The Optic bump repost was getting a bit long so I figured I'd start a new thread with my request. Just wondering if anyone has handy what the optimum specs are that we should be looking for with a MT2500 when doing the bump and pump adjustments.

if you start with a stock time of 3.5* btdc and move the optical 1mm, timing could increase as much as 1-2*'s, iirc 1mm=2 degs on the pump.

Ok, I have done that but what I mean is, if I have a fuel rate of around 3.6 and a btdc of around 4.7.....is this ok, or am I out here. I have a funny feeling that my pump needs to be advanced a bit. As soon as I was able to get -5.7 for timing my fuel rate was in the toilet(1.6mm)!:eek: I am just wondering why this would be? I am under the impression that the fuel rate should be around 4mm at 600rpm warm, right? Keep in mind that these are readings with an MT2500. I am kinda lost as to what I need to do.

4-5mm L.I. engine full warm is about as low as you can make everything still function normally. Stock is usually in the 8-10mm range, so this is a gain of roughly 4-5mm fuel across the board and about 1½-2 deg. advance timing on your fuel delivery.

TDC Offset should be the same as you would look for in a 'non-bumped' truck. -1.5 to -1.9 area or slightly higher up to -.25 will work. Keep in mind, everytime you move the optic sensor, it has the effect of moving the pump housing the opposite direction.

So, on the MT2500 the TDC offset would read -1.5 to -1.9? Or is that on a Tec2? I only have access to a MT2500 so I just want to be clear. Thanks alot for all your help by the way!

TDC Offset will show the same on either one. Apparently the difference is inside the Time Set Function, but I'm not 100% what, if any, the difference is.

Ok, I'm not sure what happened, I must have recorded the wrong TDCO the first time. I now have -5.7 and a fuel rate of 4.7-4.9mm engine warm @600rpm and the truck runs very good. Took a drive with the trailer on and it runs great, egt is good and power is up. Oh, and I discovered that my Turbo Master linkage was binding a little due to the angle of the compressor housing for the intercooler, so did a little rounding of the edges on the linkage and added a little neverseize for good measure and works like a dream now. No more overboost for me! Big thanks to TDG and QM for all the help!:)