Don't shout me down too bad. After numerous delays, FINALLY got new (delphi) pump installed. Truck has been sitting since May.

Still no pump (To clarify, by 'no pump' pump doesn't cycle on at all)

How many volts should be at the pump and which wire(s)? Right now I have 12 at the relay, and 8 to the center wire on the pump. (swapping relays gives the same readings).

Honestly, I don't know what I'm looking at, what should I be looking for?

Anyone? Thanks.

Found THIS POST by Poorboy from 4 yrs ago. In his instance it was a bad wire supplying power to the relays.

Still open to suggestions.

If you have 8v at the pump you have a wiring issue. I would expect to see no more than .3V difference, especially if you are measuring at the pump with it unplugged from the pump.

I've been having a couple of other electrical related issues with the truck for the past year. With this latest issue, I'm wondering if they're all related somehow (bad wire, bad ground, etc)

Mice?

I don't know enough about the Dak's to say that there is an inherent issue. I know some FWD's had a problem with battery out gassing corroding a wiring bundle, but I can't say about the Dakota.

You might try looking at the wire harness that runs along the left fender, if i remember correctly its the main harness and think it goes to the engine computer. Water runs down between the fender and hood and soaks the harness and corrodes the wires under the cloth covering and tape. I found out the hard way after thinking the engine computer was bad when I had a no start problem, replaced the computer and no fix, did some more digging and unwrapped the harness to find a mess of corrosion hiding inside, did some wire repairs and all was good after that. This was on a '93 V8 Dakota.

^^^Worth checking out. A friend had some electrical issues on his '96 3500 Ram van. He found the problem under/near the battery.

The pump will only come on enough to prime the system(key on) then shut off. After the engine starts it will come on again. With this in mind how are you testing?

for testing purposes, run a jumper wire across the relay to keep the circuit hot all the time, then start with your testing. Follow the circuit from the relay down to the pump testing voltage every couple feet of wire and at all junctions. Find where the voltage drop is and you will find your problem.

probably the harness in the pic near the battery, very common problem on those and the voltage gets cut down dramatically or gone all together going through the corrosion. Very carefully open it with a very sharp razor, find the bad splice and fix it, not nearly as hard as you would think.

yep^^^ If I remember correctly there's a splice under the washer bucket that gets corroded and fails

run a jumper wire directly from the battery to the pump to see if the pump will run that way,might be a bad pump?

I remember Spirits and Acclaims from this time period had a major harness junction right next to the battery that was bad for corroding. I'm running an Optima red top sealed battery.

I'm working alone, so, when I'm checking things at the pump, I'm turning the key 'on' then going back and taking readings. I would jump the pump, but I don't want to blindly start applying 12v to the pins looking for the 'right one'.

I tried swapping relays around to no avail.

The other issues I've been having is the IAC and the overdrive. Last year the IAC went out, replaced it with a parts house one and couldn't get it to run right. At the suggestions of someone, I bought a factory replacement which was much better, but still not what it used to be. For the most part it would run good, but every now and then, no rhyme or reason, it wouldn't idle or it would idle just above a stall. Didn't matter if the truck was hot or cold, or if it was hot or cold outside. Also didn't matter how long the truck had been on. Turn the truck off, wait a few moments, restart it, then it was fine again. With the overdrive, just like with the IAC, no rhyme or reason, it would turn 'off'. REAL cute when bombing down the freeway! Eventually, I would also find it off right at first fire of the day. Pull the fuse, plug it back in, it was fine again until the next episode. Please realize, the fuse isn't blown, I'm simply unplugging it and plugging it back in.



It may be a few days until I get back over to the truck to start checking things. I will report my findings. Thanks for the input so far!

I would definitely start with the wire connection under the battery. You Texas guys are lucky, it takes a lot longer for the corrosion to set in then it does up here in road salt land.

The connection is pretty lame from Dodge. There are 3 or 4 small wires that enter one side of the connector, and 3 or 4 small diameter wires that come out of the connector. Then they wrap it with tape and put it under the battery where the corrosion is probably the worst. Those wires at that one splice are the 12 volt feed to nearly everything that gets battery power. If you have more then 5 volts, but less the 12 volts, that connection is probably bad.

For the test, at that one connection you had 8 volts, you can provide 12 volts to what that terminal connects to and see if the pump runs. If the pump runs, the wire connection is corroded. Anything 5 volts or less is powered by the computer, you DO NOT want to supply those connections with 12 volts.

For the record, that wire nut patch on the 93 Dakota 4x4 wiring outlasted the truck frame by more then a year. Gene

What we lack in road salt, we more than make up for with Gulf Coast salt.......

Sitting here reading poorboy's reply got me thinking about the truck having been hit on the drivers front (previous owner). I doubt it has anything to do with it since I've owned the truck almost 6 yrs, but.........

If my truck wasn't 12 miles away, I'd be checking things right now!

and when checking plugs for corrosion, especially ones under or near the battery, look close at the wire itself before the end terminal.
those wires can [and will] turn "green" from the battery outgassing, and although the terminals look clean, the wires can turn green under the insulation.
if you don't look very close, you can miss that. i have rewired many vehicles over the years [of all makes] that have had happen with wire bundles located around the battery.

Had a few minutes after work, went and looked at a few things tonight. Just looked, didn't troubleshoot

The underside of the relay holder looks shiny and new.



I also pulled the plug to the computer. All the pins look like they have a 'waxy' coating on them, some more than others. Normal? (crappy pic, I know).





I did find something odd, if not confusing. Not one of the ground wires going to the drivers fender was tight. The screws were tight, but in a cross threaded kinda way, leaving the wire loose. 2 of the terminals had no witness marks from the screw. I find it hard to believe this thing has been running around for 28 yrs with half its grounds not connected,

I'm wondering if the computer did finally die partly due to the lack of proper grounding?

I could see where the bad grounds could cause a problem, and cause all sorts of strange things to happen, but given the number of times I personally have seen the wire connection under the battery fail, I wouldn't make another move with unwrapping the bundle of wires and check the connections.

At this point, I'm 3 out of 5 Dakotas (90-96) that have had a bad connection. The other two I pulled apart and checked. When you locate that connector with 5 or 6 wires connected to it (some are pink wires, some are blue wires), give each wire a good tug. If its good, nothing will happen, if its bad, the wire will break. Those wires at that connection are 22 gauge wires, you can not break a good 22 gauge wire with your hands (or pull them out of a good crimp connector) each wires would start to cut through your skin and still not break. Gene

I know you said you have 8V at the pump but where are you taking the ground from on the meter? I have 20ft lead I use to ground straight to the battery and if the voltage comes out OK I check with the meter at the fuel pump ground. Trucks in particular have problems with bad grounds near the pump since they are often exposed to harsher environments.

Does it have a security system/light?

I worked on a Dakota that randomly would trip the security system and the fuel pump wouldn't fire up.

Not saying it's the problem but when I have a no start on anything newer than 1980 I start with the security light and see if it thinks it is stopping a theft. BMW's disable the ignition, some cars will disable the fuel pump. My wife's new compass disables the starter.

You can have what I call errant voltage. You unplug the device and get a voltage reading which can be low due to the problem. When the device is plugged in the voltage disappears. You need to probe while it is connected and trying to drive the device. In this case the fuel pump. That is a simple truck to diagnose and repair.