A while back I posted about loss of power. A new cat and new fuel pump, both of which helped some, have not solved my problem. Boost is about 10 pounds max. The intake has been pressurised from the turbo on and no leaks found. AFC and wastegate actuator diaphrams appear to hold pressure. Pre filter cleaned (nothing to clean out really) and fuel filter changed. I can find no play in the turbo shaft, it spins freely, and whistles quite nicely when running w/o cat or muffler. Someone suggested the AFC may be the problem. Has anyone any suggestions as to how to check it out? My service manual is silent on the matter.

Thanks for any suggestions or direction.


DRam

 

what air filter are your running???? sounds like a collapsed/ really dirty air filter.... take your intake tube off and power brake it.... you should be able to build 10-15 lbs no problem just powerbraking. if you all of a sudden start building boost without your air cleaner on there, then you found your problem. alot of the guys in my area have been having problems keeping air filters on thier trucks, i know 5 guys within the last 3 weeks that have collapsed air cleaners on their trucks.

 

Excellent suggestion. The filter looks good, but I'll try your idea. Thanks.

 

Tried it. Managed 8 or 9 pounds of boost, but didn't try real hard. My clutch is iffy, and I don't want to abuse it too much. I'll take it out for a short drive after lunch and try it on the road.

 

don't drive without the filter for long though, u don't want anything getting sucked in the turbo... Have u checked ur gov arm posisiton where it hits the plate?

 

What kind of shape is your exhaust in? I have had a muffler come apart and block the exhaust. You could probably hear a restriction if you had someone hold the throttle down.

 

he already took care of that

 

if everything else checked out good i would guess the afc diaphram in the housing.

 

No effect w/o air filter. I'm guessing the AFC also. The governor arm & AFC diaphram: how does one check those out?

 

pull the afc housing off and the aneroid diaphram is inside. while you have the housing off you can check the governor arm but not sure if thats whats causing your problem. will the truck get up to speed but just slow at it?

 

my truck had the same problem, 10 lbs boost tops, no power, i checked all that other stuff. it ended up bein my shutoff solenoid shaft wasn't pulling up all the way. check your shutoff solenoid shaft and see if it's out of adjustment. i think it's supposed to be just over 2 and 5/8 inches i think, but that might be off so ya might wanna look it up i don't remember specifically. another thing ya might wanna check is your overflow valve, i've heard people having same symptoms but that was the problem. just a few things to check hope it helps

 

First, thanks to everyone that gave me suggestions. I'll write them down in case these symptoms ever arise again.

Second, the winner, the man with the right answer, is . . . clutch1. He suggested the AFC, and that's what it was. Tonight I got brave and took it off. The diaphram holds 30 pounds of air indefinetly, it moves as it should, however there is a slotted limit plate (? right term?) fastened to the housing, that was cocked and apparently jamming things up. I straightened it, moved it all the way forward, and put the AFC on, moving it all the way forward also. Ahhhhh, the feeling of success. The feeling of power!

Thanks again everyone. Your time and suggestions are greatly appreciated.

DRam

 

wooohooo... glad you got everything running good.