Car came home and would not idle, 2 weeks previous I had replaced the fuel pump. Thought it might be fuel filter, no difference. Thought TPS had similar problem on a 302 Ford and that fixed the Ford not the Land Rover. Then I found this web site. Cleaned the air bipass valve, some junk, not too, bad cleaned throtle body. Now I have a idle that starts 1500 and climbs to 3500 and stays. My son works at a import car parts store, so I get new valve and install. Idle drops back to where we started. Removed new bipass only to find plunger still in hole. Put original in and idle goes right back up. Should I find a better valve (he had two to chose from). I can't seem to find any vacuum leaks, but a 3500 rpm its hard to hear any thing. Also at the same time I did the fuel pump I put on a new mass sensor. My wife said it had never run so well. The nearest dealer is now 4 hours away. Thanks for any input.

 

YOu dont say but it has to be a DI because you repalced the fuel filter and DII's do not have one.
Since you replaced the TPS it needs to be calibrated.
You either need the dealer or a mechaninc with a TestBook computer.
You can cheat and loosen the 2 screws that hold it on and with the engine hot and running GENTLY tap the TPS until it idles normal.

 

Thanks I'll head out to the garage.

 

Tried loosening TPS as suggested and tapping, this time I'm back to no idle.

 

Ok, then your stepper motor is bad. Also known as the idle air control valve.
It feeds the engine air at idle, if it does not work then it wont idle.
Also make sure that all the air passages that it goes to are clean.

Re-read your original post, did you install a new stepper motor?

 

I installed a new IACV and it came apart. In trying to diagnose the problem I removed my new IACV and when it came out the plunger had pulled out of the housing. I then put the original back in and idle went back up. Tried loosening and tapping only when I went back out to garage the idle is back to too low. Apparently I'll have to drive the 4 hours to the Land Rover dealer.

 

If I have IAC then I don't have a stepper motor.

 

An IACV and stepper are the same thing. I replaced mine 6-8 months ago and it idled high like mad. A 1/2 hr trip to the dealer and an ecu re-set had it goin good as new. They have to erase the adaptive memory for the stepper motor, as it(ecu) thinks it has the old one in there. Unfortunatly, the only way to erase the memory is either a LR Dealer, or some one that has specificaly a Testbook or T4 computer.

 

Update to my idle issues. New Lucas IACV installed, still have racing and then no idle. Drove 4 hrs to Land Rover Dealer and had system reprogramed. Picked vehicle up and it idled fine, but when I left it died about a mile away. Came back and tech removed the engine control module. The module is rusted, now a couple of techs and the service manager are gathered around. Dealership does not have a new one and it lists for $3100. We take it apart and clean all the rust out of module. Car now runs fine. Leave dealership and head north, the first stop no idle. Now I have the car back home and it idles fine when cold, but dies when warm. I'm going to put on a temperature sender and I've found a new module for $550, but is there something else that might cause this?

 

The ECU is adaptive (on the DI, anyway)
If you replace any poor performing part, it will take numerous drive cycles to settle down.

This is aSSuming everything is operating properly.

Just a note, when I replaced my IAC(stepper), some times mine would idle fine for days, sometimes it wouldn't idle down.

I got tired of it and pulled my flex to throttle body connection & made/installed an alum blankoff for IAC opening inside throttlebody.

Problem solved, it's been over a year.

I'm not promoting to do this, but it may be a test to see if it's ONLY your IAC.

Guys are out there using Jeep, camaro and other $40 IAC motors sucessfully so don't give up.

Maybe the rust caused your ECU to drive your IAC crazy. (it's simply a pulsing motor that drives the plunger in/out depending on conditions) - a/c, cold temps, rev on strart, etc.

luck,greg