before i get the the problem, let me tell you what i've done so far...
i've doen the tid mod and the tb mod all prior to droping in the s5 jspec engine in my 87 t2 and ever since, my idle has been driving me up the walls....i've checked and adjusted my tps, idle, timing, bac, and everything that deals with the idle and then re-checked and re-adjusted them all over again just to make sure....but the problem is still there...
so here's the problem....

the idel is fine when the engine is cold...but as soon as it warms up..the idle moves up to 1.5k rpm and do matter what i do, it won't come down...unless i turn off the car and turn it back on then it will idle @ about 850rpm....but will jump back up to 1.5k rpm as soon as i give it some gas....

that's not what's bugging me....after the car is warmed up...when i take it for a spin (even if it is just around the block) the rpm will bounce between 1.5k - 2k like it's "searching" for an idle....if i don't drive it and just rev it, it's fine...

i'm at a lost...any help will be much appreciated...

thanks in advance....

------------
mods:
-s5 tii jspec
-s4 reprogrammed ecu
-tb
-tid
-everything else is stock...

 

Check the clutch switch. Its under the dash, and gets pressed in when the clutch is released.

 

what exactly am i looking for???
and do you have to press in the clutch to start the car? cause i can just start it without pressing in the clutch...

 

bump...bump...

 

Check for vaccum leaks anywhere below the throttle plate. I remember reading somewhere that you have to plug something off when you do the tb mod. Excess air slipping in can raise your idle I guess.

Basic tune ups are also a good place to start. Spraying carb cleaner everywhere will help you find a leak. You can also try an unlit propane torch.

 

it you give your car just a tiny bit of gas say, bring the rpms up to 2500 and hold it there. if it bounces from there then your tps is most likely the culprit. Did you adjust it with the two lights? lightbulbs burnt out a piece of my ecu so be carefull doing that.

You can acurately adjust your tps when the car is cold if you remove your intercooler and prop up the lever touching the water thermo wax. This is actually a much better method then relying on the engine to be very hot, cause it does cool down quickly.

 

if you are looking for vacum leaks be carful on the type of carb cleaner you use, some of them will eat the apex seals

 

hey man, its not your tps, or any of the normal things if you adjusted everything right. its the fast idle cam screw?(i think thats what its called) , its the screw right underneath the intercooler, right by the firewall side dashpot, right next to the intake butterflies. after i did my tb mod, i had the same problem you did, the idle would be fine, then float up to around 1.5-2K. after you do this it should be fine. adjust that counterclockwise, and see if it goes down. also check that your throttle cable is not too tight, and adjust your idle mixture. to adjust the idle mixture, get your idle to 750, then turn the variable resistor(the little switch right by the air intake, that has a screw slot, and a r and l on it) turn it to the clockwise position until your idle is at the highest point, then adjust the idle back down to 750 via the BAC, and the fast idle cam screw, then counterclockwise untill the idle gets down to 730, then clockwise again untill its back at 750. i know its kinda weird but it works!





man im the idle wizard, nice a low 750-800, i love it!

 

Care to elaborate on what brand of carb cleaner will be fine for use of aluminum and steel in the carburator, but can eat through steel apex seals while the engine is running?
I've never heard of such a thing, and it makes absolutely no sense.
Sean Cathcart

 

Pass it dude!!!!

 

certian carb cleaners if you rread the back will say do not use on rotary engine because it will eat the apex seals. i have seen one that said this and a mechanic freaind who races first gen 7's has had it happen to him

 

Can you name me these brands? I'll pick some up and test it out. I am curious to know how a carb cleaner can be fine for use in the steel of the carburator, and in the piston rings, and yet kill the same steel used in apex seals.
Sean

 

The carb cleaner warning might be directed at the early 10A's and such that came with carbon filled alumimum seals(modern race seals are made of the same stuff). I imagine the carb cleaner might attack the carbon in the apex seals. But as for the steel seals, somebody is smoking some good ****. Ive used carb cleaner on steel apex seals many times, and no problems.

The clutch switch is NOT the ignition cut switch. There is another one. Look up under your dash, you will see 2 clutch switches. The one closest to the firewall is the ignition cut switch, and the other one is the one you want to test. If that switch is bad, it will cause a high idle that you cannot adjust down, period. That fixed my problems.

 

thanks all...for the help...i'll be doing some tinkering today...so i'll let you know what's up...

 

That sounds like a good fix. My problem is when my car is warmed up....the idle goes up and down slowly between 600 to 900 rpms. Lately I have been using my SAFC to compensate. -15 at 1000 rpms seems to smooth out my idle. Should I tinker with the screw on my air fuel dra-gon-lee?

 

That sounds like the tps to me, going up then down... make sure your tps is all good b4 you adjust anything else.