When the pedal is pushed down about 10-15% of it full travel limit, the afr is dropping down to the low 16s- 17s. When I let up just a bit, to like 5% or if i give it more gas, say 25% pressed, it comes back to the normal 14-15. The car has always run 14-15 afr at just about every throttle position, except for 75% - WOT. You can tell its going lean because it jerks a little bit. Not noticeable to a passenger, but i notice it. The idle is fine and the decelerating to a stop is fine. No other issues other than that one spot on the throttle. I have a feeling its the TPS, throttle position sensor. Anyone ever heard of or have had this problem?

All my vac lines are fine and dont have any other issues. This just started happening out of no where and Im not throwing any codes.

 

Boosted with a piggy back? If so that is your problem piggy backs can only control 100% of throttle at WOT.

 

I assume this happens off boost right? but anyweiz thats fine while in vacuum but some tuning can help that though depending on your engine management.. leaning part throttling while on boost is what you should worry more

 

Im fully aware of that. Thanks..... But the unichip is not the problem.

Your statement completely contradicts itself.....

 

No this doesnt happen under boost. If it was running that lean under boost I would be very worried. And I still dont think it has anything to do with tuning.

 

Read the statement it doesn't contradict itself! Piggy backs cannot tune partial throttle the OEM ecu still over rides any setting during part throttle. Piggy backs will only have 100% control over the engine at WOT!

 

Your not telling me anything i dont already know.

Having a piggy back is not a problem. Id say 90% of boosted tCs are running off a piggy back as well as most cars with aftermarket turbo systems. So i dont understand what your saying..... Your saying if you dont have standalone system, then you have a problem.......

You wrote:
Having a piggy back is a problem?

 

Really 90% of people on here are running piggybacks I never new that! Thank you for pointing out the obvious.

When you are at partial throttle the computer relies on input from various sensors and adjust accordingly, with a piggy back you are modifying this signal and the computer will still adjust itself from the modified signal.

At wide open throttle the computer doesn’t use feedback from the 02 sensor, instead it relies on the computer program and this is why the piggyback has full control over WOT.

 

Dude.... just stop. I didnt want an explanation of basic EMS operation.
Your first statement doesnt make sense. Whatever..... Just drop it.
And stop trying to inform on stuff i already know.

Has anyone ever experienced problems with the TPS?

 

not sure if its your tps but could be but other possible cause could be dirty maf or throttle or try resetting the ecu and see its your fuel trims.

 

I never said the piggyback was the problem, I said the piggyback would not fix the problem since the OEM ECU will keep adjusting.

 

not actually sure how the unichip works but some user says it does tune partial throttle so does the aem FIC.. from what i've read, aem fic has an O2 spoofer that alters the voltage from the O2 sensor thus it cant correct the afr like before

 

I had an inkling it might be a dirty MAF..... searched around this morning, found some cleaner, cleaned it up.... and it appears to be better. The only thing is... this problem was intermittent from the begining. So I dont know if it actually fixed it or not. I guess ill notice it over the next few days. Ill keep you posted.

The FIC does tune to partial throttle, but I know the unichip doesnt. The unichip isnt a great ems for FI cars. There good for basic mods, I/H/E...... Turbonetics kind of cheezed out there by using it in there kits. I plan to eventually go complete standalone, but thats not priority on my list of things to do.

 

^ I agree