Corrado Idle

[Bill Burton]

The idle on my '90 Corrado hovers around 1200 when it is fully warmed
up, cold or whenever. With the A/C on I have seen it climb to at least
2000. I disconnected the connecter going to the idle stabilizer valve
(ISV), and the idle goes down to about 900 RPM. Is the ISV causing
this, or is the ECU sending the wrong signal to the ISV. I have seen
recommendations on www.corrado-club.com to try cleaning the ISV. I will
probably try this next. If anyone has any suggestions please let me
know. Thanks.
Jeff, '90 Corrado

[Alden Cates]

In article <3A132CCE...@telus.net>, Bill Burton <bill_...@telus.net>
wrote:

Clean the ISV and the idle will probably go up for the next couple min then
slowly come back down. If it doesn't, you'll want to try replacing the blue
coolant sensor on the front of the engine, that tells the ECU the temp of the
coolant, whether or not to run in "cold start" aka higher-idle and quick warm-up
mode. The sensor is $14 at the dealer.

Finally, if that doesn't work, there is the odd chance that your idle screw is
slowly working its way out, causing a higher idle. There's a small o-ring that
seals the screw and over time it deteriorates. I had my screw literally pop off
my intake throttle body while driving! The procedure on how to set the idle is
in the Bentley... an indispensable tool for any Corrado owner!

Alden

--
'90 Corrado G60 - Garrett Chip, 68mm pulley, AT SS exhaust,
ISV check valve, 16" Borbet Type Cs
CCA Member #201 http://www.gst.net/~acates

[Bill Burton]

Today I took the ISV off to clean it. It was pretty clean. When I flushed it with
brake cleaner the stuff I dumped out was fairly clear. I tested the ISV by applying
12V to the connecter and it seemed to work. I then blew into one of the hose
connections with the valve disconnected. It let some of my breath pass, and when I
applyed 12V I could easily blow through the valve. I am wondering if when the valve
is closed is it supposed to let some air through or no air through? I hooked the
valve up again and it was the same as before. Also, with the engine running I
disconnected the connector going to the ISV and the idle went down a bit, but after
I played with the throttle a bit the idle was up around 1100 RPM again! With the
connector off, I found the voltage going to the ISV was 12.6V at all times. I am
starting to think that my problem is not the actual ISV itself, but something else.
I could replace the blue coolant sensor, but I don't really want to start spending
money on stuff I'm not sure about. I think I will try that idle screw you
mentioned, but I have a crappy chilton manual rather than the bently so it will be
hard to set. If you have any more suggestions please let me know.
Thanks, Jeff

[Bill Burton]

I figured out what is wrong... the idle screw had worked itself out. You mentioned
that the procedure is in the Bentley manual. Unfortunatly I don't have the Bentley
manual. Could you possible describe the procedure for this? Thanks in advance,
Jeff, '90 Corrado