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6.5 turbo(gm4) on a 6.2

I figured I'd better update every on the progress. I happen to have a good day at the wreckers and found a IP. still has over 200K miles on it but it starts now. the only thing I ran into was a pile of smoke(it hasn't been started for a couple of months) and the idle took off. I'm wondering if the PO turned the pump up some before? it came out of a van it that makes any difference.
 
I've got the idle straightened out(turn the screw back some) now I just have a rough idle, and a ton of blue smoke. I mean hide a house cloud of blue smoke. what am I missing this time?
 
Sounds to me like your IP is shot. My blazer idled like crap(very lope-y and lots of stumbling) and smoked blue like a SOB when the IP was shot. Seen many DB2s that did this when dying/dead.
 
well time for an update. Man it's been a long year. I got the truck up and running for the most part but ran into a SNAFU. Instead of the turbo producing pressure it creates vacuum.

Somebody wanna tell me how this is even possible?????

I don't have the numbers on how much vacuum.
 
I came up with one possibility. what if the turbines aren't goings fast enough? they'd end up as a restiction then. The bearing feel tight, so I'm wondering if it could just be sludge build up or lack of fresh oil. if so what's the best way to clean it out?
 
that's what I was thinking. this turbo hasn't had service is atleast 10 months, maybe more(wrecker special). it's off right now, had to make sure no little creatures were trying to build in there. would filling the bearing section with oil and letting it sit free it up any faster?
 
If the turbine is not turning freely the engine will suck more air than the turbo can produce. I think your on the right track except that the bearings may be shot. Good Luck. Be sure about the condition...You don't want a turbo coming apart...
 
well, it's time to rebuild. after filling it with oil and letting it sit for a day I found some of the oil went missing. I found it sitting on the the intake time so there's one seal gone. time to invest some more time into it.:mad2: good thing for Bison's rebuild info in the tech section.:thumbsup:
 
much to Aces disappointment. I rebuilt the GM4, not to bad of a job. now I've run into an interesting issues.
My max boost is 5lbs and that's at WOT. the other odd part of it the max EGT's is only 600F. it's about 40F outside.

and yes I tried to get it hot:Justwait2: let's say I hit the governor in 2nd gear.

anybody got a guess as to WHY????

no black smoke, or anything else unusual
 
I considered it but it's doesn't explain the lack of boost. the low boost may be a wastegate that's full of carbon and not seating nicely. I now understand the turbo whistle the 6.5er's talk about. that little sucker can sing when you get on it.
 
homemade TM. I got it to work somewhat but only get boost above the 2k RPM range. the catch is it'll hit 10 in a real hurry. I think it's time for a different spring. as for the EGTs still on the cold side, may turn the pump up a little more.
 
Yeah, a little more fuel may but what it needs. How far of a turn did you turn it previously?

Did you ever post a picture of the homemade TM?
 
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