Xj hard start and stall cold

[werd]

Originally Posted by Shiggins

So it's definitely better now. It still has a rough idle at start but no stalling. I might need a new iac soon.

Resetting the computer could help?

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The IAC has what is called a stepping motor. Power from the ECM adjusts it in and out a little at a time and locks it in position until it needs to be adjusted again. When you turn off the motor, the ECM holds the position of the IAC in its memory. If for some reason it is not in the position that the ECM expects it to be, this may cause problems. Resetting the ECM will clear the memory and the next time you switch the car on it will also reset the IAC.
The IAC also gets data from the TPS. Reset will help here too.

I'm not fixing it, I'm improving it!

[Roler]

IAC, TPS and throttle body valve could all be involved. I'd start with some free stuff first.
If not done yet, clean throttle body/valve especially where the valve "sits" at idle (is good maintenance anyway).
For correct running of engine, fuel/spark/timing all need to be there. So also think about fuel delivery: could be verified with a reading of fuel pressure at cold start up. Re/Adjusting the throttle cable is a free fix which has solved a few issues for Xj users.
Testing the TPS is best done with an analogue multi meter, because it will give you a nice visual on the meter 'sweep'.
All the above can be done at no cost before any parts are (to be) purchased

pS: rough idle at cold start up could also be leaking fuel injector(s). The idle should usually clear out after a few seconds of running as the engine clears the excess fuel.

[ab56452001]

We just tested TPS .8volt at rest and gradual sweep up to 3.8 volts full throttle ,there was 4.9 volts incoming . Pull of thermostat housing temp sensor , smelt fuel , but it wouldn't start , ill try cleaning Idle control valve next . I did have a fuel pressure tester, some ARS@#@E never returned it ! .

[werd]

Originally Posted by Roler

Re/Adjusting the throttle cable is a free fix which has solved a few issues for Xj users.

How would you do this?

I'm not fixing it, I'm improving it!!!