NeXJ
NAXJA Forum User
- Location
- Los Angeles
pep boys wanted sixty dollars for a new replacement however - so I opted to see what i could do with this one.
Shesh, that sir is not the droid you are looking for. That is the IAC Idle Air Control valve.
The IAT Intake Air Temp sensor is in the top rear of the intake manifold. The IAT has two pins, it is a variable resistor.
The IAC you pulled is a stepper motor valve.
Google "jeep Cherokee IAT sensor image" for the image and location
The REAL IAT has no bolts, it is a pipe threaded male brass body.
Make sure you reinstalled the face sealing o'ring on the IAT idle control valve properly!!!
Never use carb cleaner on wiring. The IAT has super fine motor wires. Must use an electric parts cleaner safe solvent. Carb clean can strip the varnish off the motor wires and short it out if it made contact too long, like soaked it.
What year was your rig? If Renix 87-90 you must calibrate the TPS output voltage by positioning the clamp down spot precisely ( rotation of the TPS body ). Proper Idle is at 0.82 Volts. 91-01 does not need calibration.
The IAC is not a sensor, it is controller valve to be precise, kinda like the fuel injector valve that controls fuel flow, it regulates the air flow rate but only at idle.
The IAT is a sensor. The TPS is a sensor.
They are all thingies, LOL. or watchamacalits and thingabobs, LOL.
Just for the fun of it, once the engine is off for a minute or more and cold, disconnect the IAC and start it. If the idle problem remains my money is on vacuum leak at the throttle body, injector or intake manifold to head gasket.
With the IAC disconnected the idle should drop as it gets hotter I think, if it changes at all.
incidentally i didn't do this until i had the new IAT - I wanted to test one thing at a time you know... anyway- with the IAC disconnected it behaves nicely and the idle doesn't climb ... hmmm... maybe i should drive it around with the IAC off for the time being ... at least it should be able to get me to the post office without having to turn off my vehicle in the middle of busy intersections!
I forget the story on this, did it ever throw any codes at all?
Is the TPS reading normal resistance at idle, with the power on and engine off? Or has it gone bad?
Is it running closed loop with the IAC disconnected?
What are the fuel trim numbers with the IAC disconnected? STFT and LTFT?
Have you tried disconnecting the battery and clearing any old data in the PCM now that it has a good(?) IAT sensor?
From what you just said, it is not a vacuum leak. This is major progress.
Since you have a 97 rig?, go to ebay and shop for and order a bluetooth OBD-II scanner (about $20 delivered), then buy the apx $5 TorquePro app for your(?) smart phone, and then with both you can monitor if the O2 sensor PCM is working, live data, and you can monitor the fuel trim, engine temp, air temp (it would have caught your bad air temp sensor right away) and so on and so on live engine data!!!!:cheers:
Don't leave home with out it, LOL
I think I'm ODB I though - i'm not sure if i can get that much data (?) - my computer is a '92. The engine is a late 97 but I left all the '92 accessories so that the computer would still work... the only real issue with it was having to tap a new hole in the head for a 92 temp sender...
should i get an ODB I reader? as far as I understood -the 'key switch' trick gives me about as much info? or is that wrong?