cquestad

A quick question...I am sure somebody remembers.

Will the truck run with the TST harness in place but the box removed? I don't feel like tripping any codes or unhooking more than I have to. I need to get some new programing!

I have a feeling that I need to remove the harness as well...just can't remeber what I did last time. Thanks!

Gypsyman

If I remember correctly from 2 weeks ago at TST you have to remove the timing harness but the injection harness is ok to leave in place.

Richard

cquestad

Thanks Gypsyman...should I get the Twins or Aggressive Program? That is the next question. I will most likely have twins in the near future...

Tom488

Correct (although I would think the MAP sensor would have to be restored to stock connections - only the injectors can remain hooked up) - the crank/cam sensors need to be re-connected. I inquired last year about the possibility of loopback plugs to connect to the harness, and allow them to remain in place. TST said they had thought about it, but nothing ever developed.

Doesn't it figure? The easiest connectors can remain in place, but the most difficult ones need to be re-connected

cquestad

Thanks all.

cquestad

Well...I think you have to remove the MAP plug too...I just did the timing harness only and started it...ran fine but had CEL. Anyone else remember...even though it is too late for me.

Tom488

You would have to - since the TST does boost fooling, it has to limit the voltage being fed from the MAP sensor to the ECM. It can't do this without actively intercepting the signal from the MAP sensor, and spoofing it's own signal to the ECM. If you don't restore the stock MAP sensor connection, you've effectively disconnected the MAP sensor, and that's why your CEL is on. It's an easy enough connection - just restore the stock connection, and the CEL should disappear shortly.

cquestad

Thanks...makes sense...truck drives fine without for some reason???

Fred Swanson

Does the engine roar like the fan clutch is locked in? I seem to recall having a map sensor connection not making a good connection and the fan never released.

Tom488

It may seem like it, but it really isn't. You have no injection advance, because the ECM doesn't know how much boost is being made. So, you're down on power, and you're not as fuel-efficient. Plug the stock connector back in.

cquestad

Well..I am down 200hp anyways with the TST off...I couldn't tell anyways! I will go unhook now.

Thanks guys!