So trying to chase down an intermittent problem, stalls hot or cold, but starts right up again and goes. Driving me crazy. So since I'm flying blind I figured why not make sure I have good engine ground. Found a perfect cable on '02 Intrepid 2.7, goes from the negative battery connection on the fenderwell on pass side, to the other side, grounding under a starter bolt. Stratus has a similar secondary ground attachment point on the driver side due to the odd battery location, so I hooked the serrated end there and the other end to an unused drilled and tapped bolt hole on the front of the engine block. I used the bolt hole closest to the driver side but there is actually one further toward pass side and lower that would be better to take up some of the slack in the cable, but I didn't want to get dirty. Used a bracket bolt from the yard, similar, M10 x 1.50. At least I have good ground.

If anybody can point me in the right direction on this annoying stall, please do so. I gotta get this thing squared away. Already tried a different crank sensor, swapped the ASD relay with one of the fan relays, did basic visual inspection. Also unplugged the IAC and the RPMs dropped. So it's doing something, just don't know if it's the right thing. --

MT

 

Well, interesting progress on this. Still having trouble having the fault manifest long enough to test things. Filled it up with gas, seemed worse rather than better. Swapped the fuel filter, old one had Ma Mopar emblem on it so likely was 17 years old. And those damned 'quick' disconnect fittings. Nothing quick about them. As I went to crank it to test for leaks in the cool of the evening I could not hear the fuel pump prime, and sure enough, the engine would crank but not start. Tried again, same thing...good...ran and got my timing light, and it appears that it was also not getting spark. I went to proble the ASD relay out pin at the coil 3-pin connector, and not sure it was making good contact, but showed no voltage with KOEO. Then I kept probing for better contact and CLICK - things started making noise. Of course the engine then started. Good - as I suspected it is a binary, on/off, electrical problem. Not a bad fuel pump either; that wouldn't affect the ignition.

So, ran back to my wiring diagram, and while the fuel injectors share common circuitry with the ignition through the ASD wiring, the fuel pump DOES NOT, at least as far as I can see. And I can't see that any ignition switch wiring feeds both; they seem to route thru different fuses/circuits. So I'm currently thinking either bad ground at the fuse block, or bad PCM. My diagram shows inputs and outputs at the PCM but I have no way to know what goes on inside, or how circuits connect in there. Ideas? Short to ground?

Oh, I am still going to run yet another redundant ground, this time to the head, since apparently aluminum conducts better than cast iron. There are two unused, drilled and tapped holes on the head, M8 x 1.25. I'll use one of those. I don't expect that to resolve the issue; just for giggles.

MT

 

Oh, fuses 5 & 8 both come from the same 'always on' 12V circuit. 5 feeds the ASD thus the ignition, and 8 feeds the fuel pump. I'll look there over the weekend,

MT

 

Closing the loop here. Turns out I was on the right track from the beginning and didn't know it. It would appear that it was a bad ground for the PCM, at the small wires that bolt to the driver side strut tower, labeled G102 on the wiring diagram. I was playing around with a toggle setup to run some diagnostics, and pulled that small short bolt which really just threads into the sheetmetal, and it was painted underneath. So, I sanded it clean and then roughed it up with a battery terminal cleaner. At first nothing changed, but then I had to pull it again, and re-tightenend it, and that apparently fixed it. It fits with the symptoms. I am going to beef it up with a redundant cable, probably just from that point to the negative battery access point right next to it. It's no wonder it stopped making contact; really cheesy setup there.

 

One last thing, scored a perfect ground strap off a '99 Intrepid, from the pass side of engine. P/N is 04760558AE. This thing has several terminations on it, including a very short strap with ring connectors, 1 small for the sheet metal bolt, and 1 big one for the negative battery access point bolt. If it reaches far enough, I might be able to ground another part of it at the cylinder head. I will need to slightly drill out that connector to clear the bolt. This thing WILL NOT have grounding issues after this. See pic.

MT

 

Hey Mealticket - thanks for all the info about this important issue that could stall stock cars. Guess an upgrade makes sense. Thanks for all of that research.

MT

 

No problem.

MT

 

I guess you're getting the idea that this isn't a very active corner of the Forum groups.. ;-) Thanks for posting what you have though as it may help somebody facing problems and using Google searches to locate info.

 

As you discovered, it's a good idea to check for continuity to ground on the circuits coming from the PCM and TCM since those are generally fed from a common ground point through those controllers to the sensors and some of the relays.

 

Thanks, Douggro. Well, yeah, this is important. This car is my stepmoms's daily and it appears that since it's the base econo model, some things are not engineered as they could be. Just looking at the Intrepid, even with the well-known engine snafus, you can just see that they engineered more into it. So that's why I've been pilfering stuff from them in the yards. Looking up that Intrepid ground snap, apparently it's just a noise suppression thing for the audio! And it's far better than the Stratus ground for the bloody PCM! So yeah, this upgrade needs to get out there for anybody driving something like this. As an aside, I believe Mopar re-entered Nascar with the Intrepid back then; of course it would be rear drive with a V8, but it's still interesting.

MT