Randomly dies

[93shortbox]

I got a 93 2.3 manual that randomly dies while running and sometimes before it dies it feels like it falls on its face but if I keep my foot in it will stay running but will have no power and as soon as I let off it will completely die. If I wait about 30 secs it will fire back up and more often than not it will backfire when it turns over after it has died. Sometimes it will backfire before it dies. I have checked fuel pressure, replaced the plugs, wires, ICM, CPS, tested the ignition coils, cleaned the throttle body, cleaned the IAC. Would the timing being off cause this? Injector going bad? Another bad ICM? There is no check engine light and no warning before it dies. I am at a loss of where to go from here.

 

[sfwjesse]

Have you checked for vacuum leaks? listen for a sucking sound or use the smoke test to see if its being sucked in somewhere.

 

[93shortbox]

I sprayed the vacuum lines, intake, and around the throttle body with carb cleaner while it was running and got nothing. Anything else I should check?

 

[JCyr8511]

The truck randomly dies while running....down the road? or idling? Could be MAF sensor.Incorrect timing wouldn't start or would cause a constant rough running engine.

 

[auto02]

I got a 93 2.3 manual that randomly dies while running and sometimes before it dies it feels like it falls on its face but if I keep my foot in it will stay running but will have no power and as soon as I let off it will completely die. If I wait about 30 secs it will fire back up and more often than not it will backfire when it turns over after it has died. Sometimes it will backfire before it dies. I have checked fuel pressure, replaced the plugs, wires, ICM, CPS, tested the ignition coils, cleaned the throttle body, cleaned the IAC. Would the timing being off cause this? Injector going bad? Another bad ICM? There is no check engine light and no warning before it dies. I am at a loss of where to go from here.

I'm having the exact same problem with my 94!I changed the fuel pump,relay,ignition switch,computer,fpr,and checked inertia switch and still does it.I just put a new head on it and swapped on a new ICM which is what i'm currently thinking the problem is.It ran just fine before the head swap and ICM change(it skipped but was atleast driveable,had a cracked valve seat).

 

[93shortbox]

The truck randomly dies while running....down the road? or idling? Could be MAF sensor.Incorrect timing wouldn't start or would cause a constant rough running engine.

Dies while running and idling. I suspect it might be another bad ICM it is only a year old . It is acting the same as it was last year but now it is backfiring. I will try cleaning the MAF and see if that helps.

 

[Earl43P]

When it dies, shut off the key and pull over.

See if a strong spray of fuel comes out of the injector rail schraeder valve.

Since it is intermittent, find out whether it is spark or fuel.

Strong spray when it dies, rules out fuel pressure (which I think you'll find no pressure). Compare it to spray intensity present when shut off after running fine.

Use a rag, watch your eyes, all that. Depress it like a tire valve stem. Or use a gage.

So, it starts back up, but how?
If you crank forever to get it lit, try turning the key to run/off/run/off letting the fuel pump build up pressure, then crank the starter. Again, points to loss of fuel pressure.

 

[Bryan22]

I'm with earl on figuring out what it's lacking when it dies. But i'm leaning more towards an ignition system problem. Either way figure out whether it's fuel or spark and go from there. Also wouldn't hurt to check all grounds and battery terminals/cables. good luck!

 

[93shortbox]

I've had a fuel pressure gauge on it while it died (kind of a fluke) it had consistent strong fuel pressure. I'm leaning towards something ignition or sensor related but not having an engine light makes me think ignition.

 

[Bryan22]

Well if you've got pressure at the rail when it dies, i'd start checking the coil packs and have the ICM tested. And double check all the grounds and those 3 little bolts in the ICM.

 

[bilzy7]

I feel for ya... same thing happens when i get hard... next thing you know... putt putt...

 

[93shortbox]

Found it! Another bad ICM.

 

[Bryan22]

Good you found it, hope it was under warranty.