Electrical issue killing engine

[Rochev]

I have a 2005 Silverado with an undiagnosed electrical issue. Back in June I started it and after a few seconds, the engine slowly revved up to about 2500rpm and died. It cranked over fine but wouldn't start. I tried a lot but assumed the fuel pump died.

Last month I tried starting it again just to see and it started up fine. I've been using it somewhat regularly. I generally baby the motor to save gas but I pulled onto a road and accidentally pulled out kind of close to someone. I took off fast and it shifted at about 4500rpm. Maybe 10 seconds later the engine started dying and hovered around 400rpm at 55 mph. It then died and I had to prevent it from rolling over in a ditch since everything else died.

Luckily after many attempts it started back up. I then remembered that the night before it first died in June I was driving it hard to "clear" everything out and get it going since it mostly just sits. Maybe a coincidence but it does seem that when it's driven hard, it'll end up stalling and may not start up again for months?

I'm not sure where to start looking.

 

[supton]

Maine? check ground connections. and other rust spots.

not driven a lot? low battery?

no evap codes? i mean old gas can be an issue.

 

[Chris142]

Try cleaning the mass air flow senser

 

[i6pwr]

Check for a securely mounted battery and/or loose battery connections. If a side terminal just because it's tight doesn't mean the "claws" are in good contact with the terminal.

How dirty is your throttle body?

Some good tips given above also.

 

[wtd]

Any codes in the ECM?

 

[3800Series]

Disconnect the throttle position sensor, try again. Vehicle should run in loop when disconnected. From past experience dramatic RPM issues mostly end up as TPS issues be it the sensor, or wiring too the sensor.

 

[Jethro_Bob]

Make sure the bolt connecting the wire harness the the ecm is tight, I've seen that a couple of times.

Also seen a heat shield on an s10 starter break off and would contact the battery cable to ground on aggressive turns. When it would short it would kill the engine.

 

[Lubener]

Check for codes. Start with the basics. I would connect a gauge to verify proper fuel pressure AT THE TIME the engine fails to start. If the problem occurs often, situate the gauge so that you can easily see it while you are driving and at the time the engine dies. If that checks ok, look for a loss of spark. "Most "sensors will not cause the engine to die and fail to restart.

 

[Randol]

Make sure the bolt connecting the wire harness the the ecm is tight, I've seen that a couple of times.

Also seen a heat shield on an s10 starter break off and would contact the battery cable to ground on aggressive turns. When it would short it would kill the engine.

I had a 96 GMC that would shut down intermittently. It turned out to be a large red wire running across the core support going directly to the ECU from the battery, Loose / corroded connection.

 

[mk378]

What @Lubener said. Since there are long periods of time that it won't start at all, take that opportunity to go through the complete "cranks but won't start" troubleshooting drill. Assume nothing.

 

[Rochev]

Good points I'll go through all these. It happened at a busy intersection after driving gently so it's definitely not when it's driven hard. If I let it sit a few minutes it'll almost start back up.

No codes stores or pending.

 

[mk378]

Part of the drill is to check that all the OBD live readings make sense while cranking though not starting, especially rpm and airflow.

 

[GON]

Not your model truck, be we had a 1998 S10 that would intermittently die. Also, the S10 would not start intermittently.

Ended up being a corroded fuel pump ground. The S10 fuel pump is located in the middle of the frame. The ground for the fuel pump was located at the very end of the driver's side of the bed, shared the same ground with the tail lights if I remember correctly. The wire gauge was tiny, and the corrosion was all it took to intermittently killed the truck while driving. Amazed GM used not only such a thin wire for the fuel pump ground but rant the wire about as far as possible from the actual fuel pump.

Two weeks of troubleshooting- 30 minute repair.

 

[LazyDog]

Before you replace any parts, check the ground side of the system: The ground straps below the cabin turn into spaghetti.

 

[Rochev]

I was thinking a ground issue as well since they are all corroded and I had to redo all of them. Also had to repair the ones under the bed in the rear since I had no blinker or brake lights.

Before it died again it was revving unusually high before shifting. It will now only start briefly on starting fluid. Haven't gotten it started again. Seems like the fuel pump but I ll be checking the grounds again first since it's the quickest.