Gman77

Engine bucks like crazy even under light load so much the box has to be turned off. I was talking with TST a while ago and they were going to send some trouble shooting instruction for checking voltages.(The box was sent back to them and checked out serviceable) Does anyone have a copy of something like this. It the weekend so shop is closed and I would like to get a chance to look at it.

BLUTIC

There is two things that I have found that makes the engine shutter and buck. 1) The MAP sensor 2) bad pump connection

The TST PM3 brings on boost by the MAP reading, and sends fuel via the pump wire. Either could be the problem.

Gman77

The pump wire is soldered this was done after initially trying the Grabber. I was leaning to suspecting the MAP sensor, but don't want to replace it if is okay. Any test for the MAP sensor?

gandrews

I have read about some strange and annoying problems that were the result of a bad ground. Did you solder that also or use the grabber or ?


Good luck and post when you find out what the problem is / was.

George

Gman77

I soldered the ground also.

HOHN

could be a cold solder joint. Worst case, you can send the box back and have it tested.

Justin

Timinva

Is it a competition model? I had the same problems, ran fine at full throttle but any other throttle setting it bucked all over. I made a pigtail to plug into the map sensor and wiring harness to check the map sensor output voltage. After checking all settings my voltage was were it was supposed to be. I ended up with a custom program from tst. Rod at Wildcat worked with me and Greg at Tst to get it to work. Even with the custom programing it was very touchy with light throtle or the cruise control. Tim P.s. I will see if I can dig up what the voltages need to be at different boost levels if you need it.

Gman77

Box (not the Comp version) and harness was checked out by TST. I plan on checking MAP voltages tomorrow. Anyone have the voltage outputs of MAP for a '98?

Gman77

I have changed the MAP sensor. TST did not like the idle voltage of it (.73v). There is no change in the problem. Driving to work this morning, it was still dark, and under light throttle I could see the fueling light flickering off and on with the box on 8 and about 9ilbs of boost. When I got on the gas I had the old rodeo ride again. Box is turned off. Quite an expensive boost fooler TST has no suggestions for me.

j-fox

Is it electrical noise from the alternator?
Disconnect the output at the back of the alt. and go for a short drive.
Warning , I am not sure the alt will like this.
Does anyone know if the alt can be run with output open?
I will have to check the FSM , there may be a fuse you can remove.

Gman77

I'd be willing to try anything right now. Anyone know if this would harm anything?

fire1355rescue

hey Gman, does your truck throw a code? Mine does the same thing with the PM2. TST says my box is fine but for some reason my fuel cuts in and out at times. mine threw the dreaded PO216 code, cleared it, and it hasnt came back on since i took the chip offabout two weeks ago

BigBlue

Have you sent the box itself back to TST? Not just the harness.

Barry Smith

Gman, take the wire harness off the map sensor spray WD-40 put it back on. Mine has been doing this for about 4 Years now seems moisture has something to do with it. Spray plug with WD should take care of it.

fire1355rescue

TST said the box was fine...gonna put it back on and try it with the WD-40 trick