Low Vac, Low boost?
08-25-2009, 11:28 PM
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Low Vac, Low boost?
Hi,
Normally on my car, I would get -20hg at idle, and fully boosted is 15psi
Tonight I was booting it a little on the highway, felt a little slow, I looked at my boost guage and i was only reading 4psi
I pull off, get to a light, and see at idle i get maybe only -6hg, and when floored, maybe 1psi
You can still hear the turbo spool like a champ, car still drives pretty flawlessly, minus the boost
What could it be?
Would a faulty wastegate cause this?
Normally on my car, I would get -20hg at idle, and fully boosted is 15psi
Tonight I was booting it a little on the highway, felt a little slow, I looked at my boost guage and i was only reading 4psi
I pull off, get to a light, and see at idle i get maybe only -6hg, and when floored, maybe 1psi
You can still hear the turbo spool like a champ, car still drives pretty flawlessly, minus the boost
What could it be?
Would a faulty wastegate cause this?
Last edited by vtak2nr; 08-26-2009 at 01:24 PM.
08-26-2009, 05:24 PM
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Re: Low Vac, Low boost?
if your vac dropped and the boost dropped at the same time, it has to be a vac leak. if they didnt happen at the same time, there could be 2 separate issues.
go over all your post throttle body vacuum fittings and gaskets. use some carb cleaner, spray around and listen for the rpm change.
go over all your post throttle body vacuum fittings and gaskets. use some carb cleaner, spray around and listen for the rpm change.
08-26-2009, 05:42 PM
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Re: Low Vac, Low boost?
sounds like a vacuum leak and a charge pipe came off or just the vacuum leak. generally you should be able to build more boost than that with just a vacuum line off thats why i think might be two things
08-26-2009, 11:23 PM
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Re: Low Vac, Low boost?
At idle the car is fine. Just my guage reads -6hg rather than the normal -20hg. RPMs dont fluctuate (as ive seen other cars with vacuum leaks do)
Infact the car still drives perfectly fine, minus the loss in power, it is still definately driveable
I tried looking//listening//feeling for a leak with the car idling but didnt find anything. Re-tightened all my boost pipes, same thing.
How would I go about checking a vacuum leak with everyday items? (i only have basic socket//wrench sets at home, nothing pro...)
Infact the car still drives perfectly fine, minus the loss in power, it is still definately driveable
I tried looking//listening//feeling for a leak with the car idling but didnt find anything. Re-tightened all my boost pipes, same thing.
How would I go about checking a vacuum leak with everyday items? (i only have basic socket//wrench sets at home, nothing pro...)
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08-27-2009, 12:39 AM
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Re: Low Vac, Low boost?
At idle the car is fine. Just my guage reads -6hg rather than the normal -20hg. RPMs dont fluctuate (as ive seen other cars with vacuum leaks do)
Infact the car still drives perfectly fine, minus the loss in power, it is still definately driveable
I tried looking//listening//feeling for a leak with the car idling but didnt find anything. Re-tightened all my boost pipes, same thing.
How would I go about checking a vacuum leak with everyday items? (i only have basic socket//wrench sets at home, nothing pro...)
Infact the car still drives perfectly fine, minus the loss in power, it is still definately driveable
I tried looking//listening//feeling for a leak with the car idling but didnt find anything. Re-tightened all my boost pipes, same thing.
How would I go about checking a vacuum leak with everyday items? (i only have basic socket//wrench sets at home, nothing pro...)
if your vac dropped and the boost dropped at the same time, it has to be a vac leak. if they didnt happen at the same time, there could be 2 separate issues.
go over all your post throttle body vacuum fittings and gaskets. use some carb cleaner, spray around and listen for the rpm change.
go over all your post throttle body vacuum fittings and gaskets. use some carb cleaner, spray around and listen for the rpm change.
08-27-2009, 03:59 AM
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Re: Low Vac, Low boost?
while the engine is running take a can of brake cleaner and spray around the inatek manifold where the vacuum portsd are and throttle body and where it meets the head. if the engine revs up find the leak source that way and your problem is solved.
if the engine isnt on a high idle then it probably doesnt have a vacuum leak and could just be a boost pipe is not connected OR you've lost compression in more than one cylinder. do at least a compression test on a warm engine and see what numbers you come up with. if you have a leak down tester than do a leak down as well
if the engine isnt on a high idle then it probably doesnt have a vacuum leak and could just be a boost pipe is not connected OR you've lost compression in more than one cylinder. do at least a compression test on a warm engine and see what numbers you come up with. if you have a leak down tester than do a leak down as well
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