2000 GMC 3500 6.5l runs good no power

[electrodude]

HI: Guys, I have a 2000 GMC 3500 automatic 4x4 mason dump with 60k miles, new lift pump, new injectors, new glow plugs, relocated PMD, new fuel filter, new rubber fuel lines to injector pump, injection pump timing is -75. no smoke. it seems to run good but has no power. Going up a hill it's hard to make 50mph empty. The trans shifts up through all the gears, but doesn't seem to want to kick down when flooring it, It does shift down when I come to a stop and start off again, It starts right up and runs smooth, throttles up no issue in park. I was wondering if the optical sensor could cause the trans not to kick down or some other sensor. Seems like it should kick down to a lower gear to me? Any help would be appreciated Thanks Mike

 

[Wreckinball67]

Might check the turbo. Sounds like it's not boosting. Check vacuum from the vacuum pump, should be 17-19Hg (approx). Also check hard vac lines (tend to crack) from vac pump to solenoid. Also check vacuum at turbo, I forget what the Hg should be there.
I've had similar issues, wound up changing the pressure sensor mounted on the firewall near the brake booster then my issues were gone.

 

[MrMarty51]

If the timing is set at -75. Then that would be all wrong.
If it is -0.75 then it is good.
The DOT over here had duallys with the dump bed and a huge front board on the box with an overhang.
Those things didnt seem like they had a lot of power just because of the wind resistance.
If Your truck has a huge front board on the box, that could be part of the problem.
If it has the board and if it is bolted on, try removing it then go for a drive.
Watch for black smoke out the pipe. If it is producing a lot of black smoke then it will be as @Wreckinball67 mentioned about the turbo not functioning.

 

[WarWagon]

Did it EVER run better? Check for codes as transmission codes do not trip a light. X2 on look at the exhaust.

These engines loose power over 2200 RPM as the turbo chokes the hell out of the engine with extreme backpressure. IMO not downshifting is an improvement with the factory turbo as it's "all blow and no go" revved up.

The 6.5L Diesel Factory Equipped Asthma Attack

Online Diesel Community featuring news and articles on 6.2L, 6.5L and Duramax GM diesel engines, Ford Powerstroke, Chevy Cruise, lubrication and more.

www.maxxtorque.com

 

[electrodude]

If the timing is set at -75. Then that would be all wrong.
If it is -0.75 then it is good.
The DOT over here had duallys with the dump bed and a huge front board on the box with an overhang.
Those things didnt seem like they had a lot of power just because of the wind resistance.
If Your truck has a huge front board on the box, that could be part of the problem.
If it has the board and if it is bolted on, try removing it then go for a drive.
Watch for black smoke out the pipe. If it is producing a lot of black smoke then it will be as @Wreckinball67 mentioned about the turbo not functioning.

Sorry -0.75 timing

 

[electrodude]

If the timing is set at -75. Then that would be all wrong.
If it is -0.75 then it is good.
The DOT over here had duallys with the dump bed and a huge front board on the box with an overhang.
Those things didnt seem like they had a lot of power just because of the wind resistance.
If Your truck has a huge front board on the box, that could be part of the problem.
If it has the board and if it is bolted on, try removing it then go for a drive.
Watch for black smoke out the pipe. If it is producing a lot of black smoke then it will be as @Wreckinball67 mentioned about the turbo not functioning.

Sorry -0.75 timing

 

[electrodude]

Sorry -0.75 timing

No big box on mason dump

 

[electrodude]

Did it EVER run better? Check for codes as transmission codes do not trip a light. X2 on look at the exhaust.

These engines loose power over 2200 RPM as the turbo chokes the hell out of the engine with extreme backpressure. IMO not downshifting is an improvement with the factory turbo as it's "all blow and no go" revved up.

The 6.5L Diesel Factory Equipped Asthma Attack

Online Diesel Community featuring news and articles on 6.2L, 6.5L and Duramax GM diesel engines, Ford Powerstroke, Chevy Cruise, lubrication and more.

www.maxxtorque.com

I bought it to use as a plow, run around, go to the dump, fill potholes truck. It didn't run when I bought it, bad lifter, which I replaced. After I replaced the lifter it started right up but Smoked like a steam engine. Turns out that the previous owner reversed 5 and 7 injector line, don't know how, they are hard steel.fixed that, no more smoke. So I don't know how it ran previously.

 

[electrodude]

Did it EVER run better? Check for codes as transmission codes do not trip a light. X2 on look at the exhaust.

These engines loose power over 2200 RPM as the turbo chokes the hell out of the engine with extreme backpressure. IMO not downshifting is an improvement with the factory turbo as it's "all blow and no go" revved up.

The 6.5L Diesel Factory Equipped Asthma Attack

Online Diesel Community featuring news and articles on 6.2L, 6.5L and Duramax GM diesel engines, Ford Powerstroke, Chevy Cruise, lubrication and more.

www.maxxtorque.com

Could cat be clogged? Exhaust comes out, seem ok

 

[electrodude]

Might check the turbo. Sounds like it's not boosting. Check vacuum from the vacuum pump, should be 17-19Hg (approx). Also check hard vac lines (tend to crack) from vac pump to solenoid. Also check vacuum at turbo, I forget what the Hg should be there.
I've had similar issues, wound up changing the pressure sensor mounted on the firewall near the brake booster then my issues were

waste gate seems to work ok, i put a vac gauge on the vac line at turbo , not sure how to test the turbo itself?

 

[electrodude]

waste gate seems to work ok, i put a vac gauge on the vac line at turbo , not sure how to test the turbo itself?

It's putting out air, air filter is clean too

 

[electrodude]

I bought it to use as a plow, run around, go to the dump, fill potholes truck. It didn't run when I bought it, bad lifter, which I replaced. After I replaced the lifter it started right up but Smoked like a steam engine. Turns out that the previous owner reversed 5 and 7 injector line, don't know how, they are hard steel.fixed that, no more smoke. So I don't know how it ran previously.

Is there a special scanner for transmission codes

 

[electrodude]

Sorry -0.75 timing

It is a daully

 

[dbrannon79]

a simple way to check the turbo wastegate is while the engine is idling, try to move the arm by hand. it should be sucked in by the vacuum actuator and extremely hard to move with your hand. next check the turbo. remove the air cleaner rubber hose on the intake side of the turbo. verify that there is absolutely nothing that can get sucked into the turbo, dirt leaves, anything. while the engine is off. with your fingers check up down side to side play on the turbo impeller while turning it in the housing. if it touches or scrapes the housing your turbo is in need of a rebuild or replacement. next. with the rubber hose removed from the turbo, crank it up and look (NO TOUCH) the turbo impeller. it should be spinning fast at idle. rev it up a few times and you should hear it spool and whistle. take it down the road simulating the issue and listen for the turbo whistling higher and higher. if when it seems to have a loss in power you hear the turbo slowing down, this can mean a couple if things. 1. its over boosting and the PCM is de-rating the fuel and boost by means of the wastegate and IP, will also sometimes set a code. (need to install a boost gauge to verify) 2. the wastegate solenoid is bad and not holding vacuum to the actuator or the vacuum pump is not pulling enough vacuum for it.. this is where it might be useful to get a scanner that can read live data from the PCM. since you have a 2000 model, a Bluetooth adapter and the torque pro android app should work to see codes and live data.

 

[MrMarty51]

If You have, or can borrow/rent one from a parts store. Get a vacuum pump. Connect it to the waste gate actuator, when applying and releasing vacuum, the arm should move.
The vacuum pump can be hooked to the vacuum tube going to the vacuum pump mounted to the engine.
with the vacuum release valve on the hand held pump in the closed position, You should have a vacuum reading of around 30” of vacuum with the engine running. If it is about 20” of vacuum, replace the vacuum pump on the engine.

 

[ak diesel driver]

Actually max vacuum should be around 22

 

[MrMarty51]

Actually max vacuum should be around 22

I guess at sea level about 32” is maximum vacuum available.

 

[electrodude]

If You have, or can borrow/rent one from a parts store. Get a vacuum pump. Connect it to the waste gate actuator, when applying and releasing vacuum, the arm should move.
The vacuum pump can be hooked to the vacuum tube going to the vacuum pump mounted to the engine.
with the vacuum release valve on the hand held pump in the closed position, You should have a vacuum reading of around 30” of vacuum with the engine running. If it is about 20” of vacuum, replace the vacuum pump on the engine.

I tested for vacuum at the waste gate it's about 25in vac. The waste gate is very hard with vac and easy with out vac, actuator seems to be fine, some play in in turbo fan side to side , but not hitting anything. Ill have to install a boost gauge and see what is happening there. I'll have to try taking hose off and listening for the tur o spool up whistle. Thanks Mike

 

[MrMarty51]

For diagnostics, I run two vacuum gauges Td in at the WG solenoid, then the gauges hosed out to either in tje cab or under the windshield wiper arm where the will be secure.
Go for a drive and watch the gauges, making sure that the solenoid is functioning by the vacuum between the solenoid and the WG actuator.

 

[electrodude]

For diagnostics, I run two vacuum gauges Td in at the WG solenoid, then the gauges hosed out to either in tje cab or under the windshield wiper arm where the will be secure.
Go for a drive and watch the gauges, making sure that the solenoid is functioning by the vacuum between the solenoid and the WG actuator.

Whats Td in? Turbo in take? I know waste gate actuator, where does the boost gauge vac tie in, Intake after turbo? Thanks. Mike