Bad Turbo Symptoms

Goad

Member
Feb 29, 2020
73
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8
Las Vegas, NV
Just did my injectors (SAC45's)....balance rates are good. Compression check is good too.

After a long idle (5-10 min) there is a light smoke that starts to appear from the exhaust. When I drive it, it just billows out of the exhaust.

There is no sign of a ton of oil residue in the downpipe....or charger pipes.

Back story: This is a new/used motor I just installed. First motor died due to major head gasket failure. The new/used motor did not come with a turbo. The turbo in question is the one that was on the motor when the head gasket failed. It wasn't inspected, just swapped over.

If it is the turbo, should I rebuild it or purchase a new one?

It is a CA Emissions Motor and turbo.
 

Bdsankey

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Feb 1, 2018
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Does the truck have a ton of blowby? Is the CCV breathing properly and not plugged? I had a customer who did a CCV reroute (obviously not on an LB7) but he decided to simply run the two lines together and not vent them to the atmosphere which caused the truck to white smoke pretty bad, nothing seemed to be permanently damaged tho (turbo wasn't puking oil nor was anything else).
 

Goad

Member
Feb 29, 2020
73
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8
Las Vegas, NV
Is your tune adjusted for the SAC45s?

Short answer is no. I know there is some hazing to be expected when running the SAC's on a tune that isnt made for them. I am not sure what tune is in the truck. It came with a PPE tuner, but when I plug it in, it says VIN Mismatch, but the VIN on the screen matches the truck.

Does the truck have a ton of blowby? Is the CCV breathing properly and not plugged? I had a customer who did a CCV reroute (obviously not on an LB7) but he decided to simply run the two lines together and not vent them to the atmosphere which caused the truck to white smoke pretty bad, nothing seemed to be permanently damaged tho (turbo wasn't puking oil nor was anything else).

It's not getting a ton of blowby...the CCV is routed the same way it always has been. I didnt change anything on that.

Something I want to point out again. When its cold, it doesnt smoke. Once it warms up, it starts to smoke during idle. When I drove it down the street, I couldn't see the end of the street behind me. It doesnt smell like fuel.

So what are the symptoms of a bad turbo? Am I going down the wrong rabbit hole?
 

Bdsankey

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If it's not wet in the downpipe/CAC plumbing I would pressure test the cooling system. If that doesn't show leaks I'd then get the truck tuned for the SAC45s.
 

Goad

Member
Feb 29, 2020
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Las Vegas, NV
Any tips or advice on how to properly test the cooling system?

Edit: This truck has an EGR. Should I be testing that as well?
 

Bdsankey

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Any tips or advice on how to properly test the cooling system?

Edit: This truck has an EGR. Should I be testing that as well?

Buy or rent a coolant pressure tester. It screws onto the overflow bottle and pressurizes the system. You're looking for ~15psi and watch how long it holds. It should never drop.
 

Bdsankey

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A kit like the first link, I cannot confirm if the Harbor Freight kit has the adapter for threaded GM bottles but I'd imagine so.
 
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Goad

Member
Feb 29, 2020
73
3
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Las Vegas, NV
So I pressurized the system at cold at 10lbs and it puked coolant out of the connectors to the heater core. I pulled those connectors off and hooked them up directly to the core. Then re-pressurized the system....and it held 10lbs for 20+ minutes. Gauge didn't budge.

Should I run the truck starting it cold and at zero pressure and see if I gain pressure over time?
 

snowman22

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Jan 30, 2018
298
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18
SoCal
Block the EGR and see what happens. If it's opening after warming up and not closing until shutdown it could cause the issue. Is it able to make boost?