maraakate

Hello, not sure if this is the appropriate subsection of the forum so if it's in the wrong spot I apologize.

I have a 1991 Lebaron GTC Convertible V6 3.0L (non-turbo) Automatic Trans that has been running OK for 3 years with a somewhat whiney fuel pump. The other week I was sitting in traffic and went to inch forward and the car wouldn't move forward so I thought maybe the trans was acting funny (it never has but I do know that they are known for trans issues) so I went to shift into park with the intention of shifting into drive and then the car stalled out. It wouldn't restart so I had it towed to my work. I work in the body shop at a Ford dealership so I am able to work on this in the evenings with an experienced tech.

Anyways, I replaced the fuel pump without checking anything else first because the car fired up as soon as I got it off the tow truck and I knew it was overdue for a pump anyways. Replaced the pump and the car still wouldn't start. Checked for power running to the pump and it does prime. Then we checked the fuel injectors and power was going to them. Checked with a noid light and no pulses are being generated for the injectors.

So we let it sit for a few days while I did some research. Checked the code and found it was giving a Code 42 about the ASD Relay. He checked the relay (now how thorough the test was I am unsure) and apparently it's OK.

We then removed the airbox checked for any potentially obvious bad wiring which the car had some previously since this car sat outside for literally 15 years and some critters did chew on various wires at some point. This includes unwinding all the tape, removing the housing for the wires, etc. all the way from the fuse box area to the the otherside by the map sensors. There was some insulation peeled back on one of the wires running to the injectors under the air box and we checked this and it was OK. He checked the wires and the positives are reading about 6.7-7.2ohms consistently.

There was also a 2-pin connector that wasn't plugged into anything by the fuel injector pigtail and was being melted by the exhaust. It looks like it may have went somewhere down by the transmission. Not sure if this is for some accessory wiring or what the issue is. The car has been in a collision before and there was some ground wires it appears that were redone down by the transmission. If someone needs pictures of this damage and needs to know the wiring colour for that connector I can provide it.

The large positive wire coming from the battery to the fuel box was partially cut open, exposing some of the wire and a bit of corrosion and was rubbing on the master cylinder. RTV'd the exposed area, wrapped it in electrical tape and checked all the fuses and they are checking out OK.

The car will run on starting fluid so I think we can rule out the coil, distributor, and timing belt.

One of the wires running to the MAP sensor is a bit suspect, haven't replaced this yet; but the tech was saying the car should at least be able to run, maybe not very well, but still run nonetheless despite the somewhat chewed wire running to the sensor.

I disconnected the fuel lines running to the fuel filter and some fuel does come out at the initial prime and I bypassed the fuel filter to be certain that it wasn't plugged. If I check the fuel lines by the rails nothing is coming out but I'm not sure if this is because the ASD relay is preventing the pump from doing its job.

The dealership I work at has a Chrysler location on the other end of town and I'm going to see on Monday if they have a DRB-II tool with the appropriate adapter that would allow me to at least run the test to energize the fuel pump; but considering the injectors aren't pulsating I don't think it's a case of a plugged line.

I very likely suspect the computer at this point; but I'm not sure. I do have the official dealer manuals for the car but some of the information is a bit vague on exact diagnostics to follow to fix this issue.

Starting to run out of ideas at this point, short of replacing the computer (which I do have one coming, but I do very much dislike shotgunning parts and would like to learn from this situation) and checking the appropriate wires the 60 pin connector actually cares about to trigger code 42. I'm not sure which specific wires I should be caring about.

Any help/advice is appreciated.

EDIT:

The car is an AJ Body for anyone who is referencing the dealer manuals.

RacerHog

Hummmm. Whats interesting to me... Is, "Correct me if I'm Wrong". But in order for the injectors to work, you have to have a tach signal, as a rule of thumb?
So, If its got spark and no signal to the injectors???? Very well could be the PCM or the ASD Relay.

Do the injector have power? That would point to the ASD.... Or did they loose the ground back to the PCM? That would be a PCM issue..

Just my 2 cents

I think your on the rite coarse, if you can get ahold of a DBR scan tool.

maraakate

I am taking the tech who assisted me on his word of performing the injector test properly; but I was discussing this issue on another forum and someone said that I should check with a test light on the common wire for the injectors (which in this case is a dark green wire). Verify that it comes on for a second during the ignition cycle and continues to illuminate during cranking. Hopefully I can get a chance to do this tomorrow.

My personal theory is that positive terminal that was coming from the battery to the fuse box was intermittently making contact on the master cylinder slowly killing the computer or cracked/cold solder joint from age in the computer itself. Either way, will check the injectors again and the fuel pump circuitry again on Monday and let you know my results. The other forum also posted some information about testing the ASD relay itself on this particular model the test says to disconnect the computer and check with an ohm meter the DG/BK wire between the relay and computer for resistance. If it's reading under 10 ohm to inspect the computer or if it's very high then repair the wire. So depending on how hard it is to find this wire I will try and do that test at the same time.

Not sure if I will be able to get access to the DRB2 tool; hoping the Chrysler branch of the dealership had the foresight to save the tools.

RacerHog

Not questioning anybodies technical skills...
Just hoping get you narrowed down to getting things fixed...
Anyway... A Modis, Solus, Midtronics, PicoScope, or something along those lines will help you get it done...

maraakate

Never used these tools before. I do a lot of vintage stereo amplifier and arcade repair so I do have analog oscilloscopes. Maybe they could be useful, but without knowing the waves that I should be seeing it's a bit hard to say and I'm hoping it's just something simple that I'm overlooking.

Will find out tomorrow if I can get a hold of the DRB2 tool with the appropriate adapter and cartridge. I'm certain if I can borrow one that would really help narrow things down.

maraakate

Found a tech who had the appropriate DRB2 tool!


The problem (so far) is the replacement fuel pump.

I cleared the codes with the DRB2 tool; tried to do a few cranks, no codes except 12/battery disconnect (good).
Ran the ASD relay test on the tool; it clicks, reads ON during initial prime, switches to OFF, then switches back to ON when cranking (good).
Pulse was reading ~60 then about ~55 during a crank.
Ran injector test on all injectors all are clicking (good).
TPS voltage is below 1.00 volts at closed throttle (good).
Ran fuel system test, I can hear the pump whirring (good).
I also viewed the sensor outputs and saw stuff occuring for MAP, TPS, and Barometric. All seem to be working.

At this point I was out of ideas; tech told me to run the fuel pressure test and he assisted me. Ran the fuel system test again on the scan tool and it took a while for the gas to start coming out of the release valve on the pressure tester and it was trickling. Pressure is basically 0. There is no fuel filter since I bypassed this to be sure it wasn't plugged. So unfortunately it looks like a faulty pump; which is a real shame as I went out of my way to get a Bosch pump from amazon.

In the mean time, I'm gonna have the parts guy at the dealership get me an aftermarket pump and filter and hook it up again and run the fuel system test make sure its good; fix up the few questionable wires before they become a bigger issue and hopefully the problem is resolved.

RacerHog

Fingers crossed..

maraakate

Indeed. Hopefully NAPA can produce a pump for me by the end of the business today tomorrow, and that it holds proper pressure.

Will be sure to update on the progress.

maraakate

Still no good. Got another pump (this time an Airtex). The tank has about 4-5 gallons in it and I added an extra gallon to be certain. I disconnected both lines at the fuel pump and nothing comes out. I tried putting my finger one the return line and feel very little suction.

Someone on another forum said it's getting harder to find a good pump for this car; but I will also check the pigtail and make sure it's actually getting 12 volts. Maybe there is a corrosion issue somewhere that is preventing it from getting the full 12 volts but the replacement pump is rather loud so I doubt that is the case.

Could the pumps be wired backwards? If they were would gas at least come out of one of those ends?

maraakate

Okay. Dropped the tank, saw nothing funny floating around in there, did a pressure test it was about 15 psi. Got one more pump (this time a Spectra Premium) and it fired right up. Drove it home and all is well. Thanks for the help from everyone.

RacerHog

How many faulty pumps did you get before you got a good one.... Hope that really did fix it.... Keep up posted....
Hope all is good...

maraakate

First one was a Bosch one from amazon, still need to send that one back... Held no pressure.

Second one was an Airtex from Federated. That one would hold about 15psi.

Third one is a Spectra Premium. Was from an independent parts supplier not sure who they are associated with.

So, overall, 3 replacement pumps until I found a good one! Will keep you posted when I drive it around a bit more. Plan to take it around for a little trip tomorrow.