-96 K1500 6.5 STALLS

[MATTIAS BJADE]

Hello! my 6,5 sometimes stalls in idle and then a orange light turnes on left of the guages(looks like an enging)and sometimes it jurkes ones and light comes on but it don

[rameye]

Mattias..

the power for the lift pump is fed from the oil pressure switch on the rear of the engine.

if you aren't getting fuel to the bleeder then the lift pump most likeley not working. i'm sure you figured that out already. work backwards from the lift pump checking for power up to the oil pressure switch. you can run a set of jumpers from your battery (use a fuse) to the lift pump to see if your pump is working. if the pump is OK than replace your oil pressure switch.

good luck

[rjwest]

If you have a 96 truck ( or older ).

The lift pump is operated by the PCM, through a relay.

Also, look under hood, driver side, very close to hood hinge. In the wire bundle ( look real good, it's hidden )
There should be a conector, it is open ( nothing
connected to it ). This is a jumper point for the
lift pump power:
IE: jumper 12v to this connector ( fused wire to be safe ) Lift pump will run continuesly for test/bleeding.

Normal Pump Operation: When ign turned on,
lift pump will run for a few seconds than shut off.
You will be able to here it run if you listen by fuel tank.

When engine starts ( sensed by PCM, Not oil pressure ) lift pump will be commanded on by PCM.

The oil pressure sw is only a fail safe circuit
in case Lift pump relay fails.

Cranking engine will raise oil pressure enough to turn on lift pump.

If your lift pump works with Jumper and not in normal operation, most likely the relay,

If lift pump does not work with jumper than probably lift pump or connectios.

Lastly: I think ( not sure )There is a code set when lift pump commanded on by PCM and PCM does not sense voltage at lift pump.....

[MATTIAS BJADE]

Ok! thanks,
exactly where is the oilpressure switch mounted?
but i think something else is wrong also, since it stalls with full tank and i got fuel of the bleeder rigt away and it starts directly. In previous stalls i had to bleed by injectors, but not now. Liftpump is always ticking when I have listned. tried to bleed drain by turning on off ignition but i never got any fuel until i cranked it when i towed it home half mile. I have 45k miles on truck, k1500

[MTTwister]

MATTIAS - The OPS is in thh engine valley - Drivers side - rear - buried ( ok hidden) under the intake manifold. I believe on the '95, you can put the truck in gear ( auto) and turn the key to start and the lift pump will also run without starting the engine. Rameye's and RJ's way is a lot easier than being in the cab, away from what's going on under the hood...

Also, Search on the OPS Relay setup - to take a big load off the OPS contacts - either with the current one, or with a replacement.

Good Luck

[rjwest]

You need to work on 1 problem at a time.


find the Connector to jumper the lift pump on and than check water drain for fuel, run at leat a QT
of fuel and watch for air bubles, if no bubbles
and good fuel pressure, Than most lickly the FSD
is causing stalls.

I assume your truck is a 96 or newer as stated in post title... on 96 The OP Sw will not cause
fuel starvation . Only affects 95 aand older....


Also Try to get codes read, In US some of the auto
parts stores will do this as a free service.....

[Turbine Doc]

Bad lift pump or loss of power to it does not cause engine to shutdown at idle, but will cause stumbling at load, a good IP will pull it's own fuel for basic running, but needs the lift pump for assist when engine is loaded up.

Go to the members area for trouble shooting tips, this sounds like a classic PMD, before going too deep, make sure basics are covered. GMs are prone to bad grounding loops for power to it's electronic devices, make sure all wiring connections are good, fuel filter is clean, no crud in the bowl, check power to the lift pump.

If you don't do the basics GM will check them for you at their high rates, and probably won't consider the extended policy if they find rust or a non functional Lift pump, that "made the IP fail".