2 weeks ago mine started to intermittently run really rough and backfire at low rpm with no power. It would run fine above 2000 rpm under no load when I could get it up there. I spent last weekend going through it but could not come up with any thing. I have recently replaced the plugs, plug wires distributer cap and rotor as well as the ECM & coil when the fuel consumtion suddenly dropped from 19 mpg to 12 mpg. This did not fix the problem. I took the ECM back to the auto parts store for them to test and they said there was no way of testing it, but they have had quite a few problems with them and as it had a lifetime warranty they gave me new one. No luck, it made no difference. This morning I was about to go down the route you have been down and that was to start replacing things in a process of elimination. After reading your thread I was ready to give up!! [:@] Any way I had borrowed a high end scanner and decided I would use it to go through the whole thing. Quite a fancy piece of electronics. It could test all the relays and solonoids without removing them. I spent several hours today putting it through a barrage of tests. It also has a graphing function on it that helped me narrow down the problem. What I found was the timing was running at about 10 deg at idle and all of a sudden it would get rough and move up to 25 deg and some times to 45 deg and then cut out. The graph showed the timing to be very erratic. Any way, using the trouble shooting option on the scanner it pointed to the crankshaft sensor. It said to check the flywheel for damage or dirt as this would cause the sensor to give errors. I removed the sensor which was filthy and replaced it and it solved the problem. :D The timing graph is nice and smooth now with clear cut changes at rpm changes. By the way the scanner had the following specs for the fuel system. I checked these on mine and they were within these parameters. Fuel system pressure with vacum hose to fuel pressure regulator disconnected - 39.0 - 41.0 psi. With vacum hose connected - 31.0 psi. Fuel pump pressure 75 psi. Not sure if any of this will help at all, but thanks for all the posts it sure helped me. I know you have changed the crank sensor on yours but you may want to check for dirt or damage to your flywheel. Does yours run rough all the time or is it intermittent?

I have a brand new crank sensor on the way. The last one I got from a junk yard off a good running truck. The owner is a friend of my uncles so I didnt pay anything for it. Other then that everything else I have bought was brand new.

It runs rough all the time I guess. It starts up fine when it's cold and runs beautiful for a min or so. Then it dies off. It doesnt even run long enough to get it out of the drive way. I think I will have a look see at the flywheel tho. I am running out of options. I really need to get this truck runnin one way or another.

I'm glad this helped someone thoough.

ORIGINAL: erock92kota

I was wondering about one other thing today. The little piece of tin. I believe its the interuptor for the distributor pickup. Is the position of that gap important. When I pulled my distributor apart, the interuptor was moving around a lil bit. I used a lil rtv silicone to hold it down but it is possible I didnt position it dead on where its supposed to be. I cant seem to find just this part anywhere. You have to buy the whole distributor around here. All you have to do to get this piece off is pull the distibutor, drive a pin out and it slides right off the shaft. I am just wondering if this is the problem or not.

I would think pretty important to your timing as they determine when the the hall effect switch turns on and I imagine this occurs at a certain cam position. If they are off some maybe the controller tries to adjust the timing and loses all signal from the distributor which should cause shutdown.

That kind of what I have been thinking. I think I'll just find a distributor and throw that on too.

Brand new crank sensor. Idled for approximately 20 mins. Then I gave it gas......it died. Started back up.......same deal. Give it gas and she dies after a couple mins. I'm buying a new distributor for it. Hopefully soon. It definitly seems like a timing thing and I just wonder about that interuptor in the dist. not being in exactly the right spot.

i had almost the same problem u have with my 94 3.9L what i did was i ask my mechanic about it and what he did is he went into the comp and reset it then raised the RPM amout so instead of the truck idleing around 150-300 it now idles at around 600

Brand spankin new distributor and timing chain now.....still no workie workie. Pulled the plugs again last night. They are covered in black soot. To much gas........? Pulled the 02 sensor, Its all covered too. Would the oxygen sensor send a signal to the puter to keep dumping fuel if its covered in soot or not reading properly causing my truck to die? When I unhook the one vacuum line and let more air in the intake it runs a lil better but not 100 percent. Still dies eventually. I hit the gas while its running and it hesitates then rpms go up. I cleaned the o2 sensor all up today and I am gonna throw it back in tonight. I guess we will see what happens.

Well tonight for ****s n giggles I ripped the front off my engine. Guess what I found????? The timing chain has about 7 degrees of play in it. Nice.

All this time........a lesson learned. Just because you set the damper at top dead center on number one, then line up the distributor to number one, doesnt mean the timing is always dead on.

I would indeed like to thank everyone for all their responses. They have been helpful in making me think about things that may be wrong. During this endeavor I have learned so much about these engines that I almost feel like I designed it myself.

Tomorrow I am going to the parts store after work af picking myself up a new timing chain set and slappin that in there. Im guessing that this will fix the problem. There is only supposed to be about an 1/8th inch of play at most and well 7 degrees.....thats about an inch.

I wish I would of followed my gut in the first place and saved myself a bundle of money. I have never been the greatest troubleshooter but all the neato tools I have picked up and the new dakota wing in my brain make it worth while.

At least now I shouldnt have any trouble with it for a while [sm=headbang.gif]....knock on wood...short lil prayer.....

Almost everyting under the hood is new aside from major engine componets.

No I never did go buy a new speed distance sensor.....but I really thought about it.

Well I look forward to talking to all of you in the future on here.

Thanks a bunch,
Eric

Eric,
Thanks for keeping us up to date on this repair. It has been a very informative thread.
Regards,
Greg

Let us know how the installation of the new timing chain goes, but glad to hear you finally found the problem!
I've got some projects of my own: valve cover gaskets, starter, master cylinder and brake booster, and (found this out a few hours ago) A/C compressor (having no A/C is not fun).

Well I replaced the timing chain today after work. I just got done buttoning the engine back together about 45 mins ago. I didnt think it was too bad. Roughly 7 hours to swap a timing chain. But it still seems to be dumping way too much gas into the engine. It hesitates something feirce when I blip the throttle after shes warmed up. Then it flooded itself out.

I pulled the dist. cap off to see if the mark and the rotor will still aligned at #1tdc.

Check.

Pull plugs, give them a cleaning, regap, pop them back in.

Check.

Let it sit for a bit, turned the key, vroom she fired back up. So I let it run long enough to get warm and topped off the cooling system. Turned it off and changed the oil and oil filter. Checked the tire pressures. Got back in and started it up. Backed it out of the driveway. I managed to get about an 1/8 of a mile up the road and it started to buck, sputter, choke, and damn near died on me. It was all I could do to get it turned around and heading for home. Then I couldnt even get it up into second gear because when I would push the go pedal down she would buck and sputter. Felt more like a rodeo ride then a cruise in the ol' kota. But that first few moments of pulling out of the drive way all the way up to third gear it felt great again.

So I think tomorrow I will go get a new o2 sensor. I think the black sooty substance I tried to clean off the one in there now may have ruined it. My buddy tried to tell me you can clean them and then demonstrated this with some brake parts cleaner, a lil kerosene, and a torch........I think it may be ruined. I was just gonna try to blow it off with some comressed air.

I do however have a question about the throttle sensor I replaced. Were the 94 throttle sensors the same as 92. I was going through my reciepts and noticed that I bought a 92 throttle sensor and not a 94. The engine in my truck is a 94. Just my curiosity. I guess I could do a lil research and answer that question for myself.

Hey guess what.....they are different. [sm=bomb.gif]At least they have different part numbers at a couple of different auto parts stores online. Ill be picking up one of those tomorrow too. But this time I'll be sure to get the right one.

Got the correct throttle sensor. That made a small difference.......It ran but....it was terrible. Anything over an idle and it would break up horribly.

I pulled the wire off the dist. cap for the coil. The terminal was corroded. How does this happen from sitting for a couple months? So I pulled a couple of the spark plug wires off the dist. and they were worse yet.

Made a trip to the parts store. Bought a new set of wires. Got home and pulled the cap off to clean the terminals. The terminal for the coil spun around while I was buffin it with some sand paper. So this made me take it over to the work bench where I hit it with my multi meter. Sure enough......when I push in on the bottom of the coil terminal that rides on the rotor it breaks the connection. As I wiggle it in and out it breaks and makes the connection. Hmmmmmmm........

So I went and bought a cap to replace my brand new cap. Put the wires on. Started the truck.

Then I drove it up the road and back. Then I took if for the hour and a half round trip to my parents house and she ran like a top the whole way. The engine ran smoother then I ever remember and it seems a little more snappy then before in the passing lane. But I think after that I can safely say that this truck is cured.

congrates

[sm=happy046.gif] well done!
Regards,
Greg

Erock, your truck still running good?

Yeppers

She runs like a champ. Two weeks and no problems. Hope I didnt just jinx it.

Well I did have one little issue the other day. But I know now that I need to get to a boneyard and get a new plug for the tps in my harness. But other then that its been all good.

I just finished up a sound system in it today. A pioneer head unit I had bought about a year ago, A set of Boston Acoustics componets in the front and 4x6 boston plates in the rear, a pioneer 6 disc cd changer, an 8" boston sub, and a 400 watt crossfire amp I had stored away in the garage. It still needs some tweeking but overall it sounds pretty good and should fulfill my audiophile side for now on those trips to and from work and wherever I may drive in it. It was a chore hiding everything and making certain things look as though they came in the truck, but for the most part I pulled it off beautifully.

Now I am planning on attacking a few body related ailments, a hole in a rocker panel, making some big driving lights look like they came from the factory in the front valance, and getting the last few stickers the previous owner put on it.

How bout you, ya get that a/c working yet?

Sound system sure sounds nice. Wish I knew something about them...

My A/C is still dead :(, I've been pretty busy lately with some training and work, so tommorow I'm gonna look into getting that fixed (I'll talk to some people down here, and contact his insurance company because I'm sure it was killed because of the accident, the timing is just too weird for it not to be). Other than that, replaced my starter, and she's running great.

Good to hear its runnin. I would look into the a/c thing.

I had a 92 cherokee, I rear ended some lady in rush hour traffic who didnt have any brake lights.

Her insurance company wrote me a check to get all the body work done and a new radiator and all that stuff. But the thing I swear never worked right afterwards.

In your case, if the condenser in front of the radiator took on some damage, it may have leaked out the freon and rendered your a/c useless. There is oil in the a/c system that serves as a lubricant for the pump. It normally runs through out the whole a/c system. If that leaked out.......smoked compressor indeed. So there is relevance to your case here since you did take on some front end damage and the condenser is right there. Your nose getting tweaked could have very well caused some issues with your a/c. Also with your truck being a 96, after awhile solder joints do get weaker, tubing sort of deteriorates. A jolt like that could have knocked a tube off or snapped something in the a/c system here towards the front of the truck.

Fortunately for you, I have a associates degree in h.v.a.c. I know these things. Just when I thought that degree would never come in handy other then not having to call a furnace guy in the middle of the night. I worked in the field for a year or so, I hated it.

Hope this helps, but other wise good to hear your truck is working. Its always a good thing.

Stereos arent that hard to figure out. I installed them professionally for a while. But theres not much of a market for it here so the place I worked closed up and since I am sort of rooted here now with a wife and a kid and a mortgage. Moving to find work in that area really isnt an option at this time.

They checked the refrigerant pressure (and, upon recieving the truck back and bringing it home, verified) and said it was OK. After the accident and all, even with the A/C turned "off" I could hear the clutch trying to engage sometimes (I'm assuming something up there is out-of-wack). I simply disconnected the connecter to the clutch, and it made the sound a few more times, and stopped. I also remembered they did not (at least appear to) do a front end alignment, which, I would think would be standard procedure on a front-end accident. So there are 2 things for me to bring up.

I've helped my friends replace head-units. The things that get me are amp's and some of the ratings and such. Oh well, I haven't actually touched and amp or helped put on in, and, I only learn good hands-on.

I cant believe they didnt even check the alignment. I think in your case I would of got another shops opinion. I'm not gonna say it but it would appear to me they were trying to keep some money on this one. I would at least be skeptical about it.

If I were in your shoes I would find it really odd that the a/c quit working roughly the same time as the accident. I would definitly push that issue.

Welp I must be off to work now.

Hope you can get this one straightened out.

have you tried a compression test ?

ORIGINAL: jim16050

have you tried a compression test ?

Whatcha talkin about exactly?

Yeah, a compression test was done. The truck has been running fine for quite some time now though.

My 92 D150 3.9L is doing much the same thing, however it does still run and is drivable. It backfires under load. This is with new plugs, cap, rotor, wires, timing chain and sprockets. It seems to me that the throttle sensor was the breakthrough for your problem. You then discovered a bad cap, but would you agree that the throttle sensor was the keystone to correcting your truck? I think I will try that next. I have also thought of replacing the crankshaft sensor because the timing mark jumps at idle speeds. I hate to think that I might be on the verge of taking the same trip you have been on just trying to get this thing fixed. Your posts may save me a lot of frustration. I certainly hope so!

Is the check engine light on or does it come on at all during any of this? Did you try the rolling the key trick to get codes out of the computer? I would check for vacuum leaks and look into your egr system. The egr valve may be stuck open. The computer controls the timing and uses inputs from various sensor to set it. It will appear to fluctuate a bit when idling. As long as you set the timing marks on the chain when you put it on correctly, and you didnt remove or turn the distributor...I would't worry about the timing.

I think part of my problem was the throttle sensor, but I know that it wasnt the whole problem. The main problem was a defective dist. cap that was recently replaced. Also my timing chain was way stretched out. I would read up on how to check sensors, perform tests on them and then replcae them as needed. My tps did have a dead spot in it. A dead spot in the tps would result in a dead spot in the throttle so it looses power at a certain position. I also had a bad connector in my harness that wasn't helping things either. I eventually replaced every sensor as well as the computer and learned alot during this whole ordeal. Of course my truck has over 200,000 miles on it so not everything was working as it should, but I strongly feel that if I would of just re-replaced the cap it would of ran.

One thing that really did help me out alot was referencing this page....www.allpar.com

There is alot of useful info for the do it yourselfer like you or I. Trouble codes, how to obtain them, and alot of if this is happening try that.

I hope this helps,
Eric

P.s.......the truck is still running beautifully. I haven't done a single thing to it since this except put about 4,500 miles on it and change the oil.

did you get the pcm for the new engine?it may not be compatible in some way with the old pcm...I hate electrical crap!

Ummm yeah. The truck has been running great.......... For awhile now.

Nutshell history: Bought truck 1 year ago w/100k miles. Ran great. Six months later muffler leak had gotten much worse and it began rough running. Replaced muffler, tailpipe and catalytic converter. Replaced sparkplugs, wires, cap & rotor. Noticed timing fluctuations. Error codes were #22 & #45. Replacedtemperature sensor(parts books give wrong p.n.-use the one listed for the 318), at a complete lost as to what to do about #45 - truck has 3 spd trans, error #45 is overdrive solenoid.
Compression check shows 140-160 psi on all six cylinders. Timing chain had massive amount of slack. Replaced it. Checked new spark plugs and they were fouled and wet with gas. Found vacuum leak on pass. side of intake and fixed it. Ran great for about ten minutes, then started backfiring. Read that fuel injector o-rings could be cause. Replaced them. Ran good for a short while. Now it is back to running rough and backfiring again. Seems that everything I do improves it for a little while, or at least until the next time it reaches operating temperature. Sat, when I posted, I called all five of the auto parts stores in town (think green acres here) and came up emptyhanded for the throttle position sensor, so I will try again Monday. I am somewhat curious as to why the oxygen sensor isn't going crazy with all of the raw gas on the spark plugs. The motor is doing what I would call fluttering when you give it the gas, like it is faulting in some way on all six cylinders, much too fast to be a miss on one cylinder. This is in addition to the backfiring when under load.

Well after reading this....my best guess would be the map sensor.

Sounds logical. I'm reading a Chilton's for this truck. It is almost helpful.

Found this item. Interesting. http://www.wellsmfgcorp.com/pdf/counterp_v6_i1_2002.pdf It addresses similar problem on 93 3.9L. I had discoveredslack in my rotor shaft and had asked a factory mechanic about it. He said that they had been taught that the gear should be replaced if the slack exceeds three degrees. I estimate my rotational slack to be more than that. However, the mechanic steered me away from doing that, suggesting that the problem was more likely to be electrical.

I had no more luck finding parts in stock today than Saturday. Auto Zone said that if I bring the old parts in, they can test them. That is great. No sense in replacing good parts.

The wife said I should ask you for all the parts that you took off, since most of them were probably still good!

HELP!! I was given a 1992 Dodge D-150 3.9 1/2 ton. I was told that all it needed was a fuel pump... Needless to say alot of other things have shown up. Apparently it sat for awhile. Once I finally could ante up for a fuel pump. then I started trying to eleminate the rough running and bucking. Keep in mind that I am a full time student with limited income. after the fuel pump I then changed the spark plugs, wires, distributor cap, rotor and cleaned the injectors and replaced the o-rings, Now my mechnic says that the o2 sensor needs to be replaced. thats $60. I can't afford now and I have no transport for school. I have limited tools and means, can any one give a lady a break? Did the throttle sensor do the trick?

I wasn't sure if you were asking me or erock92kota, so I hope neither of you will be offended if I jump in with my two cents worth.

You have gone down pretty much the same road as I except for the fuel pump. Of all of the things that I tried, replacing the throttle sensor was the least effective measure. Of course, if your unit is bad, it may make a major difference. Can you take it off and carry it to a parts dealer who has the tools to check it? Places like Auto Zone and Advance Auto may be able to help you. It is not hard to remove, but you will need the correct size torx driver.

My engine had 108,000 miles on it and the timing chain was stretched badly. Also the oil pump drive shaft and bushing were badly worn. Replacing those items made the biggest improvements of all of the changes that I made. Those items will require more than just the average skills and experience and require special tools. Remove the distributor cap and have someone turn the crankshaft back and forth. Watch to see how far the bottom pulley has to be turned before the rotor button starts to move. You can expect it to have about 5 degrees slack or more. Mine had about 15 degrees slack and was way overdue to be changed. Next, grasp the rotor button and twist it back and forth to check for rotational slack. Up to 3/16" movement is o.k.. Not ideal, but o.k.. Anymore than that and the oil pump/distributor shaft and bushing will need to be changed. If that is the case, your motor is probably backfiring alot. If it is not backfiring, those parts are probably o.k., but I read that your motor is bucking, so I suspect you may have this problem too.

My truck still isn't 100%,but itis much better. I'm thinking o2 sensor myself. It's $55 at Auto Zone. If your mechanic quoted you $60 parts and labor, that's a real deal - when you can afford it. That's cheaper than carrying it to the dealer and having them check it, plus when its done you have a new 02. I have read that it should be changed every 60,000 miles anyway.

Since my truck isn't a daily driver, I haven't felt the pressure to finish correcting it. I think it is about 95% right. It is very usable now, but I still need to work on it some more.

I have been where you are now with school expenses and all and I know it doesn't solve your problem to tell you this, but if you can get your truck running for four or five hundred dollars,
that is much less than it would cost to go buy a good running vehicle. Once it is running, you won't get good gas milage out of that vehicle, maybe 16 mpg, but that is still cheaper than a car payment.

Good luck.