Chevrolet Repair: 1993 Astro Van Stalls on Cool Days, chevy astro van, chevy astro

Question
Van,
Thanks for your previous reply. I tried the injector cleaner and it did help a bit, but for the most part the problem still persists as before.

Since the SERVICE ENGINE SOON light goes on for these first 5-10 minutes (then it goes out), I checked the error codes from the ALDL and I get a code 34 (Vaucuum or MAP sensor voltage too low). I took the van to the dealer for a scanner (they did not look inside the engine, only ran the scanner) and it said the EGR valve needs replacing. I don't want to replace the wrong part (EGR or MAP or maybe it's something else...) What do you suggest? BTW, the engine is from 1993 and VIN code W which I think means I've got a CPI model.

The engine bangs a good bit (you can feel it) during this start-up time. I don't think this is related, but when I gun the engine to help keep it going, the speedometer shows that the parked car is moving at up to 7 mph?!

I asked on the chevytalk site (thanks for the link!), but I also thought it smart to hear your opinion since you seem so knowledgeable at diagnosing the most likely source of troubles.

Thanks so much, Van!

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Followup To
Question -
Hi! I have a 1993 Chevy Astro Van which has started to have trouble starting up in the morning on cooler days. The outside temp. is defintely above freezing. On start up the engine cranks well but stalls after a few seconds unless I give it more gas. Even just a little extra gas will help. This condition continues for about 5 to 10 minutes. Occaisonally during this time period you can hear a short banging sound from under the car.

During the day there never is any trouble and the van starts perfectly and runs OK.

When I took the car to the mechanic he could find no trouble, no clogged filters, etc. (but he didn't run a computer scan) and couldn't reproduce the problem by keeping the car overnight because the weather warmed up for a few days! Now it's cold again and the problem is back.

Any suggestions?

Thanks for trying to help!
Answer -
Hello Uri,
I don't know for sure, but you may have a cold start injector on that, and it could be dirty.
You might try running some injector cleaner through the tank if you haven't already.
The banging is probably backfiring in the exhaust system.
There is a site I will send a link for. Go to it, sign up,(Absolutely free), and ask the question in both Astro van section, and engine controls.

You will like that site.

www.chevytalk.org/

Good luck,
Van

Answer
Hello Uri,
Forgive me for not answering sooner, but I was out of town on a firefighting assignment, and nowhere near a computer.

The EGR valve is an item that can, and should be cleaned. If it closes on some carbon, it is the same as a vacuum leak. No need to buy a new one....just remove it and clean it.
The reason it could cause the problem is that the ECM does not use sensor inputs when the engine is cold, therefore will not compensate for the extra air that a vacuum leak would add.
So clean that, but while you are at it, connect a vacuum gauge and see what the vacuum reading is.

Van