Hyundai Other Repair Question
TPS Performance Problem...DTC P0121
Here is a list of things I have tried since throwing this code. I have done the following:
1. ran multiple ground checks on all my wires
2. replaced the TPS with a brand new Hyundai OEM sensor
3. redid the splice connection for my TPS on my Mafterburner (fuel tuner)
4. replaced the ECU with a known good one.
5. cleaned MAF sensor - didn't do anything for me.
6. replaced MAF sensor with Hyundai OEM sensor.
The only two sensors that I can think of that would possibly cause this to happen would be either the ECT or IAT sensors, but I'm not even 100% sure of that.
So if you could please try and push me in the right direction, I would greatly appreciate it.
Thanks!
Asked by MacatronAnswer
You did the supercharge installation? And how many miles ago was that installed?
Yep, my roommate and I did the supercharger install ourselves. We're both gear heads, and we've installed many aftermarket parts on various vehicles. As for mileage...it was about 3,000 miles ago.
Thanks for replying!
During this issue you get no check engine light and that is still functioning, right? When you say no boost you mean the supercharger is not engaged? Is there a means to by pass or go back to prior supercharge and test the unit?
Well, the CEL doesn't initially come on. It takes a second drive cycle in order for it to throw. So, in other words, if I shut the vehicle off when it is acting up, and then start it again without pulling the ECU fuses it will throw the TPS performance code. But, being that I already know what code it's going to throw and how to temporarily fix it it (pulling the fuses), I don't bother letting it throw the code any more.
As for the supercharger not making any boost, I'm reffering to normal highway driving. The boost gauge is either reading zero psi or 10 to 20 inches of vacuum (due to it being a roots or eaten type of blower). I usually drive around 75-80mph on the highway in 6th gear turning about 3,500 RPMs.
Well, it would be a major undertaking to convert the vehicle back over the the factory manifold again, just to give it a try, so I'm hoping for another alternative at this moment and time.
I did notice that the Intake Air Temperature (IAT) was very oily when I reinstalled it during the blower installation, so I cleaned it with some brake cleaner. I didn't figure that this would be a problem, but I could be wrong.
So, with that said, do you think that the IAT is possibly the issue here? Or could it even be an Engine Coolant Temperature sensor (ECT)?
Thanks, and let me know if you need any further information.
What I am wondering is does the documentation for the supercharger make any recommendations of sensor updates or have a troubleshooting section. You have changed the air flow in the engine and somehow the engine does not seem to be able to handle in over the long haul and stumbles. You replace with OEM but isn't it possible that it needs to be replaced with other than OEM? Anyone else on the forum got a view or idea on this?