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Fuel Pump Diagnosis '93 Dakota.......IT LIVES

Posted By: SattyNoCar

Fuel Pump Diagnosis '93 Dakota.......IT LIVES - 07/05/21 01:29 AM

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. help
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 02:18 AM


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.
Posted By: Sniper

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 03:12 AM

Originally Posted by Satilite73

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.
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 03:51 AM


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) work
Posted By: Sniper

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 03:53 AM

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.
Posted By: 383S_Fastback

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 04:30 AM

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.

Attached picture Harness arrow.jpg
Posted By: Fat_Mike

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 02:28 PM

Originally Posted by Sniper
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.


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

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 02:58 PM

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?
Posted By: mgoblue9798

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 03:56 PM

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.
Posted By: HotRodDave

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 05:12 PM

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.
Posted By: Dcuda69

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 05:24 PM

Originally Posted by HotRodDave
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
Posted By: rhad

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/05/21 09:12 PM

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?
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/06/21 12:06 AM


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.

confused

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! beer
Posted By: poorboy

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/06/21 12:59 AM

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
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/06/21 02:15 AM


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......... shruggy

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

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/06/21 04:26 PM

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.
beer
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/08/21 12:34 AM


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.

[Linked Image]

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).

[Linked Image]



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, shock

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

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/09/21 12:30 AM

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
Posted By: IMGTX

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/09/21 12:47 AM

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.
Posted By: NITROUSN

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/09/21 01:14 AM

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.
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/09/21 02:23 AM

Security system? It's a '93 Dakota, it's its own security system... laugh2 (I know what you meant, the thought of a security system on a '93 Dak made me chuckle). Back when I worked at a used car lot, I had to deal with no-start issues due to added on alarms. I appreciate the comment. Oh, I'm grounding to the chassis.

Can someone tell me how to properly hot wire the pump? It has five pins, the middle one is where I found 8 volts. How do I ground it?

I appreciate the comments and am taking notes. I won't be able to get back over to it until this weekend.


That is a simple truck to diagnose and repair. Sorry, unless its a system pretty basic like my wagon, electrical kicks my butt. I'm not scared of it, I just don't know how to correctly trouble shoot something with a computer. frowwn

[Linked Image]
Posted By: Dcuda69

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/09/21 02:54 AM

2 second Google search. Looks like the dark green/black wire should see 12 volts key on(2 second prime)/engine cranking.

https://easyautodiagnostics.com/chrysler/5.2L-5.9L/fuel-pump-circuit-diagram-1
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/09/21 04:02 AM

2 second Google search.

I must've used the wrong combination or something, because I did look before starting this thread, and didn't come across that.

beer

WAIT A MINUTE!!! According to the page you posted, the relay gets power from the fuse box from fuse 16. That is the same fuse that powers the OD switch, which I've been having problems with.

Coincidence? What does this tell you?
Posted By: moparx

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/09/21 06:11 PM

"everything is connected to everything else"...........coincidence ? hmmm...... work
or as my old man liked to say : "what a co-inky-dink".......... laugh2

you may have stumbled on to a solution to two problems. now to find out where the issue is presenting itself in the harness.
beer
Posted By: rhad

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/10/21 02:14 AM

when i was having trouble with my 92 dakota i spliced in a long wire to the hot wire at the fuelpump,then ran it up to the battery,touch the wire to the battery and you can hear the pump run
Posted By: Moparite

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/10/21 01:55 PM

Quote
WAIT A MINUTE!!! According to the page you posted, the relay gets power from the fuse box from fuse 16. That is the same fuse that powers the OD switch, which I've been having problems with.

Make sure you have constant power there before testing(after the fuse).
This is only to power the coil for the relay, After "jumping" it you need to make sure you have power at terminal "D" of the relay. This is what gives the pump power.
Posted By: poorboy

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/11/21 05:17 AM

When I field tested mine, I hooked 12 volts from the battery to the female terminal at the relay that feeds the fuel pump. It will either run, or it won't, it doesn't need power very long to determine if the problem is with the pump or not. Doing this eliminates everything between the battery and the pump except the immediate wire to the pump, the pump itself, and the pump ground wire. Once you determine which wire powers the pump, you can also power the pump right at the pump if need be, but you would also probably have to provide a ground for the pump as well.
If the pump runs when 12 volts is applied in place of the relay, then the issue is before the relay, probably the wire splice discussed before. Gene
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/12/21 01:43 AM


Finally got over there this afternoon. eyes

Was able to confirm a few things, but she's still not a runner.

Using starting fluid, she DOES run, albeit briefly.

I was able to figure out how to hotwire the pump and found BOTH pumps work. (Meh, not upset, I don't know when it was last replaced)

Where I had a voltage reading at the tank, was actually voltage for the fuel gauge.

Looking at the diagram Dcuda69 provided, I'm getting voltage everywhere I should be EXCEPT at the pump. At the pump I've got nothing. confused

And that's where I ran out of time. mad

I need to look more closely for the wires Gene is referring to. I don't have any wires that pass directly under the battery. I have a harness that passes in front of the battery that I thought was for the lights, horn, etc.
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/18/21 11:43 PM



Question:

If I jump the fuel pump at the relay (with the relay in) to make the pump run, should it start while hot wired like this?
Posted By: poorboy

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/19/21 01:56 AM

Originally Posted by Satilite73


Question:

If I jump the fuel pump at the relay (with the relay in) to make the pump run, should it start while hot wired like this?


Just a long shot, all the relays in the under the hood box use the same relays. Did you try swapping the fuel pump relay for a different one (like the one for the wipers for instance, one you know works)? Maybe you just have a bad relay?

An answer to your question: Yes, as long as the relay has 12 volts to it, and the wire that feeds the pump is good. Usually, its the wire that supplies the 12 volts to the relay that fails, but I've also seen the feed wire to the pump fail.

If you have 12 volts coming into the relay: Remove the relay, run a jumper wire (make one about 3" long with two male spade terminals on it). Put one end of the jumper wire into the slot for the 12 volt power supply on the relay, and put the other end into the [censored] that the wire goes back to the pump. You should be able to hear the pump run. If the pump runs, the truck should start. You can drive the truck that way, but you will need to disconnect the jumper wire to turn off the fuel pump. If the pump does not run (since we know its good), the wire is broken somewhere between the terminal and the fuel pump. If you are really fed up with the whole deal, you can get under the under hood fuse box, and find that wire that goes to the pump from the relay, and run a whole new wire back to the fuel pump.

If you do not have 12 volts to the relay: Your truck has the under hood fuse & relay panel, there is a bundle of wires that go into that box. Follow them down to where the bundle splits. From memory (we know how that works right?), the bad wire splice is in the bundle of wires that turns back towards the firewall, about 6" or so from the bundle split, towards the firewall. Some of the wire bundles are warped in the non-sticky friction tape, and some are in the black plastic wire loom stuff. You are going to have to undo what ever is covering the wires to find the splice. A sharp razer knife will cut through the tape, but be careful not to damage the wires in the process of cutting the tape. Usually unwrapping the friction tape is a royal pain. I usually just cut the tape with a slot running along the length of the wires and peal it off like a banana skin. Your local auto parts store should have a roll of Friction tape, the last roll I bought was under $5 and it goes a long ways. Once the wire repair is complete, you just wrap the wire bundle back up with the new friction tape.

Your issue has to be one of these two things, provided the wire connection at the pump is good.
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/19/21 02:13 AM


Thanks Gene for the input, greatly appreciated.

Now, the reason for my question.

With the pump jumped as I stated above, the pump is running, but the truck will not start. Just cranks. (yes fuel is getting to the rails)

BUT, whether the jump wire is hooked up or not, spray starting fluid down the TB, and it tries to start just on the starting fluid.

I unwrapped the harness from the relays back to under the washer bottle, all factory splices look good, no corrosion or loose wires. I don't want to redo all the factory splices at this point just for a slim maybe.

*sigh*
Posted By: Sniper

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/19/21 02:15 AM

Originally Posted by Satilite73

Thanks Gene for the input, greatly appreciated.

Now, the reason for my question.

With the pump jumped as I stated above, the pump is running, but the truck will not start. Just cranks. (yes fuel is getting to the rails)

BUT, whether the jump wire is hooked up or not, spray starting fluid down the TB, and it tries to start just on the starting fluid.

I unwrapped the harness from the relays back to under the washer bottle, all factory splices look good, no corrosion or loose wires. I don't want to redo all the factory splices at this point just for a slim maybe.

*sigh*


the injectors are fed a switched 12v, switched by a relay turned on when the key is in run. The computer will pulse the ground to fire the injectors. Back probe your injectors with the key in run and see if they are getting 12v. I am thinking the 12v that feeds the fuel pump relay is also the same 12v that feeds the injector relay.
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/19/21 02:37 AM


I am thinking the 12v that feeds the fuel pump relay is also the same 12v that feeds the injector relay.

You are correct. Fuel Injector Circuit

I will check that next trip over.
Posted By: NITROUSN

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/19/21 02:55 AM

Dude I feel sorry for you but it is a easy problem. Mouth shut so I do not hurt the sensitive.
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota....... - 07/19/21 03:08 AM

Originally Posted by NITROUSN
Dude I feel sorry for you but it is a easy problem. Mouth shut so I do not hurt the sensitive.


Send me a PM then. I'm trying to learn. You won't hurt my feelings.
Posted By: NITROUSN

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/19/21 02:01 PM

Here.

Attached picture relay.jpg
Posted By: rhad

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/22/21 02:14 AM

just use a noid light on the injectors,it will tell you if they are getting the juice and ground they need!!,auto parts store might have a set cheap,only need i noid for a test!!
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/22/21 03:35 AM


Truck is 11 miles away not here with me, so I can't just run out and try suggestions.

Next trip over I'm going to look more closely at the harness. In my frustration, I'm probably overlooking something right in front of my face.

As usual, I'll report my findings.

beer
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/25/21 04:20 AM


Well, I got it running, but I don't have it fixed. realmad

Unwrapped the harness the full length of the fender. Every factory splice I came across was free of corrosion and not broken.

I figured out that if I ground the blue with yellow tracer wire the pump comes on and the truck will start/turn off with the key (pump remains on though). If I disconnect this ground while its running, truck shuts off immediately. Looking at the diagram provided earlier, the blue with yellow goes back to the ASD relay then on to the ECM. I tried a different relay, with no difference.



(On a side note, this thing hasn't run since May, and it fired up immediately tonite. Kinda surprised me how quick it fired up)

Am I possibly looking at a bad ECM?

confused
Posted By: 4406bbl

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/25/21 01:32 PM

I have never work on gas motor trucks but the diesels fail the wire between the asd and the pcm...
It will test good with a light but cannot carry any load. I would load test from ecm pin 51 and C on the asd, and also load test at terminal A of the asd. You can make a load tester out of an old headlight and socket, one filament is about 4 amps, both filaments is about 9. Make sure it will light both coming from the ignition switch, jumper the control side of the asd, and test it at pin 51. To not spread misinformation, diesels almost never fail the blue/yellow, they fail the green/black, pin2 to the asd, and get that wonderful no start, no buss message. You need to load test, as I know a lot of diesel guys that now own 2 good pcm/ecm because they will not listen. I will add I had a friend that had a 93 Dakota brand new that would strand him all the time, no pump, dealer installed 2 fuel pumps, the fix was a new loom back to the pump, but I do not know all the exact details, maybe a hero tech cut it.
Posted By: Moparite

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/25/21 02:21 PM

Quote
the blue with yellow goes back to the ASD relay then on to the ECM.


If this is the case it is the ground to the coil side of the asd relay. The ECM will supply the ground for the asd to come on(ignition on no crank) but go off in a few seconds. It sounds like the ecm is not supplying the ground for the relay to come on. You need to check this with a meter! Put one lead on the positive battery terminal and the other on the blue/yellow wire lead. As soon as you turn the ignition to on you should see battery voltage.
Posted By: 4406bbl

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/25/21 02:32 PM

Originally Posted by Moparite
Quote
the blue with yellow goes back to the ASD relay then on to the ECM.


If this is the case it is the ground to the coil side of the asd relay. The ECM will supply the ground for the asd to come on(ignition on no crank) but go off in a few seconds. It sounds like the ecm is not supplying the ground for the relay to come on. You need to check this with a meter! Put one lead on the positive battery terminal and the other on the blue/yellow wire lead. As soon as you turn the ignition to on you should see battery voltage.


I get what you are trying to tell him but he should get 12volts from A of the asd, to ground, key on, and able to pass a load test. The blue and yellow must also be able to pass a load test , a meter is not good enough. If both of those will pass the load test, and it runs with that relay jumpered it should be the ecm.

Looking at the diagram if it runs with pin B and D jumpered, or D grounded, it almost has to be blue and yellow wire from pin C to 51, or the ecm.
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/25/21 04:41 PM


Appreciate the replies! beer

I think I'm just gonna go ahead and buy another ECM. It'll either fix it, or I'll have a backup for later. They're not getting any easier to find.

Now, do I do the junkyard crawl, buy one from rockauto/ebay, or have mine 'rebuilt'?

nervous
Posted By: 3hundred

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/25/21 04:43 PM

Originally Posted by Satilite73
Am I possibly looking at a bad ECM? confused


It's quite possible. They seem to do well for 20 ~ 25 years and go bad in some way, most commonly the voltage regulator function quits. Buying a used one is going down the same road you're already on, buying a rebuilt one is a crap shoot with worse odds. We got one out of Florida for little sisters old van. It's done well, until the van died of unrelated causes.
Posted By: 4406bbl

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 07/25/21 07:51 PM

Originally Posted by Satilite73

Appreciate the replies! beer

I think I'm just gonna go ahead and buy another ECM. It'll either fix it, or I'll have a backup for later. They're not getting any easier to find.

Now, do I do the junkyard crawl, buy one from rockauto/ebay, or have mine 'rebuilt'?

nervous


Only you can answer that question. I have had decent luck buying pcm both ways. I would at least confirm the blue, and blue/yellow wires can handle a load before I spent my money unless a spare is what you want. In the diesel world the engine computer is $900, so I like to make sure the wires can handle a load, as I have found that problem a lot, especially on the asd circuit.
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 08/01/21 10:11 PM


Slight delay on this. I tried to source an ECM from local PAP yards and kept finding '92 - older or '95 -newer. Six years ago when I bought this thing, Dakotas were pretty easy to find. Now......not so much. *sigh* hindsight being 20/20 and all that. spank

On to ebay............... nervous

(I haven't load tested yet. It's been to dang hot out). pity
Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 08/06/21 11:49 PM


I found a few used ECMs on ebay and ultimately bought one from a vendor called 'partwheeler' based out of Colorado. I chose them because of price, they didn't require a core, and look to have a pretty good return policy if need be.

I placed my order this past Wed and was told I would get it either Mon or Tues next week..........it arrived today (Fri). shock penguin

So, right after work, I went over and installed this 'new' ECM.................. nervous The truck fired right up. The truck is still on stands, so I just let it idle for about 10 minutes or so. Even without driving it, I noticed two differences almost immediately, the OD switch works properly again, and the tachometer works again. Hard to tell 100% without driving it but throttle response seemed quicker too when I winged it a few times.

I'll go over tomorrow and put the bed and wheels back on it so I can give it a proper test drive.

While looking for ECM's on ebay, I came across a vendor that rebuilds/refurbishes ECMs (all models) I may go that route with my original one to have it as backup. work

Big THANK YOU for all the help with this problem! It is VERY appreciated! beer
Posted By: 4406bbl

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 08/07/21 03:20 AM

Glad it runs. Be careful who you use to do a reman, some prorate the one year warranty, and only cover what they fix, not the whole unit. Dodge computers can only be opened and unfolded so many times, like 4, then they are junk
Anyway fighting with a certain rebuild in Florida, a cummins expert, that claims the pcm we sent is perfect, it will not hold the ASD relay down, that circuit cannot even carry a 100 milliamp load, I asked did you even test it. Assholes, made the kid change the crank and cam sensor, batteries, dodge dealer checked all wiring, they said all good pcm bad, I load tested everything, all good, what a joke these guys are. Have a used one coming. Maybe me asking them did you load test that switched ground, or just use a meter or scope, pissed them off, oh well.

Posted By: SattyNoCar

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 09/05/21 09:48 PM



I'll go over tomorrow and put the bed and wheels back on it so I can give it a proper test drive.

Well, THAT didn't happen.......until today. blush Between my foot issues and summer temps fully kicking in, it just kept getting put off. I'm kinda embarrassed this whole fiasco took 4 months...........

Anywho......

Went over this morning at the butt crack of dawn (8 AM whistling ) and got it all back together before the temps got unbearable again. She runs good! Put about 5 miles on it. I'm guessing the computer is relearning as the truck ran noticeable smoother when I was done.





I have a few other issues I want to tend to before making it my driver again, but its a HUGE load off my mind knowing that it does run and drive once again. cool

Another big THANK YOU for all the help! bow beer
Posted By: moparx

Re: Fuel Pump Diagnosis '93 Dakota.......next question - 09/06/21 02:56 PM

hope it keeps running good for you ! up
beer
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