When I turn my PM3 up to the higher levels everything seems to work correctly, but in a low boost and fuel situation at cruise speed, the engine seems to have a slight shutter, or surge. It is more noticable the higher the level. Any ideas? All the connection indicator lights on the TST are showing that everything is normal.

 

Thats normal for a TST Comp and higher levels on the PM3, crusing.

--Justin

 

Thanks Justin. I was worried about my vp44. My fuel pressure is dropping to near zero at WOT and my egt. will surpass 1400, so I am not finished yet. Thanks for the reply.

 

Mine did it to. Fine at wot but at part throttle it would surge above setting 4. Be carefull with your fuel press that low. The wildcat max flow fuel kit would work well in truck. Tim

 

That's perfectly normal. The TST add's so much fuel, it surges the VP pump. I'd definately would look into a different fuel system. Maybe a FASS, holley pusher pump setup, or a PE pump.

 

Whats your boost level at when this is occuring? The TST (and the Edge Comp) each start to add fuel at a given boost level, so if you're driving at about that boost level, you'll get some surging. Earlier versions of the Edge Comp (v4.0 and under) exhibited a pretty good surge at about 4-6 PSI, due to it being a heavier fueling box back in those days. The TST is still a heavier fueling box down low, so what you're feeling is the box bringing fuel on, then off, then on, and etc etc etc. The box is simply trying to figure out what you want it to do. To get out of the surge, simply let boost drop a lb or so, or let boost come up a lb or so.

If you're running the TST Competition box, you'll get a pump shudder in levels 5 - 9 when you are under full throttle or when backing off the throttle. This is due to the very aggressive fueling of the TST at these power levels.

Rod

 

I will say from experience, that I do not have much shudder now with the same PM3, same VP44 that was shuddering on level 4 before the cracked block, and with an EZ stacked onto it. The VP44 had seen several 1/4 mile runs before I noticed I had 0 psi fuel pressure while going down the track. I figured it was on its last leg and got another pump (also warranty issue involved).

After being "stock" for a while and getting the cracked block repaired, I put the original VP44, and PM3 Comp back on. I have noticed no shudder at all with the FASS on it, on level 5. I am amazed, since I thought the VP44 was on its way out. I have run it for a little while on level 6, but have not put my Scotty II back on yet so I am not doing much over level 5 right now (this can do 1400 EGTs with the stock airbox).

Chris

 

Thanks for the info guys. I think mine is worse than you realize. I can even feel it on level 2. It is bad enough that I turn the box off when I want to cruise. It isn't at any certain boost level. It is like the only time it doesn't surge is when the box is adding fuel. Like the only time the box is happy is when it is pouring fuel. As I said earlier, the indicator lights on the box say everything is ok. I wonder if the Grabber has a good connection?

Also, will a maxflow kit from Wildcat be sufficient for my setup? Should I stack my Diablo with this TST PM3? I thought about it just to see if the shutter would go away.

 

The maxflow kit definately would not hurt your setup. If anything, I'd say it might help it.

 

Here is what I figured out. I checked all connections including the pump wire. I wire tied everything down, so there would be no adverse effects to vibration. I took it for a spin, and guess what. The shuttering is still there. But I found something when I pulled back in the shop. In neutral with the PM on levels 1-9 the truck idles perfect, but when I run up the rpms to about 2300 and boost comes up to about 5(give or take) I notice the fuel light on the box starts to pulse dimmly and gradually come on solid (still dim) with more throttle. My conclusion-- whatever the box is looking at to bring on fuel, is pulsing, or the box needs a newer software version. Mind you, once I get past that transfer from fuel off to fuel on, the truck is smooth as ever, but you can't drive through this problem. I have tried. Is the map sensor giong bad? What is my problem? How much is a new map sensor.

 

My PM 2 does that when it gets moisture in it. I cleaned all connections put dielectric grease on everything and shrink tubing and the problem went away? I hope that helps?
Barry

 

I say send the box back to TST and let the reprogram it with the latest software. Not only could it possibly solve your problem, but you'll also be getting the utmost power from your rig.

 

Ditto on Wildcat max fuel flow system!

I put max fuel flow on before I switched from EZ to PM3. Have never had any surges at any power setting and can't pull FP below 8.
Rowland

 

Barry,

How is your box getting moisture in it? I have mine mounted next to my trailer brake controller and my remote just below my sterio. I will check all connections again, but I don't think that is it.

 

hey blutic,,,i stacked a diablo puck with my powermax comp and all fuel shudder completely went away.the power really comes on fast now,,and you get alot of smoke until boost comes on,,then it clears up nicely.....as mentioned before if your fuel light is flickering at about 5 lbs,,that may be the boost level that the box is starting to add fuel at and causing the feeling your getting.if i were you i would call mark at tst and ask him about it,but he wont give any input on stacking ,cause he doesnt condone doing it........bama