Rodent Infiltration - Now Very High, Hunting Idle

[klaatu42]

Hello. Like a total moron, during a house move I accidentally left 11633's driver door open in an outdoor car shelter, got distracted, and did not return to it until the next day. In the meantime, a very industrious chipmunk made quite a nest in the storage compartment behind the driver seat. Coincidentally, or not, the car now has an insane (as in high revs) RPM range hunting for idle, to the point where I had a hard time getting home from the first event I took it to afterwards because it kept surging forward when attempting to stop at stoplights.

Is there an obvious culprit I should look for under these circumstances? For example, is there a certain wire in the box above which, when chewed, might cause this kind of result? I find it to be quite coincidence.

Incidentally, 11633 is an 82 automatic running open loop. It also has aftermarket cruise control (which is the first thing I'm going to disable to test, of course).

Any leads greatly appreciated!

[TTait]

Obviously start by looking for any physical damage, to either wiring or even a vacuum hose from the critter. Deal with that first.

I had some high idle issues when light green wire from the throttle switch and temp sensor to pin number 7 of the lambda controller was damaged. Damage could be in the engine compartment, at the bulkhead, or from the bulkhead to the lambda controller. Don't recall if the wire was broken or shorting. You can try disconnecting the wire at the WOT switch (if you have one?) and at the temp sensor (screwed into the right side cylinder head assembly.)

With the engine running, try unplugging the frequency valve, see if it slows. That might help isolate the problem.

If not, see if the throttle return spring is doing its job, and if the throttle plates are fully closing.

If that's not it, you may have a vacuum leak?

[klaatu42]

Well, just as mysteriously as it arose, it went away. I haven't been able to reproduce the problem in days. I wish this comforted me, but of course I'll just be waiting for it to rear its ugly head again any time in the future!

Thanks for the reply, though.

[PJ Grady Inc.]

Well, just as mysteriously as it arose, it went away. I haven't been able to reproduce the problem in days. I wish this comforted me, but of course I'll just be waiting for it to rear its ugly head again any time in the future!
Thanks for the reply, though.

Do a visual check of the wiring above the stowage box in the ECU compartment. You can access it by removing the carpet and wooden panel as you would on the other side to check the relay compartment. Of particular interest would be the wires feeding the black ICU on top of the metal plate as that controls your idle circuit. It's possible that insulation has been chewed off by Alvin or his brothers leaving you with an intermittent ground fault. If the RPM was stuck around 2500 that would indicate a problem in this area.

If there is no issue there but 2500 RPM is the magic number it may be a loose or chewed connection at the idle thermister under the intake manifold.
If the problem is there you may have to remove the intake manifold if there is rodent damage.
Rob