po121 tps code

[rletzgus]

I am getting a p0121 code, tps range or performance circuit a. it happens everyday. I tried a tps relearn. I got new ac delco tps. adjusted parameters on tps v. mph on U7198. I have 80mm BBk TB on my truck. When this code comes on the truck will not upshift or even let the torque convertor turn off. it will bog in 3rd. The code usually happens at cruise. sometimes the shift parameters are different. Quick sometimes and slow others. Do I need a custom tune? I did the tps v. mph parameters botth ways up and down and it still throws code. any advice?

[CANUCKPREDATOR]

Have you tried with the stock tune installed to see if the code still shows? Delete code with Predator, reinstall stock tune and test if it still shows. If it does, there is something up with the truck that needs to be looked into.

[mikel]

Hmmmm...try a Google search on BBK Tbodies on 05+ Mustangs....sounds like a familiar issue to me.

[rletzgus]

Yes I have tried the stock tune and it didn't show. Also with the stock TB it didn't show.

[rletzgus]

I found no connection on Google about BBk and tps codes connected. Also, reading how the MAP and tps are "connected" for this code. will check the MAP sensor too. But I doubt this is to work.

[mikel]

http://www.allfordmustangs.com/forums/5 ... blems.html

http://forums.mightymustangs.net/index. ... opic=12823

http://www.americanmuscle.com/bbk-trouble-shoot.html

Just googled BBK throttle body issues...

Again, most of these are Ford related issues, but you get my drift.
I would suggest you post up on maybe LS1tech and see if anyone there has experience with the BBK Tbodies.

[rletzgus]

Thanks so much for the info. I will check the TB too. It just aoccured to me. Earlier when I installed it a year ago it would idle funny with surging and when it was cold it would be high. Now it's better. I wonder if it needed to be "broke in" and the edges worn? I adjusted the idle screw per instructions. maybe the tps is going below or above voltage because of the idle screw adjustment when i take my foot off accelerator? Arrgh!!

[rletzgus]

NO this did not work the tps is fine the voltage is straight and narrow good. no shorts. I believe this is a programming error. What can be done?

[mikel]

How long was the tune in the truck before you started getting this code?

[supercatxr7]

Do a search on LS1Tech board for this code. It can be corrected with adjustment to min/max map settings according to posts on LS1tech.

[rletzgus]

The tune has been in the whole time I'm getting this code. The code appears everyday. Today it showed and when it did the truck won't even upshift or anything when I step on accelerator. It seems to vary in appearance from day to day. Sometimes it's more and sometimes less.

I'm gonna put the stock tune in on way home from work one more time to see what happens.

Supercatxr7, I don't have the MAP options.

[supercatxr7]

Yes, I know, neither do I! I don't think Diablo is able to change this through custom tune either. I had same code after putting on a ported throttle body, Diablo could not change the min/max map settings. So I'm not using the ported throttle body.

[rletzgus]

That sucks, no way to tune it out? What a waste of 300 bucks (for 80mm TB). Contrary to popular belief I do think it helps to have 80MM TB. MY truck will pull my trailer at top of pedal now.

OK Also looked in LS1tech.com and p0121 is coming on because the MAP ranges are not wide enough for aftermarket cams that are big. I don't have cam but have FIPK and 80mm TB. Also had trouble with quick shifting which is MAP sensitive too I believe. Larger TB is wil cause a lower MAP pressure? I will look at MAP readings on way home. Predator is in PSI reading though and the parameters are kPa. Will have to convert to see. I hate to go back to stock. Defeating the purpose of trying to make cars more efficient.

[rletzgus]

OK Also looked in LS1tech.com and p0121 is coming on because the MAP ranges are not wide enough for aftermarket cams that are big. I don't have cam but have FIPK and 80mm TB. Also had trouble with quick shifting which is MAP sensitive too I believe. Larger TB is wil cause a lower MAP pressure? I will look at MAP readings on way home. Predator is in PSI reading though and the parameters are kPa. Will have to convert to see. I hate to go back to stock. Defeating the purpose of trying to make cars more efficient.

Here is a link for code p0121 reasons in LS1 based engines. http://www.ls1tech.com/forums/showthrea ... ight=p0121

Is there anyway to program using a custom tune or the predator to set the MAP parameters to 0 to 100 kPa? The stock settings for the Diagnostic Trouble Code being set is 55-65 kPa for 20 Seconds. The MIL will illuminate if these conditions are met for 2 ignition cycles. I did some conversions on my MAP settings and they are 5.4 PSI or 37kPa to 14.4 PSI or 100kPa. These parameters are easily over the limits to set the DTC and MIL. ????