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quick question- what is normal idle rpm?

Impatient are we? Was this a life or death question?

All of my XJ's have idled right at 750-800 or so.
 
Slow answer, LOL, :laugh:

750 RPM. Nothing wrong with about 650 to 800 for a manual.
 
mine idles between 1000rpm and 1300rpm depending on what kind of mood it is in. and i have checked out tonnes of emmissions stuff like sensors and vac leaks.... what the hell
 
thanks, but i've replaced the CTS, MAT, O2, Knock sensor, MAP, all the vacuum harnesses, adjusted the TPS, cleaned the Idle stepper motor. checked over for vac leaks. I am getting really sick of this jeep. i've put over $500 into just trying to fix this high idle problem and get some decent gas mileage already.:bawl:
 
Mine (90) idled at approx 330 RPM's (very low) for a long time. It still ran fine, and never died. The problem was only that at idle it was idling too low to keep any current pumping (from the alternator). I however was able to get it to idle at a consistant 750 RPM's (which seems ideal to me).
So i would say anywhere between 500 and 750 RPM's is OK. Defineitly no higher or else it would really want to pull while braking.

This information is givin for the RENIX era XJ/MJ's. Its probably different for latter years (91+).

Hope that helps
 
mitsumotors said:
thanks, but i've replaced the CTS, MAT, O2, Knock sensor, MAP, all the vacuum harnesses, adjusted the TPS, cleaned the Idle stepper motor. checked over for vac leaks. I am getting really sick of this jeep. i've put over $500 into just trying to fix this high idle problem and get some decent gas mileage already.:bawl:

Sounds like ME!!!!!:wave1:

But I finally solved mine when I ran out of parts to buy new and replace. All it took was cleaning each and every bloody ground wire on the battery negative post, the side of the block near the oil filter and oil dip stick the TWO on the firewall, and the the one on the rear drivers side of the engine head. I also had to run a new ground wire from the TPS gound wire straight to the battery negative post (It was easier than tracing the ground wire trhough the harness to find the weak connection).

In my case the variable idle was due to a dirty loose ground connection at the engine block near the oil filter, As the engine moved, heated and cooled, the ground resistance changed, which changed the TPS idle voltage, seemingly randomly. The TPS voltage always tested OK at idle, but I had never tested it when the idle was high!

Once I fixed the ground problem, I had to readjust the TPS idle voltage because the good ground had moved the TPS standing idle voltage. I also had to disconnect the battery to clear the Renix TPS idle voltage Memory, and it has run at 750 rpm, dead on ever since.
 
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