stalling even worse now.

[cyberpine]

Many months ago I posted this.

http://67-72chevytrucks.com/vboard/s...d.php?t=366699

Well the truck has been in a shop a couple of blocks away for months now. I've be stopping by and started her up and driving her around. The day I took her into that shop It stalled so many times I had to have it towed in. Anyways, along way we've change a number of things.. Gas , fuel filter and gas tank, fuel pump, tbi intake gasket, added manifold sealer, had to change the distributor.

The truck starts up great every time and drives hard and fast for about a minute then dies. If I leave it idle, it does basically what's in that video (fluctuates) then dies.

The mechanic gave up on it .. he said that if it where his he would pull out the TBI and put in a 4 barrel Holley Carburator.

Thoughts about that? How simple to do the swap?

Question, can I put in a Holley Carburator and keep the Edelbrock intake manifold? The current TBI is an after market Holley currently. Details about exact parts in link on my signiture.

update: someone suggested i uplug the EGR to see if idle fluctuation would stop, and it does, but then never idles and seems to run way too rich. If this is true, any chance my TBI or the injectors themselves are still failing. BTW, when removed the gas tank the fuel did not look or smell like gasoline, it had a oily feel to it. I now have a fresh tank, fuel filter and super unleaded gas.. still stalls.

Thanks.

video when truck was at least running:

http://www.youtube.com/watch?v=lg4cCLDsFtY

[tazman87]

could be a vacuum leak or a timing issue.

[TimQ]

I just tracked down a vexing 4-year long stalling/starting issue to the Engine Spark Control module. Worth a look:

http://67-72chevytrucks.com/vboard/s...d.php?t=419212

[72lb4x4]

Just guessing here. My old vehicles are all too primitive for injection.

If its injected, it's got a computer that should be saying something about what it thinks is wrong. If they've been read and things checked, bad connections make the computers crazy.

Go through and clean ground connections and the connections in connectors, as well as damaged wiring.

[tucsonjwt]

Based on what you said about oily fuel in the tank, could someone have accidentally (or intentionally) put diesel in your tank? Do you have any of that oily fuel left around to check? Also, if the truck was not run for a long period of time, the fuel can varnish up and clog the fuel injectors, etc. Might need to clean/replace the entire fuel system. Just a thought.

[cyberpine]

Thanks guys!

Update: My new mechanic spent a few days with the truck. He took off the throttle body and he says found junk he had to clean out. He said injects are spraying clean and consistent. Keep in mind I now have a new tank and fuel filter and fuel pump.

He now says the it's idleing beautifully without stalling or flutuating! However when you hit the gas it instantly dies.

He's a mobile mechanic that works from home and no way get any kind of readings on the engine, but thinks it might be the TPS (Throttle Position Sensor).

Thoughts?

[GmtGmt]

you say it has a Holly TBI?

i would get a Orginal GM TBI and try that. didnt RandyP have problems with his also?
also the

also replace the Engine Spark Control module heard they are a problem also

[RandyP]

Mine (Holley TBI on a new crate engine) would start and idle for about 10-30 minutes, and then kick down to like 300rpm and try to stall out. It would also not come to a stop light and idle, it would die out.
My GM mechanic replaced the TPS with a new OE sensor and then set the idle and timed it, the correct way. Now mine runs fairly well, still has a very low idle at stop lights, but just a little gas pedal (I'm talking rest your foot on the pedal at most) and it never dies out.

Most of my issues are from my engine though, seems the cam in the crate motor I picked does not do a very good job of creating vacuum, which causes the MAP sensor to freak out a lot.

[cyberpine]

Originally Posted by RandyP

Mine (Holley TBI on a new crate engine) would start and idle for about 10-30 minutes, and then kick down to like 300rpm and try to stall out. It would also not come to a stop light and idle, it would die out.

That pretty much describes my 87 right now.

Nice truck! If I can ask (private if you like), what did you pay for parts and labor? How long have you had the truck? Daily driver? Is that a 305 or 350? I love the stock rims painted like that. If they were 15x10 I would keep mine. If I can get her running good I've got a set of 15x10 deep aluminums I'm going put in with 33x12.5 after some wheel well cutting I plan to also do.

Thanks and best of luck.