I'm out of ideas, guys. (Truck runs like crap no matter what I do).

[hawkeyez71]

had the same thing happen, ran fine over the weekend parked it then monday ran like crap! Took us like 15min. to do and that was our first time.

 

[VorTecxas]

To be honest, I have no clue how. I saw the recent write up, but it didn't really make sense to me.

What didn't make sense. I'd like to fix that so no on else gets confused. And on your fuel pump note, that you never get below 1/2 tank, that is VERY bad. That creates moisture buildup, which fails pumps faster than nothing at all. I am an Underground Storage Tank inspector and I know EXACTLY what is going into your fuel tank at the gas station, and it's not just fuel. See my rant (with facts to back it up) on that here, post #6 - http://www.gmt400.com/forum/showthread.php?15810-Engine-is-slow-to-prime&highlight=VorTecxas

 

[TylerZ281500]

i dont understand timing degree increments.

 

[heavychevy98]

Degrees of timing refers to when the spark plug fires in degrees BEFORE TDC. 0* would be firing the spark plug exactly when the piston reaches its highest point, 30* is going to fire the spark plug slightly before TDC, which sounds counter-productive but this allows combustion to begin so that it reaches maximum cylinder pressure. Ignition isnt instant, the faster an engine is spinnig the sooner it has to begin combustion in order to reach maximum effect at TDC.

But back to the degrees, the crank rotates 360* so if ignition occurs at 30*, then the plug is firing at 330* assuming TDC is at 0*/360*.

 

[RHamill]

I'm willing to bet its fuel pump or ignition timing.

What RPM does it idle at?

 

[jdyates]

Well guys, got a reading on the timing. She's right at 0*. And wasn't bouncing around or anything, stayed there the whole minute or two i had the light on it. This was with the spark control bypass wire disconnected.

Ryan, usually at about 500 when its warm and not acting up (idling up and down).

Should I try advancing it a little? I hear alot of people with TBIs advance them like crazy to get better performance.

 

[Vortec Lover]

Well guys, got a reading on the timing. She's right at 0*. And wasn't bouncing around or anything, stayed there the whole minute or two i had the light on it. This was with the spark control bypass wire disconnected.

Ryan, usually at about 500 when its warm and not acting up (idling up and down).

Should I try advancing it a little? I hear alot of people with TBIs advance them like crazy to get better performance.

my dad advanced it on his '94 350 burb and did an intake lid flip- got 17 mpg with 800 pounds in it

 

[tscherbi]

You should get a fuel pressure gauge and drive around a bit to see what your fuel pressure does when the problem acts up. Check your ground cable on your pump as well

 

[jdyates]

You should get a fuel pressure gauge and drive around a bit to see what your fuel pressure does when the problem acts up. Check your ground cable on your pump as well

Which ground is for the pump? The one on the frame right behind the tank had corroded and broken apart awhile back, but even with it all messed up it ran fine, just had no taillights lol. And yeah, i need to get a pressure gauge on it quick.

 

[X-Cutioner]

im going to throw another thought into this thread
check the injectors
my dad has an 89 with a 350tbi in it and he had the injectors start to fail in it. it started with the computer going bad causing the driver side injector to quit firing randomly, then the injectors began to leak, then a head gasket blew. We messed with that truck for over a year and during that time the injector wireon the driver side got pinch which burned up the injector driver circuit in 2 more computers that we had before we had found the bad wire. after all that the iac valve started to give us fits and would set the CEL but after driving the truck for about a month it finaly cleared up and has been running great since then.