i have a 94 with a 6.5 turbo the problem is lots of black smoke and not alot of power when you step on it.the college over hauled this thing 40000 miles ago and its suppose to have a new turbo and new injector pump bla bla bla.my thought is you should be able to here it whistle not like a duramax but still some whistle.any thoughts on this i would appretiate it.thanks

lots of smoke when you step on it? does the engine have the factory vac system for the turbo control? look on the turbo and if you see a black vac line running to the wastegate, follow it back to the driver's side valve cover. depending on if its an "S" or an "F" engine it may have either 3 solenoids("S" engines only) or one solenoid("F" engines only). the "S" engines have an EGR system which is what those other 2 solenoids are for.

look for a vac pump somewheres on the serpentine belt system. they tend to go bad and cause lack of vacuum, which in turn means nothing to hold the wastegate closed and create boost PSI. i had this issue with my truck and i replaced the vac pump and got my boost back. afterwards i installed whats called a Heath turbomaster, which is sold here (http://www.heathdiesel.com/P/HDP1243/), which takes the place of the faulty vac pump system. however if your truck is an "S" engine(check the 8th digit of your vin to find out) you'll need the vac pump for the EGR system or you'll get a CEL and an engine code.


also please fill out your signature which can be done here (http://www.dieselplace.com/forum/profile.php?do=editsignature). this is for us to assist you better as we'll know exactly what you've got and any and all mods done to it(if any).

thanks alot now that i think about it that vaccum pump was leaking air out the front of it ill check that out and i go from there thanks again

no problem. it should have air coming out the backside of the pump. its should be sucking air thru the tubes and blowing the air out the back of the pump(sorta dome shaped). if its doing that then it's working properly. the vac pumps are about $140 new when i bought one back in nov or dec 07. the heath turbomaster is $109 and you can make your own for about $10. if you get or build a turbomaster you must install a boost gauge first because if you overboost the engine you can and will break something, like blow out the headgaskets at the least. the max sustained boost with an intercooler is 15 psi. stock these trucks came with 21.5:1 compression ratio hence the low amount of boost as there not loads of room left in the cylinders. with the factory computer the max sustained boost you can cram in is 8-9 psi before the truck will throw a CEL and defuel( if the computer can't back off the boost via the vac system it'll cut the fuel which is turn cuts the boost back). my truck has a reflashed ECM so i have my turbomaster set to 12-13 psi and if i intercool the truck i'll bring in up to 15.

no problem. it should have air coming out the backside of the pump. its should be sucking air thru the tubes and blowing the air out the back of the pump(sorta dome shaped). if its doing that then it's working properly. the vac pumps are about $140 new when i bought one back in nov or dec 07. the heath turbomaster is $109 and you can make your own for about $10. if you get or build a turbomaster you must install a boost gauge first because if you overboost the engine you can and will break something, like blow out the headgaskets at the least. the max sustained boost with an intercooler is 15 psi. stock these trucks came with 21.5:1 compression ratio hence the low amount of boost as there not loads of room left in the cylinders. with the factory computer the max sustained boost you can cram in is 8-9 psi before the truck will throw a CEL and defuel( if the computer can't back off the boost via the vac system it'll cut the fuel which is turn cuts the boost back). my truck has a reflashed ECM so i have my turbomaster set to 12-13 psi and if i intercool the truck i'll bring in up to 15.

If you're needing a turbomaster, I just purchased one still in box and I don't think that's my problem as I have decent vacuum. I'd be willing to sell it at a little cheaper rate than you could get. It's through Heath diesel just like described above. I think my issue is the PMD or FSD. You can see my problem a couple posts lower called "Lotta Black Smoke". Sounds like we may have the same issue.

You can make your own Turbomaster, their is alot of people on here that have done it. If you post a new thread asking a bet alot of people would pipe in and share their wisdom on how to make it on your own.
A turbomaster is tons better than the worthless vac crap chevy used on the 6.5TD engine.