Ok, 9 months ago I had a random low power issue and now out of the blue it is back! The symptoms: The pickup excelerates, but very slow........at wide open throttle (WOT) the pickup will only produce a max of 2psi of boost and a EGT of 700*. With these conditions, the pickup acts like it's not getting enough fuel. The fuel filter was changed just 1.5 months ago and everything has ran beautiful until this afternoon. Last time this happened, I had a local diesel enthusiast come by my house and help take apart the top of the pump and inspect things inside: Nothing was out of place, broken, or any reason to cause concern. We put the top of the pump and AFC housing back together, the pickup gained all of it's power back mysteriously! ????? 9 months have gone by with flawless performance and now the problem returned this afternoon. Anyone have a clue as to why this problem is occuring? The physical thottle cable and pedel works (pedal to floor does make the pump go to WOT) and I checked the inner-cooler boots to make sure one isn't leaking or has blown off. Everthing under the hood looks intact. I'm really stumped folks! I messed around with this problem last time and never found the root cause..........I really hate to waste weeks and months going over the same stuff again. I just need some 1st genner input and see if this might be something common to other people. Thanks in advance.

 

Fuel pin sticking, not riding out against the fuel cone - the one we shave or grind down. Remove the afc cover housing and inspect and or lube.

 

also i had a truck that smoke bad, and felt like it was running out of fuel and we took eveyrthing apart and could figuar it out. turned out they fuel suplie line from filter to ip was twisted and not letting enough fuel through aldo it could be the return springs are broke , my truck kind of did the same thing but it still ran fine

 

Ok, found out is was a mechanical issue: The high idle screw had vibrated outward making the stop stick out 3/4". I re-adjusted the screw and problem solved!!!

I love fixes that don't require a dime, just some basic inspecting

 

Need to back it the rest of the way out into the trash can. We don't need no stinking high idle screws!

 

I'll second that!!!

 

This poses a question for me: In order to "enjoy" the benefits of a 3200 gsk (366) spring..........does a person need to eliminate or adjust the high idle screw most of the way back to have that added rpm? I'm sure this is a dumb question..........but wanted to just make sure.

 

I don't even have one, but I will watch the tach if this thing ever moves again.

 

No, it will still wind up higher than stock even if you leave the high idle alone. And the big benefit of the 3200 RPM spring is the throttle response, you will get that no matter what you do. You will get even more throttle travel and RPM if you mess with the high idle - and since you have to remove it to get the pump top off, why put it back to stock?

 

Another mod to consider, to aid in future pump top removals and low idle adjustments. When you have the pump top off, completely remove the low idle screw if you haven't done so already. Flip it around, then thread it in from the front side of the pump. Then put a nut and lock washer on it from the front side. This way you can adjust the idle from the front, the slot in the screw will face the radiator.

BUT that's elementary, what I found next to do is, the rear section of low idle screw that sticks back and can be in the way of the hard to get to allen screw (back rear corner). CUT that SOB in half!! Take a cut off wheel and cut the extra off so it won't be in the way again! You'll still have plenty of threads for low idle adjustments too.