I posted this on DB, too, so sorry if you guys end up reading it twice...


My truck was running very well before I installed the governor spring and advanced the timing 12-14*. I got everything put back together and now I can't get the truck to make any power. The truck burns absolutely clean, no smoke whatsoever (which is kind of nice, minus the lack of power). I can only manage about 18-20lbs of boost at full throttle, in second gear only, every other gear is maxed at about 10 lbs. My EGTs are as cold as the ice age (floored up a hill I can MAYBE get it to hit 1,000*). Lift pump shows 15+psi at almost all times...

Truck is a 90, non-ic injectors, M&H M4 fuel pin, HE351VGT, 4" turbo back, custom IC, IC pipes, etc etc...

Now, after I got the pump back together, I backed out the full power screw for safety, put the idle screw back to where it should be, and the truck tried running away (surprised, since I backed the full power screw so far out). I backed the screw out more til it would not start, then turned it in a little at a time til it would start and idle. It idled high, so I backed out the idle screw (ended up backing it out all the way, which I understand is fine).

BUT, we had the issue that the truck would idle, but I would hit the throttle and the truck would die. Turns out we put the throttle lever/cam in the wrong position which was leaving some slack in the governor (yes, I forgot to mark where it was when I took it off... like an idiot). So, to remedy this, we found where the throttle would start to put a little tension on the governor spring and clocked the throttle cam to that position (so, we turned that splined shaft 90* CCW). Started the truck up, and she ran away. Backed the full power screw out and got her to idle well again, and we had throttle control.

Kept playing with the full power screw trying to get some power and it would either run away or die, all within less than 1/4 turn of the screw. We can't get ANY smoke out of it, even if she is running away (so probably not a true run away situation, but IDK what else to call it). The only way I could even get a hint of smoke is if I turned the smoke screw in all the way (so that the lock nut could not even thread on it). Starwheel is one turn from bottoming out.

The fuel pin does seem like it might be sticking, so I am going to look into this today a little more, but I still feel like I should be able to get SOMETHING out of the pump besides runaway and not running at all. The fuel metering pin does pop out when I move the throttle, so that seems fine.

I know this is a long post with a lot of information, but does anyone have any other ideas? Do I need to clock the throttle lever/cam more? I'm about out of ideas without taking it all apart and retracing my steps...

Thanks in advance gents!
MK

 

Keep playing with the throttle shaft. Sounds like that is your problem.

 

Its the throttle shaft indexing. Be careful. I was told you can't set the truck into run away by the indexing being off. But I did find it funny that I did it. Started the truck. Started to run off. Shut off okay twice before it was two far gone. third time it took off till it locked my ve and threw my camshaft gear off with the key turned off and i used the manual kill and it did nothing. Reason I tell you this is to be prepared. maybe it wasn't a true runaway. But it was enough to damage my stuff. By the time I had the intake unscrewed and was searching for a board it was too late. Preparation is the key. if I would have been ready I would have been 2 grand richer right now.

 

Yes, any time i mess with my pump i undo the intake clamp and have helper with me. The helper cranks the truck while i monitor everything.

 

Thank you guys! It was indeed the throttle lever indexing, I had it a bit too advanced so I wasn't getting the fuel I needed. And I was extremely cautious around the pump today, since I had no help. I backed out the full power screw and smoke screw til it would not start and adjusted it in small increments til it will start. It is nowhere near where I would like the tune, but it's safe and making enough power to move itself now.

Thanks for the help! Now just a few adjustments and I think I will be good.

In return for the help, I give you all some pictures!

 

Nice