Stalls over bumps still with new PMD

[3116biff]

Hello all. I have searched and read the stalling issues, but I have not been able to figure this out. I have replaced the PMD with a remote mounted one. It has a new lift pump. When I go over bumps at low speeds the truck dies, but will start up. If I go over bumps under throttle it doesn't stall, but sometimes hicups.Once after stalling it would not start up for about 20 mins. Now somtimes the engine light comes on. Also I just noticed if the truck is running with the hood open and then I shut the hood it almost stalls. Any one else have this problem and find a cure. Oh ya my truck is a 1995 2500 with 350,000 kms. Thx for any help. Scott

[Warren96]

I have been chasing electricals all my life. How about checking the codes stored in the computer first?

[JoeX87000031]

I once had a car that would charge the battery when it idled in park, but if you drove it around for 30mins +, it wouldn't start after stopping and shutting it down. Turns out it was a stripped/loose battery terminal. Wiggled a bunch on the road and the alternater couldn't charge the battery. Maybe that braided gound is bad and the one from the battery up to the alternater bracket is intermittent. Something gotta be taking the ground/power from that PMD. I don't know that much, and you probally checked it all already, but I would check that braided ground and ohm the battery cables, maybe do the bolt/nut terminal mod, works great on my truck. Take care.

[Robyn]

I agree.

Check the codes that are stored.

Bw sure all the battery connections are good including the power lead from the battery to the main junction box.
Be sure the grounds on the RH rear of the intake manifold are all good.

Check the ground wire to the IP and be sure its there and tight.

This sounds like a loose or poor connection somewhere.

The area where the main cables pass through the firewall and head to the computer should be checked too.

Pull the glove box out and check the connections on the computer too.


The main harness that feed the engine (Passes under the intake and feeds all the sensors as well as the IP) can have issues.

Good luck

Robyn

[3116biff]

Thx for the input. Last nite I narrowed it down to the steering column. Everytime i tilt the steering column down with a bit of force the truck would almost stall. So I pulled the bottom plastic of the steering column off and wiggled the wires and hit the ignition switch, nothing happened. I then tilted the steering column down with force again and it did not sputter. Maybe the plastic piece was putting enough force on a bad wire so when it jolted it would cause it to stall out. Not sure. I have not had a chance to road test yet.So for now the plastic piece is off.

[3116biff]

Well my father inlaw drove it to Vancouver, about a 4hr dr. It stalled on him a few times and hiccupped aswell. He checked and cleaned the ground connections and battery connections. Still the same. I think I am going to give up and sell it. I would like to feel confident about driving this truck anywhere, but I just don't.

[Patrick m.]

95 models seem to have many problems with the ignition switch. i have a 95, and have replace many ignition switches in the 95 model trucks.
It s pretty easy to do, odds are it will solve your problem.

[3116biff]

Patrick did you just replace the ignition switch through trial and error or did a code show up?? It is not a cheap item to just replace without knowing for sure. Is there a check for it?? Thx Scott

[Patrick m.]

no codes, after chasing an intermittant condition on my truck, i caught a voltage drop on a complete row of fuses. (these fuses are fed by the ignition switch). the switch has several power feeds going to different systems, one of these contacts within the switch was failing.
This failing contact manifests itself in different ways on different trucks, depending on which power feed contact fails first.
If you need to verify that this is what is happening to your truck, get a multi meter, preferably a "Fluke" that will measure and record with a "min-max" feature, as sometimes the voltage drop is very quick and you may not see it happen.
You can take the measurement at the ignition switch main connector, or at the fuse panel, which ever is easier for you.
Any voltage drop over 1 volt with engine running is suspect, mine was dropping to 7 volts just long enough for the ecm to put the trans in limp mode. but again, symptoms will vary depending on which power feed circuit is dropping.

Once some of the others read this, im sure more will chime in about the ignition switch in the 95 model trucks.

[3116biff]

K, Thx. I will try that. I appreciate the help. Scott

[3116biff]

Ok so what is a good price for an ignition switch? I was told by a place I usually buy my auto parts from 230.00. I did find one online for 100.00. Is this ignition switch only for the 95 96 yrs. Is it worth it to go to pick a part and get one. Were these switchs bad in the gassers to??

[Patrick m.]

i would only get a new as all of those trucks even gas trucks has problems with this switch Im not sure what the difference is, but it seems to be only 95 models. The screws that retain it are "E" sockets, or inverted torx, i think it is a "E4" socket, but not 100% on the size. The parts house will have it if you dont already. The switch also has a length of harness as part of the assembly, and the harness connector bolts together under the dash.
Not a tough job.

[ol9465er]

I have not had the same issue but did have issues with weird codes a few years ago and it was just because of electrical connections being loose.

Just as a matter of course I would check all your grounds on the engine and make sure they are tight (if they have a nut under and nut over check the bottom nuts too as the top nut may be tight but the bottom not be). I would also disconnect and re-connect all the connectors at the computer. Connector connections dry out over time and a disconnect/re-connect reseats them. I would check the other connections in the circuit also.

[3116biff]

Well after leaving the truck with my father inlaw for a few mths. He found and fixed the problem. I was in no rush for the truck, luckily. He pulled the dash off and checked all the wire connections. He found one near the computer that was loose. He fixed that connection and all is good. I was thinking of selling it, but we will see. It runs so nice. I havnt even driven it enough to check what I am getting for fuel mileage. With the crooks at the oil companies charging more for diesel than gas now I hope my mileage is good.

But there is some blow by at the dipstick. My father inlaw thinks it is carboned up. He has a few tricks to help. It also ran hot for him on his drive to Vancouver going up a long steep climb. After searching on here about over heating I took the grill off and the coolers are pretty plugged with little rocks. As soon as it warms up here a little I will start the task off cleaning out these coolers.

The truck use to be a pilot truck in Alberta and then was sold to guy who use to putt around in it.

This site is awesome with all the knowledge on here. I will post some pics of it soon.