Power Loss
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 1,218
Likes: 70
Power Loss
Looking to figure out what happened:
02 Z06 w/25K
Cam/Exhaust
A&A Ti (1500 Miles Ago)
611/532
Engine began to burn excessive oil last few weeks.
Was going 75 today on highway, did 3/4 throttle in 4th, began to pick up speed and sudden loss of power.
Power remains lost, however I can cruise on cruise control at 80mph (Wyoming speed limit).
Car can still pick up, but struggles to build RPM.
Car struggles to get into boost if it even does (no boost gauge).
Feels less powerful than when cam only car.
Waste gate seems to still be working as normal.
First thought is a ring went and no compression, but my knowledge is minimal.
No basic things, like intake hose off or anything simple that I can tell.
No codes.
02 Z06 w/25K
Cam/Exhaust
A&A Ti (1500 Miles Ago)
611/532
Engine began to burn excessive oil last few weeks.
Was going 75 today on highway, did 3/4 throttle in 4th, began to pick up speed and sudden loss of power.
Power remains lost, however I can cruise on cruise control at 80mph (Wyoming speed limit).
Car can still pick up, but struggles to build RPM.
Car struggles to get into boost if it even does (no boost gauge).
Feels less powerful than when cam only car.
Waste gate seems to still be working as normal.
First thought is a ring went and no compression, but my knowledge is minimal.
No basic things, like intake hose off or anything simple that I can tell.
No codes.
Last edited by Water_Walker; May 23, 2017 at 09:54 PM.
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 1,218
Likes: 70
Acct Suspended APR 2026 by request
Joined: Dec 2010
Posts: 10,367
Likes: 1,272
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
my first guess was also broken ring land seeing that the car is boosted, that would explain the oil consumption and power loss but it could be a lot of things... pull the plugs and see if any of them look abnormal compared to the others, that will help narrow down what cylinder(s) you need to pay attention to... if you have a borescope you can look down in the cylinder and see if there is any physical damage or you could do a leakdown test
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Do you have any excessive crank case blow-by? Pull off the oil fill plug and see if there is any crank case gasses spewing out of the oil fill hole.
Do a cylinder lead down test.
Clogged cats will also cause a loss of power and low boost.
Even though you have aftermarket springs, I would still pull the valve covers and do a very close valve spring inspection.
Bill
Do a cylinder lead down test.
Clogged cats will also cause a loss of power and low boost.
Even though you have aftermarket springs, I would still pull the valve covers and do a very close valve spring inspection.
Bill
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 1,218
Likes: 70
I thought I would try again.
I pulled the plugs and everything looks fine. Put new plugs in, since old were out.
I do not have a boost gauge, but I am almost sure there is no boost whatsoever. What would cause a car to have no boost. I checked all the charge piping and everything looks intact.
I hear no unusual sounds from the motor or value train.
I did take the car out for about 1 mile to see if it would get into boost and I do not think it does. It seemed hot under the hood for a 1 mile trip.
t-trim makes the normal/minimal whine. If I put my ear near the head unit, it sounds like marbles in a can. I cannot tell if this is a normal sound internal to a supercharger or something wrong.
What about a bad wastegate? What would be the symptoms of that?
Still looking for guidance...
I pulled the plugs and everything looks fine. Put new plugs in, since old were out.
I do not have a boost gauge, but I am almost sure there is no boost whatsoever. What would cause a car to have no boost. I checked all the charge piping and everything looks intact.
I hear no unusual sounds from the motor or value train.
I did take the car out for about 1 mile to see if it would get into boost and I do not think it does. It seemed hot under the hood for a 1 mile trip.
t-trim makes the normal/minimal whine. If I put my ear near the head unit, it sounds like marbles in a can. I cannot tell if this is a normal sound internal to a supercharger or something wrong.
What about a bad wastegate? What would be the symptoms of that?
Still looking for guidance...
Last edited by Water_Walker; Jun 5, 2017 at 10:14 PM.
Acct Suspended APR 2026 by request
Joined: Dec 2010
Posts: 10,367
Likes: 1,272
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
check to make sure the bov is open at idle and closing as you reach near zero vacuum, when it closes that will allow you to build boost... if the valve is stuck open it will be a major boost leak... you can also try to figure out a way to pressurize the system with about 10-15psi of compressed air and you should be able to hear where the leak is coming from
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 1,218
Likes: 70
check to make sure the bov is open at idle and closing as you reach near zero vacuum, when it closes that will allow you to build boost... if the valve is stuck open it will be a major boost leak... you can also try to figure out a way to pressurize the system with about 10-15psi of compressed air and you should be able to hear where the leak is coming from
Correct me if I am wrong, but I would hear it if it was always open just the same correct?...Meaning, if it was stuck open would I not hear it under heavy throttle?
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