View Full Version : 94 Dakota 3.9L WON'T START/ No Power To Fuel Pump...


JeepHammer
04-16-2008, 09:06 PM
Cranks, but won't start.
No fuel pressure.

Checked/Replaced Automatic Shut Down and Fuel Pump Relay with known good.
Checked factory relays and they checked out fine.

Can't find a fuel pump fuse location in the Haynes manual.
I don't have an owners manual and would appreciate help finding out if fuel pump fuse exists, and if so, where it's located on '94 with MPI.

Pump is 2 year old Bosch/Mopar that works fine when hot wired.
New, known good pump wouldn't work when connected to wiring harness.

Fuel pump connector is in good shape, no corrosion.
When multi-meter is hooked to pump power wires, reads open circuit.
When key is turned 'ON', I get closed circuit, but no voltage reading.
Very good at using multi-meter and diagnosing electrical problems, but can't find a good schematic for this vehicle...
Haven't even found the positive source wire origin for the fuel pump in the Haynes manual...

Can anyone tell me what else/ where else to check and what else might cause this problems.
This is my dad's truck and he's driving me nuts to get it back on the road!

jlbritt1
04-16-2008, 11:40 PM
Try checking the wiring diagram in this post http://www.dodgeforum.com/m_546492/tm.htmthere's also a pic of the fuse blocks, a list of which fuses are which, and a parts list. Sounds like your problem may be ignition switch related, not sure rally without being there, but if you can wire around just the switch and get power to the pump it could be the problem.

dodgerules86
04-17-2008, 12:14 AM
Take out the ASD and Fuel Pump relays and test for constant voltage to the relay (30 is always supposed to be hot, I think). They had problems with a splice that powered both of those relays, it would corrode and thus, not provide good power.
The wiring in 1990 was differant than (1992 and above??) your 1994, becausein the newer years, theyadded the (very nice) Power Distribution Center (the black fuse/relay box), instead of having fuseable links and relays out in the open.
Check for good power first. If it has power, wiggle the wire bundle and see if it loses power (or, if it doesn't have power, if it"gains" power). Also do this for the switched circuit (which comes from the ignition).

codydakota
04-17-2008, 01:22 AM
sounds like the fusible link by the relay center under the hood, it's notorious for going out.

JeepHammer
04-17-2008, 11:31 AM
We Have A Winner!

DodgeRules86 is the winner!
Went poking around the archives after I posted, and found out that '93, '94, '95 have a splice in the bundle that runs under the relay/master fuse center beside the battery...

Right where a ground wire comes out of the harness, there is a splice, 3 into 1, and it was a total loss! Completely copper oxide and corrosion.
It took two butt connectors, about 2" of 14 Ga. wire and it works just like new!

Thanks guys, I appricate the direction!
I was REALLY dreading trying to locate and map the wiring harness on my own!

lghtngblt02
04-17-2008, 01:19 PM
Yep, its a common occurence. :DGlad you got it fixed. I think just about everyone with a first gen dakota has had this happen.