TPS

[240240]

ok so im sitting in traffic today and I move forward a little bit, take it out of gear to idle, and car just starts to rev really high, and I have a MINES ecu with no rev limiter (sux) anyways, I had to just cut the car off went it went past the 8 grand (240 Tach). Turned the car off then back on, did the same thing reved up really high. turned it off then on again and it was fine? I didnt seem like my petal was sticking

Any ideas?>

[Yellow4g63]

ok so im sitting in traffic today and I move forward a little bit, take it out of gear to idle, and car just starts to rev really high, and I have a MINES ecu with no rev limiter (sux) anyways, I had to just cut the car off went it went past the 8 grand (240 Tach). Turned the car off then back on, did the same thing reved up really high. turned it off then on again and it was fine? I didnt seem like my petal was sticking

Any ideas?>

Bad cable? might be sticking change it out.

[Joe]

before you replace the throttlecable just disconnect it from the throttle body butterfly and see if it still happens.

[eh?]

If the ecu can't read the tps voltage it will idle very high. Where does it normally idle at on your tach?

[Joe]

If the ecu can't read the tps voltage it will idle very high. Where does it normally idle at on your tach?

aint no TPS problem gonna cause the engine to rev to 8000. something else is wrong.

[eh?]

Why won't it on a 240sx tach?. Mine disconnected went to 3k on a Calibrated tach. That's why i asked what it usually idles at.

[Carl H]

a brick on the gas pedal might cause it to go to 8.it has to be catching on something, mine you have to floor for it to go to 8.

[Joe]

Why won't it on a 240sx tach?. Mine disconnected went to 3k on a Calibrated tach. That's why i asked what it usually idles at.

still! even if it is reading high thats a solid 5000+ actual RPM. no TPS problem will cause that. the engine cant physically get enough air without the throttle beig open.

and that brings up another question, 240240 if your tach isnt reading correctly how do you know you dont have a rev limiter? my mines ecu does.

[eh?]

your right i forgot I had the Q45 Tb which had an extra by-pass for idle air. Explains my higher idle. but then again, I wonder how just shutting off the engine fixed the problem.

[240240]

when the car is warm it idles at about 750 rpm. I dont know for 100% that I dont have a rev limiter but what is the rev set on a the rb20---7200? I really need to get my tach calibrated though, I have a HKS SAFR but I dont like the digital readout. Anyways I will check what you guys said and get back to you

Thanks

[goofynick6]

It's a physical thing; no electronics will make the car rev to 5000 rpms w/o a bunch of air being let in to supply the engine. So, therefore you have a throttlebody that is being opened and letting in a bunch of air.

Nick

[Sil240]

No I have actually had this problem with my KA SOHC, one of the TPS wires had come loosewhen i was drivingIt shot up on to the rev limiter, then i shut off the car and then started it again and it still did itThen i noticed one of the tps wires disconnected, put it back in place and never did it ever again

[goofynick6]

No I have actually had this problem with my KA SOHC, one of the TPS wires had come loosewhen i was drivingIt shot up on to the rev limiter, then i shut off the car and then started it again and it still did itThen i noticed one of the tps wires disconnected, put it back in place and never did it ever again

That makes no sense...I've unplugged my tps and done everything imaginable with it and never had it change revs. How does the engine get to 5000 rpm w/o any extra air?

[Eikon]

Could a bad TPS wire cause the TB to open up more?Maybe both people are correct.

ThanksSeth

[eh?]

That makes no sense...I've unplugged my tps and done everything imaginable with it and never had it change revs. How does the engine get to 5000 rpm w/o any extra air?

I don't know about your RB20 but on an RB25 if you unplug the TPS, it will drive the IACV open because the ecu has no reference for idle. But it won't go to 5k.

[Sil240]

I have no idea what happened but i know when i connected that wire back to the TPS it stopped revving.When the wire was disconnected it was bouncing of the rev limiter.If I would turn off the car, then turn it back on it would still rev right upAnd it wasn't that the throttle was stuck, because thats what i thought happened and i checked that too

That makes no sense...I've unplugged my tps and done everything imaginable with it and never had it change revs. How does the engine get to 5000 rpm w/o any extra air?

[goofynick6]

I can see it telling the idle control valve to open up and rev the car up, but revving over 4k rpms doesn't seem right..

[Swedish Mike]

Had this problem once, the TB axle was bent and "the door" got stuck in half throttle.The rpm´s just got higher and higher... Puuh...

/Mike

[240240]

Thanks guys, Gave me some great ideas. Tuesday is my next free day so I will find the problem then and let everyone know. Thanks for all the help

[240240]

By the way, 8000rpm on the 240 tach is really only 5000rpm?

[goofynick6]

By the way, 8000rpm on the 240 tach is really only 5000rpm?

It is probably quite inaccurate by that point, but it should be 5333 rpms, it is 1.5X higher because it has 1.5x more cylinders than stock. You can adjust the blue potentiometer screw on the back on the tach to make it quite accurate though, just need another tach for reference.

Nick