New Motor?

[6.5L]

Well I purchased an ATT a while back, install went fantastic. Only took four hours but I messed with some other stuff too. A great drop in kit. I am not ragging on the ATT at all but I am having some major spooling issues with the turbo. It will only spool roughly 4-5psi max between 3000rpm and 3500rpm. And even then my pump is de-fueling at 3400rpm. So I have a very brief window. I don't think this is right. I thought maybe I wasn't getting enough fuel so I turned my pump up another quarter turn, so it would be half way in. Nothing at all changed except bad mileage and high EGT's. I cruise down the road at anywhere between 850 and 1000 degree's pre-turbo. Seems very high compared to my GM-3. So I ripped my crossover pipe, it checked out perfectly fine. Checked for intake leaks, still nothing. Checked for exhaust leaks, still came back fine. Somewhere something is gonna give before this works. I just purchased a motor from Teds Trucks. Should be here this week. I thought maybe an injection pump problem delivering fuel, so I am tearing that off and having it sent to Rapid Diesel in Basin for a complete rebuild. I hope it has the upgraded internals for my checkbook's benefit. I am gonna check the turbo this coming week to make sure the internals are ok, and that the wheels are not spinning independently of each other, but I am sure they are fine. I am more convinced of motor than turbo, but who knows. With a 8000lb trailer my boost doesn't change at all and EGT's cross over into the scary point. I can do 80mph and still not build a single PSI. Any suggestions?

 

[NVW]

Those EGT's are excessive, I would suspect the gauge or thermo coupler.

Pull the intake elbow off with engine off and make sure the impeller turns freely.

 

[great white]

Those EGT's are excessive, I would suspect the gauge or thermo coupler.

Pull the intake elbow off with engine off and make sure the impeller turns freely.

I dunno, with only 4-5 psi at 3000-3500 sounds like something else is wrong.

Or both his egt and boost gauge are gone at the same time.

That seems pretty unlikely...

 

[WarWagon]

Why are you throwing parts at it? Engine for sure shot?

Aside from the boost gauge, how does it run vs. the GM3?
Turn the pump back down to get out of scary EGT's or observe what they do with timing.

Lift pump working and pressure verified? A bad lift pump will cause you to loose boost in the upper RPM range even with a GM3.

Don't doubt the EGT gauge. 1/2 turn and big turbo boost lag can put you into scary EGT's. Specifically a GM3 with 1/2 turn on the screw hits 1400 EGT at the factory 6psi. I do not know what the ATT should do here, but, the guage with black smoke would be accurate!

Looks like the IP is delivering fuel. Check the advance piston for movement and use a bar to run it in at idle. Should cause the engine to stumble indicating the advance is working. These pistons stick and could cause you issues. Otherwise I do not see any reason to have the pump checked.

How many miles on the injectors? If rebuilt where and China nozzles?

I would check the timing and reference how it affects turbo's here:
http://www.oliverdiesel.com/tech/timing.htm

 

[NVW]

I thought that too, that's why I suggested checking the turbo vane.

I dunno, with only 4-5 psi at 3000-3500 sounds like something else is wrong.

Or both his egt and boost gauge are gone at the same time.

That seems pretty unlikely...

 

[DZZ71]

Well I purchased an ATT a while back, install went fantastic. Only took four hours but I messed with some other stuff too. A great drop in kit. I am not ragging on the ATT at all but I am having some major spooling issues with the turbo. It will only spool roughly 4-5psi max between 3000rpm and 3500rpm. And even then my pump is de-fueling at 3400rpm. So I have a very brief window. I don't think this is right. I thought maybe I wasn't getting enough fuel so I turned my pump up another quarter turn, so it would be half way in. Nothing at all changed except bad mileage and high EGT's. I cruise down the road at anywhere between 850 and 1000 degree's pre-turbo. Seems very high compared to my GM-3. So I ripped my crossover pipe, it checked out perfectly fine. Checked for intake leaks, still nothing. Checked for exhaust leaks, still came back fine. Somewhere something is gonna give before this works. I just purchased a motor from Teds Trucks. Should be here this week. I thought maybe an injection pump problem delivering fuel, so I am tearing that off and having it sent to Rapid Diesel in Basin for a complete rebuild. I hope it has the upgraded internals for my checkbook's benefit. I am gonna check the turbo this coming week to make sure the internals are ok, and that the wheels are not spinning independently of each other, but I am sure they are fine. I am more convinced of motor than turbo, but who knows. With a 8000lb trailer my boost doesn't change at all and EGT's cross over into the scary point. I can do 80mph and still not build a single PSI. Any suggestions?

ENGINE our trucks have engines!! not MOTORS! Motors are powered by electricity and engines are powerd by fossil fules! sorry for the rant i hope you get your problem figured out.

 

[bk95td]

Sounds to me that you are just throwing parts at it untill you find out what is really wrong. Did you check compression before condemning the engine? Do you have 4" exhaust? Do you have a upgraded air filter? How many miles on the engine and other components? How did it run before you started messing with it? Lots of missing info here for us to help.

 

[Acesneights1]

DB2 delivers less fuel than a DS4 and the spool up even on a GMx is alot slower so maybe the ATT won't work right with that setup ? My 93 spools a little slower than comparable DS4 trucks that had the same GM4. Still wouldn't trade it for a DS4....
I'm not sure if anybody has run an ATT with a DB2 truck ???

 

[buddy]

Turn the pump back down to get out of scary EGT's or observe what they do with timing.

Looks like the IP is delivering fuel. Check the advance piston for movement and use a bar to run it in at idle. Should cause the engine to stumble indicating the advance is working. These pistons stick and could cause you issues. Otherwise I do not see any reason to have the pump checked.

How many miles on the injectors? If rebuilt where and China nozzles?

I would check the timing and reference how it affects turbo's here:
http://www.oliverdiesel.com/tech/timing.htm

Determining if the DB2's advance is working would be my first move. I would suspect it is not advancing, leaving it retarded and not getting a good burn of the extra fuel.

The GMx turbos spool very very easily in comparison to a turbo as large as the ATT. The wheels are larger and the housings are significantly larger.

 

[6.5L]

Yes, I have also checked the advance is working on my injection pump. I have a 4in exhaust, AFE Stage II intake, and it has 370,000 miles on the original motor. I have no idea how old the injection pump and injectors are. I have previously thrown 21psi of boost at it from my GM-3 and my head gaskets intact still, making me suspect my compression has gone down a little. I think part of it may be the injection pump. At 1600rpm in any gear I'm at, the motor will start to surge almost, like it's "missing". But only if I keep it at 1600rpm. The truck has always done this, and it gets worse under load. I think something somewhere is wrong and I just may think it's the injection pump. I could be wrong. Another reason I bought the new ENGINE is because our other 1993 6.5L motor took a crap this last weekend so I am gonna give my dad the motor that is in my truck that works wonders with the gm-3 and I am gonna use the one from Teds Trucks. So it works out decent either way.