Code P0121?
Race Director
Joined: Mar 2005
Posts: 11,549
Likes: 27
From: Southampton NJ
Originally Posted by schilitj
P0121 Throttle Position (TP) Sensor 1 Performance ECM--what does this mean?
Drifting
Joined: May 2005
Posts: 1,254
Likes: 0
From: Ft. Liquordale Florida
I was seeing alot of these on my initial tune. It also may indicate a MAF table issue (we had these on the 05's) where flowing over 450HP is more than the airflows in the MAF table was designed for. I don't know if there is a patch available for LS2Edit (there IS one for HP tuners, but you-know-who won't invest in BETTER tuning tools - **** me off sometimes they do). This went away when we started with the maggie base tune, as they DO patch the MAF tables. It's NOT the pedal switch or throttle body - it IS the fact that when you flow more than the MAF tables allow for, the ECU "thinks" the throttle body position is out of whack.
These issues did NOT exist in the 06 and newer ECU's as GM fixed the tables.
Tell "you know who" I told you this. I had a feeling you were going to see this issue sooner than later. The upper end of the RPM range can be "fattened up" enough to compensate for this issue. My major problems were in the transition to boost when the maggie bypass opened. These were also resolved by the MAF patch. With your procharger you don't transition, your boost comes in gradually.
Mod'ing can be a PAIN IN THE BUTT sometimes, eh?
Rick
These issues did NOT exist in the 06 and newer ECU's as GM fixed the tables.
Tell "you know who" I told you this. I had a feeling you were going to see this issue sooner than later. The upper end of the RPM range can be "fattened up" enough to compensate for this issue. My major problems were in the transition to boost when the maggie bypass opened. These were also resolved by the MAF patch. With your procharger you don't transition, your boost comes in gradually.
Mod'ing can be a PAIN IN THE BUTT sometimes, eh?
Rick
Last edited by SickRick; Sep 17, 2006 at 09:06 AM.
Thread Starter
Safety Car
Joined: Dec 2004
Posts: 4,477
Likes: 2
From: Boca Raton, FL
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14
Originally Posted by SickRick
I was seeing alot of these on my initial tune. It also may indicate a MAF table issue (we had these on the 05's) where flowing over 450HP is more than the airflows in the MAF table was designed for. I don't know if there is a patch available for LS2Edit (there IS one for HP tuners, but you-know-who won't invest in BETTER tuning tools - **** me off sometimes they do). This went away when we started with the maggie base tune, as they DO patch the MAF tables. It's NOT the pedal switch or throttle body - it IS the fact that when you flow more than the MAF tables allow for, the ECU "thinks" the throttle body position is out of whack.
These issues did NOT exist in the 06 and newer ECU's as GM fixed the tables.
Tell "you know who" I told you this. I had a feeling you were going to see this issue sooner than later. The upper end of the RPM range can be "fattened up" enough to compensate for this issue. My major problems were in the transition to boost when the maggie bypass opened. These were also resolved by the MAF patch. With your procharger you don't transition, your boost comes in gradually.
Mod'ing can be a PAIN IN THE BUTT sometimes, eh?
Rick
These issues did NOT exist in the 06 and newer ECU's as GM fixed the tables.
Tell "you know who" I told you this. I had a feeling you were going to see this issue sooner than later. The upper end of the RPM range can be "fattened up" enough to compensate for this issue. My major problems were in the transition to boost when the maggie bypass opened. These were also resolved by the MAF patch. With your procharger you don't transition, your boost comes in gradually.
Mod'ing can be a PAIN IN THE BUTT sometimes, eh?
Rick
FYI, both of the guys you reference should be getting the HP tune any day if they don't already have it. As you know I have an MAF issue were the rev limiter kicks in at 5022rpms, the HP tune will correct this. Just waiting for it to arrive.
Jeff
