85 Vette Idle Problem - HELP!!!!

[Volker]

Hi Steve!

Perhaps it won't help you but (who knows) I've seen similar problems with 
my Isuzu V6 engine.

One year ago an idiot put a mixture of water and sugar into my (not locked) 
tank. I've emptied the tank and everything seemed to be fine. Half a year 
later I've had problems like hard start symptoms and an incorrect and 
unstable idle (from 400 to 800 rpm up and down within seconds).

This machine has a TBI unit and when I removed the TBI from the engine I've 
seen channels with dirty, a little bit oil and some sugar crystals. Also 
the IAC channel has been dirty. After cleaning the idle was fine again.

At the very first time after looking at these symptoms I also suspected to 
be a bad sensor  but it wasn't so.

Perhaps it won't hurt to check all vacuum lines etc. (as long as your car 
has a TBI) - just my 2 cents.

HTH,

Volker

At 2001-07-26 20:52, you wrote:
>HELP!
>
>I had my 85 Corvette motor rebuilt and the builder put in a slightly?
>different CAM.  Since the install (2 years ago) I can not get the car to
>idle.  It surges between 450 to 800.  I have replaced injectors, O2, EGR,
>IAC, (everything except MAF).
>
>I am working with a Chip company to get a chip to fix the idle, my
>assumption is that it is because of the CAM, however, we have not had any
>success getting the Chips to work.  During the process my original chip lost
>a pin, so now I have a new problem of not having a working chip at all.
>
>1.  What can I do to get a cheap replacement factory chip, I have 4-5 EPROMs
>that do not work (from the chip co.).  OR - where I can get the original
>code for the factory chip, I can have the chip company burn it onto an
>EPROM.
>
>2.  What can I do to make this car idle?  Has anyone seen this problem
>before and have anything that can solve it.
>
>The only Other thing it may be is the MAF, it set a MAF code about 1.5 years
>ago, I reset the computer (disconnected gnd) and I have never seen the code
>again.  So I assumed it to be an intermittent problem, maybe a bad
>connection, etc.
>
>The funny thing about this is I am a crew chief for a Drag Car, we run a Pro
>5.0 Mustang with a 302 - single turbo and run in the low 7's at 195 mph in
>the quarter mile.  I can tune this car no problem, but the factory stuff has
>me stumped.
>
>Thanks.
>
>Steve F
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Volker    /   Volker at VWSoft.com

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