jg7103

Hello all.... im new to the site but i have a huge problem..... i have a 99 cummins 2500 5.9 I6 turbo.. i just installed a magnaflow turbo back exhaust, K&N intake and hyper tec hper pac comp. it now tells me im over boostin and p0122, baiscally when i put it in drive and it engages i go to press the throtle and it wont pick up, REALLY slow untill i get up in to high rpms and its fine. its really only 1-2 gears. i just tried doing a APPS reset and it helped a little but did not fix it 100%. and after the reset the hyperpac detects no bad codes.....

what are my options with fixing it?!?!

Tate

Does it go away if you put it back to stock? Did you put a boost elbow on at all? If the computer detects over-boost, it will defuel the engine and be pretty wussy to drive.

The P0122 code is TPS voltage low. So your APPS may be the culprit, which would explain the lack luster performance. Did you do the reset, and then check the codes, or did you go for a drive, then check? It may take a while for the code to show up. Sometimes I'll get a P0238, clear it, and won't get it again for a long time.

Although I'm sure you've heard this before, get some gauges on your truck soon. Not only do they look pretty, but are good for keeping an eye on everything, as well as trouble shooting issues like this.

jg7103

well i did the reset and it wasnt AS bad even in stock or the other level. i didnt do anything to the turbo just intake exhaust and hyperpac. now im new to diesels so what does defueling really me? just stopped adding fuel? but its fine when im up to speed...when you say its culprit what does that mean? thanks!

Tate

Defuelling is when it cuts back the fuel. If the ECM sees an overboost condition, it will reduce the amount of fuel to bring the boost back to 'safe' levels.

If the APPS isn't giving a full voltage signal to the ECM, it won't let it fuel as hard. So thats where I'd start looking. If you've got a friend with a truck with a good APPS, try swapping them and see if it helps. They aren't cheap, and throwing parts at it won't neccesarily fix the problem.

msgtdave

I have a simular problem and mine is strickly stock. I just wasted over $180 at the Dodge dealer. Checked out a lot of things, but fixed nothing. Mine has slow acceleration or no acceleration at times. This may occur at take off or while I am riding down the hwy. Then all of a sudden, it will work like it should. I have a spare lift pump that I am going to install and see if it helps. Would appreciate any other ideas. Really enjoy this web site.

crobtex

I really hate to sound like a broken record, but.....you really need to get gages on that puppy. Especially pulling that 5'ver.

I don't think you can do a lot of trouble shooting until you check the fuel pressure. If you have good pressure and still have the problem, your injector pump is probably going bad. In my case, and from what I have read, the APPS will cause a momentary loss of power. I never had a "low" power problem, just short spurts of dead pedal.

reddawg

i had the same problem slow to accelerate but then when rpm came up would run fine i was just about to scrape my tst prw max3 until i called them the guy i talked to there said to pull out map sensor clean with brake clean and reinstall i did just that and the problem went away. he said what happens is the motor will suck in the oil from my k & n filter and plug up the sensor of which would send false signal to injection pump causing it to defuel give that a try it worked for me hope this helps