Code 51, Idle at 3K rpm, TPS?

[87silverbullitt]

Hi everyone, just trying to figure out whats going on with my supra, aka poopra right now. I know its throwing a code 51, and since i have my air conditioning system completely removed i know it throwing it because of the TPS.

I replaced the headgasket on my car about a month ago and haven't had it on the road since. It was running and idling fine before the headgasket blew, its just ever since i put it back together. Im 95% sure I installed everything correctly on the car. Im confused because i never even touched or removed the cps when replacing the headgasket and now it 'seems' to be failing all of a sudden?

Whenever i start my car, at this point, the idle will just shoot up to 3 grand and sit there. Before that the idle was jumping all over the place, anywhere from 1k to 3k rpm kinda as if the timing was off however i had a friend come over who also owns supras and we checked and set the timing properly on the car at 10degrees BTDC.

Can anyone try to guide me in the right direction?:1zhelp:

 

[Nick M]

Throttle cable stuck?

 

[hvyman]

If the a/c button is pressed the 51 will come on with no a/c. If not your tps is bad.

 

[Supra0089]

I had similar issues...turned out the water temp sensor connection was shorting (2 wires touching at the sensor) thus shorting out the circuit...which includes the TPS and will throw a code 51. The TPS is kind of a pain to install/calibrate...I would check other things first. There is a way to dx the TPS...you have to look it up in the TSRM and test the tolerences under various throttles. Make sure you use an analog volt meter while doing this...I guess a digital one will give you false readings.

As hvyman said...it could simply be your a/c throwing the code...but if you're having throttle issues...and idle issues it leads me to believe its TPS related...whether its a short in the circuit...or the TPS itself. The TPS is a wear item...so it has to be recalubrated or replaced after a while...but we are talking a long while...

 

[Nick M]

51 isn't the source of a 3000 rpm idle.

 

[jetjock]

What Nick and hvyman said. And don't be setting timing with a code 51 until you know what's causing it or you could make things worse. You'd think a friend who owns supras would know that but apparently not...

 

[87silverbullitt]

As hvyman said...it could simply be your a/c throwing the code...but if you're having throttle issues...and idle issues it leads me to believe its TPS related...whether its a short in the circuit...or the TPS itself. The TPS is a wear item...so it has to be recalubrated or replaced after a while...but we are talking a long while...

I dont have Air-conditioning anymore, and the button on the dash, regardless of still being there is always left off. But yea i do think its the TPS as well. Im going to find out tomorrow hopefully.

 

[87silverbullitt]

What Nick and hvyman said. And don't be setting timing with a code 51 until you know what's causing it or you could make things worse. You'd think a friend who owns supras would know that but apparently not...[/QUOTE

I never mentioned the code 51 when we timed the car because at the time i didnt think it was a big deal until i realized it still wasnt running properly after it was timed right. We had the car running nice at one point and then he gave it a couple of revs up to around 4k rpm and then on one of the revs it just stuck high for some reason. The idle didnt want to come down ever since then. Even when i start my car from dead cold the idle will jump right up to around 3 grand, hold it there for a second, and then bounce around everywhere.

 

[hvyman]

Sounds exactly like a bad or misadjusted tps .

If you push the a/c button at all with no a/c it will throw the light.

 

[Devin LeBlanc]

Idle needs to be at 650 rpm to set timing properly anyways.

 

[3p141592654]

A shorted coolant sensor will set a code 22, not 51, and will not impact any other sensor.

Your car must have a big metered air leak to hit 3000 rpm with the throttle closed. I'm with Nick, check to make sure the throttle isn't sticking open. Its the most obvious thing to start with.

 

[jetjock]

Or it might set a 22

 

[3p141592654]

Should not go from memory!

 

[87silverbullitt]

Hi guys, found my problem, the maf sensor on my car is f**ked. When i leave the maf plugged in and the cars running the idle shoots up to around 3k rpm. When i unplug the maf the idle drops down to where it supposed to be at, around 900 rpm. Code 24, trying to find another maf today.

 

[hvyman]

If you unplugged it and then checked codes 24 would pop up from unplugging it.

 

[Nick M]

Should not go from memory!

I swear I can't remember anything anymore. It must be the Diesel fumes.

 

[Nick M]

A shorted coolant sensor will set a code 22, not 51, and will not impact any other sensor.

I just saw this one on another forum today. I said to look at it because they share E2 ground.

 

[Moy]

would code 51 pop up if I didn't touch the a/c button but have completely removed the a/c system from the engine bay?

 

[3p141592654]

The code 51 AC input is from the HVAC electronics behind the dash. The stuff under the hood doesn't matter so much. So, if you still have the HVAC controls and the AC amp and servo unit installed then the AC button on will cause a code 51, even if the compressor is missing.

 

[hvyman]

Easy to check to. Clear the code. Press the a/c button with the car on. then it should throw the code fairly quick.