jwy

starts up cold runs 30 seconds and then starts idleing below specs,, the only code i get is knock senors, replaced it, runs great in neutal but under load still have timeing knock, replaced egr valve didnt see anything wrong with old one, cant find any vacums leaks, replaced iac valve,still starts idleing low replaced throttle sensor, any body know what else controls the timing or knows what other thing to look at when it dies at idle wont restart unless you do a code check which shows nothing and then it starts back up help jeff

cdru

You might try the Astro forum. This is the Venture forum. Same make, different model.

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Vinyl adds horsepower, right?

Kings-x59

I must've had one beer to many. Could have sworn this was the astro forum.

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'89 Astro 4.3L Z
CFM-Tech power plate
2.5" exhaust, Low restriction cat and muffler
Jet stage I chip
B&M trans cooler

'96 Jeep Cherokee
'99 Chevy Cavalier

Kings-x59

I gather you've checked all the vacuum lines from your post. One other source of vacuum leak is the base of the throttle body.

Have you done the basic tune up stuff? plugs, wires, distributor cap, rotor?

You might check for ignition system arcing. Best way is to pull the doghouse after dark and fire the engine up.

If you are not getting a code, it is most likely vacuum or fuel delivery related.

I went through a long rehab process on my '89 and replaced pretty much every sensor. The one thing that I wish I had done first was to rebuild the TBI. It was incredibly dirty inside. Afterwards the difference was amazing.

Post a little more info. The folks here might be able to help you zero in on the problem before you the shot gun approach that I did.

One thing I would suggest is to get a digital multimeter, and a Haynes manual for your van if you don't have one. The Haynes manual will show you how to test your sensors so you don't replace anything that doesn't need replacing ( been there done that). With the multimeter you can test pretty much every sensor. I got mine for 20 bucks at home depot. Radio Shack has them as well.

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'89 Astro 4.3L Z
CFM-Tech power plate
2.5" exhaust, Low restriction cat and muffler
Jet stage I chip
B&M trans cooler

'96 Jeep Cherokee
'99 Chevy Cavalier

A_Bach

I'm not an expert, but I have looked thouroughly into this, as I had a similar problem, and still trying to fix it.

Anyways, on TBI's there should be an ignition module, that speaks to the ECM (computer) concerning the EST (elec. spark timing). Test that. Also there's an ESC module (elec. spark control) on the sensor tree beside the throttle body. Also test the knock sensor. I'm trying this today. Other than those 3 items, there's the computer, and the obvious distributor parts to check.