It accelerates and decellerates between those rpms. I had the intercooler off to install a SS clutch line and adjusted the TPS sensor (was at 2.8k ohms) and dashpot while I was there. Also, there was a lot of slack in the cruise control line so I fixed that. Then had just water in the radiator because of an antifreeze change and started it up. Then it started doing that after it warmed up, what could be the problem? Ran pretty good with the TPS the way it was, just missed a bit, heard it could be because of that. Does the BACV need actual coolant/water mixture to operate properly?

 

Are you saying, it will only idle between 2500-2700. If so, go back and check all your vac lines, and every thing you did. Could have left a hose off or something.


91 na
intake, exhaust, S-AFC

 

Yeah it isn't steady either it accelerates to 2700 then lets off to 2500 and then keeps repeating this cycle. I already checked those and I didn't miss any.

 

I dunno, all I know is that idle is wayyy too high. Mine is high at 1500-2000. Mine doesn't move too much just depends where it wants to stay at. I heard its supposed to idle at like 750 or so. Never saw that though.

 

Something in your motor is not telling the rest of the car that the car has warmed up. Whatever controls the slow and steady rpm drop from startup 2k-3k to 1200 then down to 750. Thats how it goes on mine.

 

Anyone know what could cause this? Thanks.

 

So you had your intercooler off eh? Adjusted the TPS while it was off did you. And you thought you would'nt be punished! Ha! HUMOR. Now seriously, when you did the adjustment on the tps, was the engine thoroughly warmed up. If not that could be the problem. There is a thingamajig called a thermowax on the aft side of the throttle body that works in conjunction with a fast idle screw and a cam and roller. If the thermowax is not heated up the cam will not fall off the roller and the tps if set at this moment in time will be incorrect. That's my first wildass guess as to what could be causing your new problem. Its a real good guess if indeed the engine was just warm.

 

I'll check that tomorrow, was warmed up but maybe not all the way. It idled dead on at 750 before the other day.

 

I fixed it, almost too embarressed to say what it was, but I will in the slight chance someone else has the same thing happen. Even when tight the cruise control cable had more slack then the book called for (was way loose before) so I tightened it and didn't reliaze it was opening up the throttle some. Loosened it up and now it runs fine. It still is about a half inch or so from where it was so it should make a big difference.

 

That is pretty high, Ryde. Mine idles perfectly, no lopes or anything. Check your vacuum connections, and then warm up the car and adjust your TPS if needs be.