Got my '02 running pretty well, but when I get it it hard (loaded or not) I get up to about 25 lbs boost and it falls to 18 to 20! Engine still pulls well but I can feel it fall as I watch the gauge. Any ideas? Already put in the 3200 spring and built a custom 4" turbo back exhaust outside of the frame, no air cleaner housing and I am a member of the pull cable club.

 

check the fuel filter I had the same problem and that solved it.

 

At what point is it doing this? Sounds like it is defueling. ARe you near 3200rpms when it does this? AT defuel, boost will come down.

 

It seems to happen near 3200 but it's not defueling from the govenor, I can run it right up to the govenor and it surges a little from 25..20..22..20 and then stays there. I'm wondering if maybe Murph is right, fuel filter? Maybe my tank is full of wOOter?

 

Ya I would bet on the fuel filter. My problem was the same boost would run up then it would kinda die off at full throttle.

 

O.K. I'll check it out. Now on to something completely different. I took out the radiator to replace the front seal, reinstalled it after cleaning the outside (it was quite nasty), installed a 16 lb. cap and replaced the hoses. Everyday, I fill the radiator and by the time I get to the shop, I'm a gallon low?!?!?!? It runs on the high side when low but doesn't go to 'H' (not even to the line before it). My fan clutch is now acting up, not sure why...300,000 miles maybe its time to give up the ghost? Maybe something simple, clogged radiator? Bad head gasket? It always seems to be bubbling coolant or air (not exhaust) into the over-flow tank and I never see any steam or water out of the tail pipe....any suggestions?

 

Tried the 'fan clutch immoblization move'. It turns full time now but still boiling out my coolant! Doesn't seem to be running quite as hot but I lost a gallon over a 30 minute period. Are these trucks supposed to have vented radiator caps? I think so, cause they wouldn't have a over-flow tank otherwise, right? May need to have the radiator rodded, I guess, see if that helps.

 

Somebody...anybody...