Stumped: High Idle 4ksq

[Shayne]

Please respond direct to me.  I have mail delivery turned off, so I won't
see responses.  Thank you.



Problem:  4ksq idles high when warm or cold.  1200-1700.

Checked:  For air leaks, set timing, checked differential pressure
regulator, pressure temperature sensor, CO levels, ISV cleaned, resistance
of ISV to ECU checked, duty cycle, WOT, closed throttle position sensor, all
ground wires, fuses and throttle plate adjustment.

Replaced:  cap, rotor, plugs, fuel filters, air filter.

Found:  The only possible problems I found is low resistance between the ISV
and the ECU.  I came up with 15 ohms.  Spec is 20.  Not that far off.

I am totally stumped.  Could it be I need to replace the ECU??  I have heard
of the independent ISV control modules on 5000 going bad, but this one is
built into the Jetronic ICU.  So, I must replace the whole ECU.

Anyone have any clues??

Thank you, in advance.




Shayne P.


Oakland, CA.

Audis, MBZs & a black sheep BMW.

BUY ME:  1988 BMW 528e
PARTING:  1972 Mercedes Benz 280 SE 4.5