Backfire
Thread Starter
Drifting
Joined: Oct 1999
Posts: 1,669
Likes: 98
From: Jacksonville FL
Backfire
I'm getting backfiring when at idle or mild throttle application. Does not occur at half throttle and above nor on decel. This has started to occur after replacing a faulty oil and water pump. Also getting a ticking noise from under the hood that increases with engine RPM. Any ideas where to start? Thanks.
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
LS engines are very sensitive to a cylinder miss. When you get the backfire, see if you get a FLASHING (Check Engine Light). Also, during the event (without turning the ignition off), enter the DIC Code checking routine and see if you have a PCM P-0300 C or H code.
That indicates that you have enough misfires to trip the DTC.
With the engine noise, you could have a:
BAD Plug Wire
OR
A damaged valve spring
OR
Bad Coil
OR
Bad Spark Plug
Give all those a look and make sure that you don't have a loose plug wire or bad wire first.
Bill
That indicates that you have enough misfires to trip the DTC.
With the engine noise, you could have a:
BAD Plug Wire
OR
A damaged valve spring
OR
Bad Coil
OR
Bad Spark Plug
Give all those a look and make sure that you don't have a loose plug wire or bad wire first.
Bill
Last edited by Bill Curlee; Jan 28, 2015 at 08:50 PM.
Racer
Joined: Oct 2003
Posts: 491
Likes: 1
From: Owasso OK
I'm getting backfiring when at idle or mild throttle application. Does not occur at half throttle and above nor on decel. This has started to occur after replacing a faulty oil and water pump. Also getting a ticking noise from under the hood that increases with engine RPM. Any ideas where to start? Thanks.
Thread Starter
Drifting
Joined: Oct 1999
Posts: 1,669
Likes: 98
From: Jacksonville FL
LS engines are very sensitive to a cylinder miss. When you get the backfire, see if you get a FLASHING (Check Engine Light). Also, during the event (without turning the ignition off), enter the DIC Code checking routine and see if you have a PCM P-0300 C or H code.
That indicates that you have enough misfires to trip the DTC.
With the engine noise, you could have a:
BAD Plug Wire
OR
A damaged valve spring
OR
Bad Coil
OR
Bad Spark Plug
Give all those a look and make sure that you don't have a loose plug wire or bad wire first.
Bill
That indicates that you have enough misfires to trip the DTC.
With the engine noise, you could have a:
BAD Plug Wire
OR
A damaged valve spring
OR
Bad Coil
OR
Bad Spark Plug
Give all those a look and make sure that you don't have a loose plug wire or bad wire first.
Bill
Thanks Bill. We have changed all of the plugs and wires recently. Will check the connections. I feared it might be a spring as the Stage 2 Katech heads and cam package is getting up there in the years.
----
Mike
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
Mike
Bad Spring or bad intake valve QUICK CHECK:
I you have an inferred laser thermometer, use it to measure the temperature of each intake manifold runner right where it connects to the head.
They should all be about the same temp. If you have a bad intake valve spring or valve and the valve is leaking by, that runner will have a much higher temp than the rest.
Bill
Bad Spring or bad intake valve QUICK CHECK:
I you have an inferred laser thermometer, use it to measure the temperature of each intake manifold runner right where it connects to the head.
They should all be about the same temp. If you have a bad intake valve spring or valve and the valve is leaking by, that runner will have a much higher temp than the rest.
Bill
Thread Starter
Drifting
Joined: Oct 1999
Posts: 1,669
Likes: 98
From: Jacksonville FL
Mike
Bad Spring or bad intake valve QUICK CHECK:
I you have an inferred laser thermometer, use it to measure the temperature of each intake manifold runner right where it connects to the head.
They should all be about the same temp. If you have a bad intake valve spring or valve and the valve is leaking by, that runner will have a much higher temp than the rest.
Bill
Bad Spring or bad intake valve QUICK CHECK:
I you have an inferred laser thermometer, use it to measure the temperature of each intake manifold runner right where it connects to the head.
They should all be about the same temp. If you have a bad intake valve spring or valve and the valve is leaking by, that runner will have a much higher temp than the rest.
Bill
Will do. Thanks again Bill.
----
Mike
