SpeedJunkee

For the last few years my car every once in a while will fire off a P0121 code (TPS sensor). It has never ran any differently, just trips the code. I have replaced the TPS sensor and it still trips the code every once in a great while.

Anyone know more about this code or how to fix it? I think I may have seen P0121P yesterday with the P0121, but could not find what the "P" was for. I have a 95 Z28, with a 24x conversion, and a 58mm mono blade Arizona Speed and Marine TB if it makes any difference.

BALLSS

58mm mono....so have you ever measured TPS VDC with blades full closed & open?

you can do this with a DVM or scan tool

they want to be in the neighborhood of .67vdc full closed and 4.5vdc full open with a "smooth" increase in VDC as the blades open

Often on aftermarket TB's people crack open the blade(s) to get them to idle right...but that FU the TPS volts and brings them out of range which then can throw a code

is this you??

SpeedJunkee

I have not measured the voltage, and will have to check that. I am going to be out of town and won't have access to the car for a couple of weeks. If the voltage shows different than what you posted, what does that indicate? Or how would I go about fixing that?

I have not cracked the blade at all. It does go full closed and full open. This I do know for a fact.

One nice thing about my current setup is that it does idle and drive very nice compared to my previous combo that sounded wicked, but had such a large cam that the idle was hard to get right for the tuner before and the driving habits were not as nice.

BALLSS

If you didn't adjust the TB blade stop screw in a attempt to get it to idle right, your TPS volts should be OK....but since you note a TPS code you should check VDC with a meter, especially for smoothness in increasing vdc when opening the TB by hand while you watch volts increase. Just want to rule in/out the VDC is within spec (there is a range +/- of .67 vdc when it is closed and if it is beyond that range it can throw a code

Bobby Dixon Jr

I know this is about a year old but i have the same issue with the 24x and a 58mm.
My tps is set at .67 and wot is about 4.5.
The graph shows a smooth flow (hptuners).
Not sure what else it is but i still need to do IAC adjustments.