91 s10 2.8 engine stalls

[stewpadassel]

Engine started stalling every once in a while at low rpm, no big deal the engine would fire right back up. Until one day it stalled and took almost 15 min to get back running. Seemed the more throttle you gave the more it would try to start. After a while it started back up and fortunately got it back home. If you kept the engine running at a high rpm it would stay running. Then the truck got to the point where it did not want to start at all. You can crank the engine and every once in a while the injectors will spit just enough fuel to let the engine fire a little bit. But never a constant spray. Once you eventually crank long enough the engine will start and run for a unknown amount of time. Shut the engine off as its running and will fire right back up. But if it die it will take forever to get started. No codes. Changed: tps, map sensor, iac, coil, cap, and rotor, also tested ignition module. Any ideas?

[MT-2500]

Originally Posted by stewpadassel

Engine started stalling every once in a while at low rpm, no big deal the engine would fire right back up. Until one day it stalled and took almost 15 min to get back running. Seemed the more throttle you gave the more it would try to start. After a while it started back up and fortunately got it back home. If you kept the engine running at a high rpm it would stay running. Then the truck got to the point where it did not want to start at all. You can crank the engine and every once in a while the injectors will spit just enough fuel to let the engine fire a little bit. But never a constant spray. Once you eventually crank long enough the engine will start and run for a unknown amount of time. Shut the engine off as its running and will fire right back up. But if it die it will take forever to get started. No codes. Changed: tps, map sensor, iac, coil, cap, and rotor, also tested ignition module. Any ideas?

When it quits or will not start.
You need to test for lose of spark or fuel pressure or injector pulse.

Post back what it is losing.

[stewpadassel]

Injector pulse

[MT-2500]

Originally Posted by stewpadassel

Injector pulse

Have you checked for lose of injector pulse from pcm?

Is the ign firing good when it loses injector pulse?
Good 12 volts to injectors and wiring good?

Does a pcm tap or twist test change anything?

[blazes9395]

If you have checked fuel and fual pressure checks out, and you can clearly see its not getting a good pulse from the injectors, your ignition module could be the problem(under the cap, on the distributor). Those years had a knack of overheating and shutting off until they cooled down and the process would start all over again. Goin to get them tested usually turned up alright because it worked when it was cool.