Backfire Issue
Thread Starter
Teching In
Joined: Sep 2013
Posts: 27
Likes: 5
From: Maryland, USA
Backfire Issue I am hoping someone can help me. I have a stock, carbureted, LQ4 in my 69 Camaro. It has the MSD computer for timing and headers but otherwise it is stock. The engine has been in the car for 2 years now but I have noticed this recently.
The engine idles and accelerates fine but when slowing down and especially downshifting, the car backfires through the exhaust.
I have not done any digging around the engine yet to discover the issue but I have a feeling it is a broken valve spring. I did overheat the engine when I first put it in the car 2 years ago and I have heard that springs get brittle when that happens.
Has anyone experienced this or have any ideas what is going on? Right now I do not have any convenient way to work on it so I am just trying to think all the scenarios where this could happen.
Thanks for any help.
The engine idles and accelerates fine but when slowing down and especially downshifting, the car backfires through the exhaust.
I have not done any digging around the engine yet to discover the issue but I have a feeling it is a broken valve spring. I did overheat the engine when I first put it in the car 2 years ago and I have heard that springs get brittle when that happens.
Has anyone experienced this or have any ideas what is going on? Right now I do not have any convenient way to work on it so I am just trying to think all the scenarios where this could happen.
Thanks for any help.
After Burn YOUR case is NOT "backfire" it is After Burn.
The "pop" from the exhaust, as you state, is from fuel burning in the exhaust pipes.
MY first "tech" would be to close the throttle plates, check the "secondary" plate.
Then check the Float Level.
Lance
The "pop" from the exhaust, as you state, is from fuel burning in the exhaust pipes.
MY first "tech" would be to close the throttle plates, check the "secondary" plate.
Then check the Float Level.
Lance
