My other car 88 RX-7 SE, won't idle below 2k until I put the damn automatic in to gear! I have modified the throttle body, so there is no Thermowax or fast idle cam.
Adjusting the fuel mixture does nothing, and adjusting the screw on top of the intake does nothing.
Any ideas?

 

Up we go!

 

There is a pressure sensor up by the airbox. If you have a leak anywhere between the airbox and intake, thats your problem. Make sure the air hose is sealed and all the bolts are tight.

 

When you did your throttle body mod, did you remove the BAC or the other air sononoid? If so, did you plug the holes in the intake manifold? If not, make sure the hoses to those guys are hooked up. Otherwise the engine has a place to suck air in. Could also be a bad BAC valve that is stuck open.

If the BAC is still on, did you disconnect the water lines to it? If so, the BAC isn't getting the heat source it is used to and so it might be staying open like it is in warmup mode. I would disconnect the electrical connector to your BAC if you still have it.

Other than that, jus make sure you dont have any leaks anywhere. If you do, you might be able to hear them hissing.

 

when my auto would idle at 2k rpms it was because one of the nuts on the intake was loose, tightened it and viola, it was gone idles perfectly now. if you check all of that and it doesnt help post again, ill think of more

 

Replaced BAC. Made sure all bolts were tight on throttle body. Checked TPS.
Still idles at around 2k and bunces when you put it in to park.
It bounces between 1500 and 2000 up and down. Up and down!

 

I just adjusted my throttle stop screw and my car does the same thing. Starts up at 3000 RPM for about a half minute, then bounces between about 1100 and 1600. I backed off the stop screw and readjusted the TPS, but I broke a hose nipple off the damn bypass solenoid valve when I tried to replace the intercooler, so I can't know if I fixed it yet. Check TPS, then the stop screw....?

Kevin

 

Had the same problem when I put in my new motor. Wouldn't idle at all, and when it would idle it bounced around like you said. Put a stethascope under your intake. If you hear hissing there is a vaccuum leak. Mine was sucking air around the injectors( one wasn't seated). Hope this helps.

 

Found a Bypass Air Solenoid Valve to replace my broken one (see earlier reply). I then readjusted the throttle stop screw and then did a TPS readjustment. I no longer have the high idle at startup, and the bouncy idle is GONE! I would pull the intercooler and check your throttle stop screw, then recheck TPS.

Unfortunately I still have one serious problem left (the one that got me started looking at all this mess!). Look for a post soon

 

glad you found the problem. I wish more people would post follow-ups. Good luck to you in diagnosing the other thing. What was it again?