No boost to vary low boost

[gn dennis]

Took my Buick out for a ride started to slow roll into it and boost did not come on. The next time watching boost gauge got on it, boost pressure only went up about 5psi. put car in garage let it cool down. This is what I have checked so far. Pressure checked actuator works good, Removed exhaust elbow looks ok, I don't know how to check the switch on passenger side valve cover. Turbo turns freely, I have owned this Buick for 7 years. Please need help. Thanks vary mech Dennis

 

[notacarlo]

can you hear it spool despite no accelleration? I'd check all your soft connection in the charge air tract.

 

[gn dennis]

can you hear it spool despite no accelleration? I'd check all your soft connection in the charge air tract.

can you hear it spool despite no accelleration? I'd check all your soft connection in the charge air tract.

No I cant hear it spooling. But I cant ever hear spool, you can tell when its right by the seat of your pants. Thanks

 

[notacarlo]

was the wastegate puck and arm still attached to the shaft, meaning it moves with the shaft and not independent of it?

 

[gn dennis]

was the wastegate puck and arm still attached to the shaft, meaning it moves with the shaft and not independent of it?

Yes It is attached, I took a straight edge to puck looks flat as does the mating surfaces of the elbow and exhaust side of cast iron elbow. I just removed the pipe coming out of the cooler to inlet of engine looks good. Thanks

 

[ScottHeidinger]

If you don’t have any cracks in your headers then there may be a restriction in your exhaust. The cat could be clogged if there is one on the car. Do you have a scan tool?


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[gn dennis]

If you don’t have any cracks in your headers then there may be a restriction in your exhaust. The cat could be clogged if there is one on the car. Do you have a scan tool?


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Thanks Scott no cat, haven't checked for cracks car not running, can I check headers another way?

 

[hensleyt]

Wastegate switch on valve cover dose it have a port open I think it faces forward. This port needs to be open no plug, at onetime it had a small filter

 

[gn dennis]

Thanks Scott no cat, haven't checked for cracks car not running, can I check headers another way?
[/I am trying to post pictures they on in my email. HELP

 

[gn dennis]

Wastegate switch on valve cover dose it have a port open I think it faces forward. This port needs to be open no plug, at onetime it had a small filter

No plug, trying to post pictures need help. Thanks

 

[No disintegrations]

If it runs good off boost, I'd suspect cracked headers or other exhaust leak. They will make a ticking sound when in gear under a load. Could also be wastegate not closing. It should be closed until target boost is made, then it opens. One other thing, I've never seen this myself but remember a thread or 2 where really low fuel delivery caused the engine to drag ass and run weak with low boost.

 

[gn dennis]

No plug, trying to post pictures need help. Thanks

If it runs good off boost, I'd suspect cracked headers or other exhaust leak. They will make a ticking sound when in gear under a load. Could also be wastegate not closing. It should be closed until target boost is made, then it opens. One other thing, I've never seen this myself but remember a thread or 2 where really low fuel delivery caused the engine to drag ass and run weak with low boost.

I just finished replacing the gasket to turbo to down pipe. Is that considered an exhaust leak? Thanks

 

[NY Twin Turbo]

I just finished replacing the gasket to turbo to down pipe. Is that considered an exhaust leak? Thanks

Exhaust leaks after the turbo do not effect spool-up. So no.

 

[precizion818]

I had this problem and it turned out to be a leaking intake gasket. Boost was leaking into the crankcase blowing the oil dip stick out slightly. Replaced the gasket and was good.

I would perform a boost leak test From the inlet of the turbo.


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[gn dennis]

Exhaust leaks after the turbo do not effect spool-up. So no.

Thanks Joe I think the exhaust elbow on turbo is wrong. I would post pictures cant figure out how to. How ever this el has been on the turbo for 7 years. The machined surfaces don't match up, bolts up good, can el be clocked different?

 

[John Larkin]

Put a thin layer of antisieze on the elbow surface, install it then remove and see what pattern is on there. Probably fine. You might check the puck to ensure it covers the hole, same thing with the antisieze.

 

[TurboBuRick]

An exhaust leak would have to be pre turbo and pretty extreme to cause a no boost condition. Like the crossover pipe blew apart or the bolts came out of a flange.

Check all the intercooler couplings?

Inspect the intercooler? What intercooler is it?

 

[gn dennis]

I had this problem and it turned out to be a leaking intake gasket. Boost was leaking into the crankcase blowing the oil dip stick out slightly. Replaced the gasket and was good.

I would perform a boost leak test From the inlet of the turbo.


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Thanks will check that. The car was noise down pipe side there was noise

Put a thin layer of antisieze on the elbow surface, install it then remove and see what pattern is on there. Probably fine. You might check the puck to ensure it covers the hole, same thing with the antisieze.

I put turbo and down pipe back together took the car for a ride boost is working rising slower and only going to 10psi. Max pressure has always been 15psi. I will keep looking, Thanks John

 

[precizion818]

When I had that problem.... boost was slow and would max out at like 7 psi


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[gn dennis]

When I had that problem.... boost was slow and would max out at like 7 psi


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How do you perform a boost leak test? Thanks