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re: 90 idle surging

>From: randrews@post.cis.smu.edu (Robert Paul Andrews)
>Date: Mon, 11 Mar 1996 12:43:44 -0600 (CST)
>Subject: 90 idle surging
>My 88 90 has an idle surge that is intermittent.  It will surge to 1400
>then drop to 1100.  Any thoughts ideas?  Thanks

Welcome to the Club!!  Mine that intermittently for 8 years now.  I 
believe it is a loose connection/wire/sensor in the FI system, but have 
not been able to isolate it.  I *think* it may be the ISV (idle 
stabilizer valve), becuase whenever mine has this problem, the ISV no 
longer recieves a feed from the FI comptuer.  

FYI  mine developes this problem primarily when *hot* (like in Phoenix 
on a nice sunny - 105F+ day).  Turning the ignition off for a second or 
two and restarting the car cures the problem for a few seconds to the 
rest of the day.

Let me know more specifics on yours - temp, does the engine lose power? 
(mine does), etc.

Do we have any FI experts out there who can help? 
I have had dwell and milliamp meters on the ISV and DPR (Differential 
Pressure Regulator - adjusts mixture on the FI unit).  Only thing I 
found was that the ISV signal stopped whenever the problem occured.

Allan Morris
Phoenix, Arizona
H:  allanm@primenet.com
W:  amorris@brwncald.com
1988 90Q