Fuel pump electrical issue

cdretc · #1 10-10-2006, 09:21 PM

My sweet truck is dying. I have a 93 Dakota 5.2 4x4 and last week it died on me. I was going to parts store (for wife's car) and near the store it started losing power and then just stalled. I could not start it up again. So I towed it home. I found out that I have spark, but no fuel. I changed the fuel filter and still no fuel. So I removed the fuel pump, I hooked it directly to the battery and it worked! So I went back and checked that the pump does not get electricity. I can hear 3 relays pulling in when I turn the ignition on (the auto-shutoff, fuel pump and another one?). From what I see on diagrams, the pump is powered from the PCM, through the auto-shutoff relay and then the fuel pump relay. I can't figure out the problem. Any suggestions? I also see on the diagram (from the Haynes manual) some points, like K51, A21, A14. Any ideas what these are? Maybe points where the circuit can be tested?

Any ideas/suggestions would be appreciated. Thanks

dodgerules86 · #2 10-11-2006, 05:25 AM

Have you tried putting another relay in place of the fuel pump relay?

cdretc · #3 10-11-2006, 05:28 AM

I tried switching them around. But also I hear that they pull in...

dodgerules86 · #4 10-11-2006, 05:43 AM

Quote:

ORIGINAL: cdretc

I tried switching them around. But also I hear that they pull in...

Pull in?

cdretc · #5 10-11-2006, 02:02 PM

Pull in = making the new circuit. I can hear that they click...

dodgerules86 · #6 10-12-2006, 05:03 AM

Well, you said you can hear the relay "click". So, that means that it should be working. However, test the following:
On the relay itself, it will tell you what tab is what.
Conditions: battery connected, key OFF.
Test for battery voltage at terminal 30. There should be voltage.
Turn the key ON. There should now be voltage at terminal 86.
When the key is turned ON, terminal 86 should provide a ground path for a few seconds.
Termainl 87A is connected to terminal 30 when the relay is de-energized (key off and/or PCM not providing a ground path).
Terminal 87 is connected to terminal 30 when they relay is energized (key ON and PCM providing a ground path).

So, test to make sure those are true. Unfortunatly, I can't really give you a location, but somewhere there is another connector. You will want to make sure voltage to the pump is making its way thru there.

1yamman350 · #7 10-12-2006, 08:16 PM

im having similar problems with my 93. would it be possible for u to scan the wiring diagrams from the haynes manual and post them? that would be awesome and good luck.

cdretc · #8 10-13-2006, 05:24 AM

Sorry can't do. It's copyrighted. But I know that the dealer has the same drawings and they usually give it to me... Sorry.

cdretc · #9 10-13-2006, 05:25 AM

Thanks 86. I'll try that as soon as the lady dies again. It was running fine today... It's a bizarre problem...

jragiles · #10 10-14-2006, 10:17 PM

Hello,

I've had a similar issue with my 94; my thread might have some info that you haven't come across yet....Good Luck!

J