Truck stalled first time ever 194K miles believe the current IP has about 30K on it. No fault codes. Started after 20 min. and got me home with no issues. I suspect the FSM. Should I check anything else before I run out and order one and what is the most updated P/N for it. Any help is great.

You could try pushing the pin receptacles closer together on the FSD connector.


Might want to check for lift pump opperation first, lack of pressure at the IP will stall it.

When it first stalled I reseated and all the connectors on the IP including the FSM, it did not resart. I just checked the lift pump but I'm not sure what its suppesed to do when, w/ key ON engine NOT running no fuel comes out, when engine is running alot of fuel comes out. The nature of the stall made me think the prob was electrical because it showed no signs, it was running fine then just stopped and wouldn't restart for about 20min.


Today it started perfectly and ran for 10min before I shut it off w/no issues.

with the key on, engine off, fuel should pump out of the filter when it is opened

I'll double check the fuel pump, but nothing came out unless the engine was running. Does any one have a part # for the lift pump so I can check out gmpartsdirect.com. If anyone is interested they have the FSM for $180+shipping, the dealer wants almost twice that.

Should I check power to the lift pump and/or suspect the OPS.

If you are not getting fuel with the Key On and the engine not running it is not the OPS or the fuel pump you should be looking at it is the fuel pump relay that controls voltage to the pump at that point. The relay is on the fuse panel under the hood and if it is working you will see voltage on the gray wire at the OPS and at the pump. If you do not have voltage on the gray wire swap the relay with one of the others there, they are all the same part #, as a test.

Matt - the '94-95 OBD-I trucks use START to energize the lift pump.


Pump will not run Key On, engine not running - only the OBD-II's do that.


Pull the fuse, by the LP Relay, short one terminal of the fuseholder to Battery, lift pump will run.


Will not damage anything if you apply Battery to either terminal - only the one tied to the pump will be effected.

If you put the truck in gear and hold the key to the start position, truck won't start, the lift pump is energized. This is a good way to bleed air after a filter change and to check if the lift pump is any good without getting under the hood or under the truck. If everything is quiet you can hear the pump running.


After this check start the truck and open the bleed "T" valve at the thermostat housing to check the OPS circuit. If no fuel comes out then the OPS is dead, most of the time.