My current project is a 1956 Canadian Dodge (Plymouth) 2 door wagon that I am trying to get finished so that I can start on my next and last project. I have installed a 318 (5.2) (my first fuel injected engine project) out of a 1992 Dakota in the ’56 with the original fuel pump in a jeep fuel tank (same fuel pump locking ring). The donor was a running and driving truck before I screwed it up. I have had the '56 running (but not moving) many times but I could not get the Dakota fuel gauge installed in the dash to work. I bought a new Carter fuel pump and the arm for the fuel gauge variable resistor fell off, junk. After two months of frustration I put a aftermarket fuel gauge under the dash and sender in the tank. The WEIRDEST thing was I could get the GAUGE to work with the pump on the bench but not in the tank. I have put the original fuel pump back into the tank.

The car has now sat for another couple of months (Son’s backhoe hydraulic hose job) and now the '56 will not start, and I can not hear the pump, but if the engine does not start the engine controller via the crankshaft position sensor only lets the pump run for 3 seconds for the prime. The WEIRDEST thing was I could get the PUMP to work with the pump on the bench but not in the tank. Same as the gauge. So I hot wired the fuel pump relay and got the pump to run and it did start but ran poorly and would not stay running.

I have triple checked the wiring to the pump including the grounds. I will do tests on the ECM next I guess. Any ideas anyone? Thanks.

Got to start someplace, so: The fuel pump has its own power and its own ground, and the gauge has its own power and its own ground. Then there is a low fuel light that attaches to the gauge.
With all your wiring changes, I would want to be sure that you have not mixed the two grounds up, and that you don't have something connected to the low fuel light wire (which i believe is a simple ground for the dash light as well)

The gauge and the pump are separate things that simply use the fuel pump housing to hold the sending unit for the gauge, on the original fuel pump set up. one should work, even if the other doesn't. Since neither is working while in the tank, I suspect a wire problem at the pump wire connecting point.

That is where I would start. I would also suggest you remove however you hot wired the pump to stay running and put it back like it originally was.

Just another thought... about a month ago I ran into this problem:
My experience is, these pumps don't like to be left sit very well. Removing and reinstalling them with times of sitting in between can't be good. The fuel pump in my coupe died (90 Dakota stuff) after a year of just starting it and moving the car just to mow around it. When I was ready to start driving it again, it would run for a few minutes, then die. If you left it sit anywhere between 15 minutes and a couple hours, it would work great for another few minutes before it just quit working again. Finally, after a few days of messing with it, it just quit all together until I rounded all the stuff up to replaced it. The day I was ready to start to install the new pump, the car fired right back up and I drove it into the garage. replacing the old pump with a brand new one solved the problem. I have ran 3 tanks full of fuel through it since the pump replacement.

Thanks Gene, much appreciated. (old man work in progress)

As soon as you put the ignition to "on" the pcm will prime the pump. This is enough to get the engine to start(49 psi). After the pcm sees the engine is running it will turn on the fuel pump via the relay. Not sure if there is a ground wire in the harness going to the tank but i would make sure the sender has a good ground to the body/negative battery terminal. I would check to see if you are getting full fuel pressure at key on. Also make sure the battery has a good charge. The magnum pcm's don't like weak battery's.

Not exactly related but something to check while apart. Are the Jeep and Dakota tanks the same depth?

I've seen situations where the wrong pump was installed and wouldn't reach the bottom of the tank. For example a pump for a standard tank installed in a larger capacity tank. I think this was a common mix up on Wranglers.

It is VERY related, great question. This is the original Dakota pump (older Carter ?) with the metal frame that is somewhat adjustable, maybe used in different models, the Dakota has a 15 or 22 gallon tank but they both use the same pump. This has been a long term problem / situation with a short term old guy memory so to the best of my recollection I adjusted that pump as short as possible because the strainer was hitting on the tank bottom. I checked the depth with a tape measure and they were the same. I think I changed the actual pump motor with a new replacement one because you can in that model. When the fuel gauge would not work and out of desperation (frustration) I replaced the pump assembly with a new style plastic Carter (junk) also with semi-adjustable plastic height feature until the float arm fell off. I can not hear at all the pump running now when the relay is bypassed when there is power to the pump terminal. I have given up and took out a second mortgage to order a new Bosch pump, even the Delphi had poor reviews. To be continued,

Thank you for your help, I do appreciate it. If the following sounds cranky it because I am very old and have to get thoughts down on paper before I forget them.


Yes, but only for 3 seconds, hard to tell if the pump is running.

But what if it is not running ?
Yes there are two grounds, one for the gauge and one for the pump but I think they become a common splice.


No pressure if the pump is not running.


The battery has a battery tender that is on all the time.

Jeep fuel tank in 1956 Dodge wagon, with Dakota pump.

I bought a replacement fuel pump for my 90 Dakota at Orilly's for around $75 (just the pump) about a month ago (the pump comes with out the strainer, pay the extra $15 and get a new one of those too, because the old strainer won't come off the old pump in one piece, like they told me they would). Can't say how long its going to last, but its working well for right now.

Depending on which EFI system you have, most have a port (with a cap on it) on the fuel rail on the motor with a Schneider (?) valve (looks like a stem for adding air to tires). If you remove the cap, and depress the valve, gas should squirt out if the pump works at all. Turn the key on for 5 seconds, then turn it off, pop the cap off and depress the valve to see if it squirts gas or not (be prepared, if it has gas, it comes out fast, its under pressure). If no gas squirts out, the pump didn't run. Its that simple. The pump pressurizes the fuel line so fuel is available when the injectors open to start the motor.

I was thinking of that ........ can I use a tire gauge and a rag and a fire extinguisher ?

The pump has a check valve so once the pump primes the system(for 3 seconds) it will hold the pressure. That is if the check valve is working! Pump does not need to stay running during crank only after the engine starts.

I would probably use a small flat blade screwdriver, the gas probably wouldn't be very good for the tire gauge...
If nothing is hot, the fire extinguisher probably won't be needed, but something to wipe up the sprayed gas might not be a bad idea. if there is no gas there, you know the pump isn't working. Pretty easy test, though could be a bit messy.

Good Lord, buy the test kit. It isn't the end of the world!!!

EFI Pressure Test Kit

Your wish is my command your Lord.
(too many choices for a old guy before your recommendation, thanks)

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Just another tool to sit on the work bench to probably never get used again. At almost 68, I'm not collecting tools anymore.

Well, I am 80 and I still am buying tools and that shows how really stupid I am. I hope my grandson will use them but I doubt it.

BUT, ... there is a selfish self interest greed reason (no surprise there) in this particular tool purchase, ... my next (and last) project is a "other make" also with fuel injection that is disassembled and has been sitting in storage for years, I am just anticipating what the automotive spirits will send my way because of my lack of planning and knowledge (as usual) . I can't wait to start on it !

If you never have to work on EFI vehicles, I agree, it's just a shop ornament. But if you do....another story. If you have a "no-start" condition with EFI, first thing I do is check the fuel rail pressure. I just had a friend with an intermittent no-start condition on a '96 S-10 with the 4.3. We were chasing our tails until we hooked up the test gauge and did multiple starts. It was obvious that the control relay was the problem. Replaced relay, all is good.

BTW, I'm 72 and I'm still buying tools I don't have.

See if any of the parts stores will rent you one.

"BTW, I'm 72 and I'm still buying tools I don't have. "


how well i know the feeling ! i'm a tick older, and i do the same, even if it's just for a one time use, and i'm also fabricating tools for stupid or odd circumstances.
these fabbed tools are usually "constructed" from a bucket of "junk" tools i keep around for just this purpose.
the bridgeport and the lathe get workouts during tool fabrication as well.
and then there is the problem of "tool storage"............... it just gets worse when you run out of storage or tool boxes to keep this "stuff in ! it never ends !
as i told member Crowbait, now that you are the executor of my estate, just look at all the "stuff" you will inherit or have to get rid of.........

Everything I own is EFI, has been since 2011. I have had a pretty good run with EFI stuff and I have built several rides with EFI. I'm not afraid of it, and I understand how it works. I have not had a need for a fuel pressure gauge set up so far, in all these years. I don't have the space to store things I don't use, and I don't have the money to waste on tools I probably won't use a second time. I am not addicted to this stuff, and I'm not collecting it.

I have younger friends that are in the automotive business, if I have a need for something I don't have, or can't figure out, I will go to them. I don't mind paying my younger friends for their equipment or their knowledge. Its the circle of life.When I was young, older people paid me to do the things they didn't know how to. Now that I'm older, its time for me to pay the younger guys to do the things I don't know how to.

When I retired in 2018, I quit working on other peoples cars. I sure don't intend to start doing that again. Its just my 3 piles of junk I need to keep running. Two have mid 1990s EFI systems that I have very good knowledge of, and the other has an 04 EFI system. I don't really care to work on anything concerning the 04. If it quits running, its going into a shop anyway, I'm not fixing much of anything on it.