washed engine

[jjfitter]

I washed my engine and everything was good that day but next day idle went up to 1700. When I unplugged the TPS it went back down but then readjusted itself to 1700. Where could I have gotten water that might cause this?

[jjfitter]

It's an '87 L98

[Lone Ranger]

Ask this in C4 tech, and include a more descriptive subject line. Will get some answers probably. I don't know the answer. L98's are usually less risky to put water on than LT1's.

[DOCTOR J]

Suggest putting a scanner on the ALDL port. There are only about 3 signals coming from the engine bay
that affect idle RPM:


1. If the CTS reading is -40 at start-up, you've open-circuited the CTS thermocouple. Repair or replace.

2. If the 5-wire(?) connector at the distrib is hosed, ECM will (perhaps) see an erroneous RPM signal.
Replace the wiring pigtail.

3. If the IAC motor or connector is hosed (or if you created an intake vacuum leak) the ECM will be unable to
maintain the idle speed set-point. That will be apparent from the ALDL datastream.

HTH