LQ4 tune help
Thread Starter
Teching In
Joined: Feb 2022
Posts: 5
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LQ4 tune help I had my LQ4 tuned a couple times at a local dyno after I swapped it into my 74 Camaro a few years ago and the tune ran great. Over the last year I keep getting a p0121 code for the tps even though it is working properly and the same for the map. I went through all the diagnostic steps and everything seems to be working. When the pcm shoots that code the engine starts to die while in gear and have to rev it to keep it alive. When in park the engine revs high and has no apparent problems. I just purchased hptuner and a wideband setup to try to tackle the issue itself if it is a tune problem.
Ill attach the tune file and a basic log if anyone can look at it. Ill list the modifications below:
2002 LQ4
LS6 Intake
SUM-8701 Cam
1W7E-A5A injectors
Longtube headers
80mm tb (dbc conversion)
Th350 trans
2500 stall
255 lph fuel pump
58 psi pressure regulator
No O2s currently but will have later
Ill attach the tune file and a basic log if anyone can look at it. Ill list the modifications below:
2002 LQ4
LS6 Intake
SUM-8701 Cam
1W7E-A5A injectors
Longtube headers
80mm tb (dbc conversion)
Th350 trans
2500 stall
255 lph fuel pump
58 psi pressure regulator
No O2s currently but will have later
I had this problem with a cammed LS1:
https://forum.hptuners.com/showthrea...the-P0121-Code
I bet this fixes it for you
https://forum.hptuners.com/showthrea...the-P0121-Code
I bet this fixes it for you
Thread Starter
Teching In
Joined: Feb 2022
Posts: 5
Likes: 0
The tune already has that min/max set to 0 and 100. Thanks for the article though.
Ive read through pretty much every p0121 code article there is and nothing has solved the problem. The map sensor can also set off this same code if it is not working properly. Ive bench test the map, checked wiring, and checked for vacuum leaks and cant find a problem. The only thing I can see is that the map sits around 105 kpa and only changes under sudden deceleration. I'm not familiar enough with the values or the scanner yet to be able to say what is going on.
This issue has been killing me.
Ive read through pretty much every p0121 code article there is and nothing has solved the problem. The map sensor can also set off this same code if it is not working properly. Ive bench test the map, checked wiring, and checked for vacuum leaks and cant find a problem. The only thing I can see is that the map sits around 105 kpa and only changes under sudden deceleration. I'm not familiar enough with the values or the scanner yet to be able to say what is going on.
This issue has been killing me.
Might be a long shot, but I had this same issue and it actually ended up being my battery....... during cranking the voltage was dropping to low causing the ECM to do some funky stuff reading the TPS and IAC.
Just a thought, could be a bad connection or bad ground?
Does it do it randomly while driving or directly after startup?
Just a thought, could be a bad connection or bad ground?
Does it do it randomly while driving or directly after startup?
