TST P-max stumble/hesitation

[JB @ C and L Machine]

I have the P-max 3 on my 99 Ram and it seems to have developed a stumble or hesitation. I had a problem about 6 months ago with it not fueling till 15 psi. I changed the boost fooler and it worked. Now it stumbles and hesitates. With the box off the truck runs fine. I was gonna start over and re-check the connections and add some di-electric grease. Any other than that I guess the box will need to be checked out. JB

 

[78repowerwagon]

If I remember right, TST has changed the location of the ground from the air intake to one of the wires in the truck harness. I can't remember which wire. Anybody here know?

 

[Idaho CTD]

It is the Black/tan wire that is the pump ground. You can find the updated installation instructions on their website www.tstproducts.com. I did mine about a month or so and it stop the stumble/hesitation but now my truck surges going downhill. I'm wondering if it is a TPS sensor. Any ideas or has someone else had this happen?



Nathan

 

[tobaccogrower]

check engine light

have eny of you had the check engine light come on?

it's happned a few times with the tst on. its set the code and put the truck in limp mode! i've taken it to the dealer and they say the code is from the tst not communicating with the map sensor. i called tst and they say thats highly unlikely. it's getting expensive to have the stealer hook up my rig to the computer. any ideas/solutions? TIA... james

 

[Steve St.Laurent]

There was a problem with the early TST wiring harnesses with the MAP sensor connection. I had one of the first powermaxes (9/99) and had a MAP sensor harness that had the problem and TST replaced it with a later harness that solved the problem. It would turn on the check engine light when it happened. They only had to replace the map sensor part of the harness - not the entire thing. On my truck you could tell the intermittent connection by turning on the key (without starting the engine) and then wiggling the MAP sensor harness around and you could hear a click in the injection pump. I also had trouble with the scotch lock connection at the injection pump after it had been on the truck for a long time (70,000 miles or so). I ended up just soldering the connection to the injection pump since I wouldn't have tried to get warranty on my VP44 anyways.