danbaldy

Just installed tst pm3. now I have a bad shudder or bucking on levels 7-9 during normal driving. Has anyone else experienced this. Wonder if I made bad choice for box.

Monty

Have you checked your fuel psi lately?

scottrod

Is your trans stock except for a shift kit?

danbaldy

Fuel pressure is 13psi at idle, don't know what it is driving down the road. I've ordered a dipricol fuel pressure gauge but it's been back ordered for a month now. The trans is stock except for the shift kit. Have new tc. setting at the shop to be installed next week. It feels more like a fueling problem than a trans problem. Can't put my finger on it.

scottrod

I would check fuel pressure at WOT also.<br>Mine would go to 1psi with the same setup that you have except I was on level 4. I changed Banjo bolts and now it won't go below 5 at WOT.

Battering Ram

If the shuddering is small and occurs after you take your foot off the go pedal this is normal... The TST PM3 is very aggresive and the VP44 actually shudders during defueling. If it is happening any other time there is probably something wrong.

777 MECHANIC

I had mine upgraded to the comp. version. I didnt have the shudder before the upgrade. With the upgrade though it shudders violently in 7-9 when lifting off the pedal slowly after a hard acceleration.<br>MikeD

danbaldy

I usually don't drive on that power level, but I drive interstate to and from work. And I was just playing with the box and noticed that on those power settings the truck does this. Just trying to keep a steady speed,70 mph. Don't know if I have a problem with the truck or the box, or if this is normal.

CMN_NOT_STROKN

Mine will do it and I only have a PM2 which would be on level 6 on your box. I think that my lift pump is going south. I need to hook up my fuel guage but it has been snowing and cold lately and haven't gotten around to it. I have just been driving around for the most part with the box OFF!

Push Rod

With a TST PM3 Competition box, this shudder is normal as the box is very aggressive getting on (and off) the fuel. However, a standard PM3 (or 2 or 1) should not exhibit the shudder problem unless you're having some fueling problems. As Scott said, I'd have a look at your pressures at WOT. I've seen a couple lift pumps that read 13 - 14 PSI at idle, but at WOT, the pressure would drop to 1 or 2.<br><br>Until you get your pressures checked out, I'd stay away from the power levels that are shuddering on you (unless you've got the Competition module).<br><br>Rod

danbaldy

Yes I do have the competition module. Since I have not received my fuel pressure gauge yet I will hook a pressure test gauge and drive the truck and see what readings I get. I will do this tomorrow and let you know. I really appreciate all of your help with this. I will keep you posted. Thanks Dan

PourinDiesel

Dan,
I dont believe the shuddering/bucking of the fuel pump is a fuel pressure issue.
It lies in the aggressive programming of your Competition Power Max 3.

Edge had a problem a while back with this on their Edge Comp (level 1, I think it was).

You might have Mark Chapple adjust or reprogram your box if you do not wish for this to go on.

If your pump/PM3 is turns out not to be the source of your issues, it could be your overdrives in your transmission slipping while underload.

--Justin

BigBlue

If I ran my comp on 3x3 then put it on 1x3, it would shudder like a mother. If I put it on 2x3 or turned it off, it would quit. I'm sending it back to Edge to have that and another problem fixed.

Pa outlaw

you may want to talk to doug at adt about this problem,i was going to install one of these on my truck and was told that they are great boxs,the only down fall to these boxs were they pulse the injectors to keep the cylinder lubricated in which they make a shuder,they say it happens more on a automatic and not really noticible on a stick shift,hope this helps you out,mark chaple is a good guy dont be affraid to call him up and ask him what he thinks,good luck

Push Rod

[quote author=Pa outlaw link=board=7;threadid=11330;start=0#109286 date=1046266432]<br>the only down fall to these boxs were they pulse the injectors to keep the cylinder lubricated in which they make a shuder,[/quote]<br><br>I'm not sure what Doug is getting at with this description, but all fueling boxes pulse the injectors. When the ECM tells the VP44 to inject fuel, the pump sends enough fuel to the injector to cause it to pop-off. The pump will then keep feeding fuel until the ECM tells it stop. This is an injector pulse.<br><br>The shudder in the Competition box comes from winding the pump out hard (which the box does on the higher settings), then getting immediately off the throttle. The TST Comp then aggressively defuels, shuts the pump down hard, and your shudder occurs.<br><br>Rod