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engine stalls when warm, starts later
04-08-2012, 12:44 AM (This post was last modified: 04-16-2012 12:50 PM by maddctr666.)
Post: #1
engine stalls when warm, starts later
I've got a 1993, dodge ram 350 Van, 6.9 liter...
ran fine, all of a sudden once it warms up/bout 10 mins of driving. And it stalls. Just quits, at stop, or rolling. will restart after bout an hour and a half or so..
Good fuel pressure, relays, new plugs, wires, rotor, cap...
No visible, or measurable vacuum leaks...


Any help appreciated...Big GrinBig GrinBig Grin
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04-08-2012, 10:24 AM
Post: #2
RE: engine stalls when warm, starts later
Seeing as it starts again in an hour or so that tells us it's probably not a mechanical issue so the only other things left would be fuel or spark that goes away. (maybe: see below)

What I would do is get it going and bring along a can of starting fluid, when it quits give it a shot of starting fluid. If that helps for a second or two then you know you need to hunt down a fuel issue. If not, then you need to hunt down a spark isssue.

Seeing as the truck is near 20 years old (high mileage too?) you could be looking at a variety of typical age related probems. IOW, anything from a failing fuel pump to a bum ground, to a temp sensor that is just starting to go out of range but has not failed enough to set a code. Remember that this vintage will be OBD-I so the engine computer is not as fussy as the newer vehicles and will not set a code unless a sensor goes open or shorted as a general rule. OTOH, a full function scan that will read the actual sensor outputs could help once you narrow the cause down to spark or fuel.

I have seen more than once where a temp sender was showing a cold engine so fed TOO MUCH fuel and choked it out. In that case you will find spark but adding fuel (starting fluid) will still not allow it to start because it's too rich. Pulling a few plugs and seeing if they are black might give you a clue here.

Let us know how you make out.
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04-08-2012, 02:00 PM
Post: #3
RE: engine stalls when warm, starts later
(04-08-2012 10:24 AM)Rupe Wrote:  Seeing as it starts again in an hour or so that tells us it's probably not a mechanical issue so the only other things left would be fuel or spark that goes away. (maybe: see below)

What I would do is get it going and bring along a can of starting fluid, when it quits give it a shot of starting fluid. If that helps for a second or two then you know you need to hunt down a fuel issue. If not, then you need to hunt down a spark isssue.

Seeing as the truck is near 20 years old (high mileage too?) you could be looking at a variety of typical age related probems. IOW, anything from a failing fuel pump to a bum ground, to a temp sensor that is just starting to go out of range but has not failed enough to set a code. Remember that this vintage will be OBD-I so the engine computer is not as fussy as the newer vehicles and will not set a code unless a sensor goes open or shorted as a general rule. OTOH, a full function scan that will read the actual sensor outputs could help once you narrow the cause down to spark or fuel.

I have seen more than once where a temp sender was showing a cold engine so fed TOO MUCH fuel and choked it out. In that case you will find spark but adding fuel (starting fluid) will still not allow it to start because it's too rich. Pulling a few plugs and seeing if they are black might give you a clue here.

Let us know how you make out.
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04-16-2012, 12:33 PM (This post was last modified: 04-16-2012 12:49 PM by maddctr666.)
Post: #4
RE: engine stalls when warm, starts later
Thanks for the advise....

tried the starter fluid after it stalled, and it did crank over...
like i said, checked all the relays.
Could it still be a sensor of some sort?

Only trouble code is #55 - A/D Converter error... What, and where is this??? Can't find any refrence in my Chilton manual

but since it is fuel related should i pull the tank, and test fuel pump, and its components???
Just hate to drop the tank for nothing....
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04-16-2012, 10:11 PM
Post: #5
RE: engine stalls when warm, starts later
Hard to say but we have to sort something out here because "cranking" is just what happens when you turn the key. IOW, the starter cranks the engine. The key to my question is "does it catch / run for a moment" with the starting fluid? That is what we need to know. If it does then you certainly have a fuel issue so the next step is to find out exactly what the fuel pressure is and if there is an injector pulse. IOW, you are missing one of those.... no pulse or not enough fuel pressure.

BTW, a code 55 (if that's correct) is not a trouble code but it means you have reached the end of the code sequence. On most 95 and earlier vehicles without any problems the codes start at 12, which means the key is on but there's no ignition signal. (the engine is either not cranking or running) After it goes through all of the codes that are in storage it will give you a 55 and that means you are done reading the codes. The A/D error is likely just your scan tool telling you there's nothing else. (in geek terms the A/D stands for Analog / Digital, which is the information stream)

Soooo, back to basics..... you need spark, fuel at the correct pressure, and fuel delivery (injector pulse) at the cylinders.

What I would do double check the spark when it quits because on most of the earlier engines the spark signal is what drives the injector pulse. If you have spark then head for fuel pressure issues. You must use a proper gauge with the correct fittings to avoid causing a fire with leaking fuel while doing this part. We need to know what the fuel pressure is when it starts and what it is when it will NOT start.

Sorry I can't be more specific. I just don't have much experience with this particular vehicle, but the theory is all the same regardless of make.
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