Backfire issue. this is killing me
Thread Starter
Instructor
Joined: Jun 2005
Posts: 248
Likes: 1
From: Apopka Florida
Backfire issue. this is killing me
I have the timing set at 36 at 2500 rpms. The first 20 minutes or so I have backfire issues when punched. After the car heats up and about 20 minutes later it runs perfect. Any suggestions as to what is causing this problem and how to correct it. I did change the springs to medium which where heavy before but that didn't seem to make a difference. By the way 73' 454 engine. New plugs and 18.5 msd wires. Thanks for any help.
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by BigBlockk
Backfiring is a lean condition.
Backfiring (popping up through the carb) is a lean condition. In addition to having a weak pump shot, you may also need to correct jetting for a slightly richer setup. However, if you are not running a choke (do you have a choke?), it is normal and common to have a lean backfire condition when punched prior to full warm-up.
Instructor
Joined: Oct 2004
Posts: 132
Likes: 0
From: NC
Try this. Start engine when its dark outside (very dark). Let it idle. Look closely to ensure there is no spark jumping from bad or burnt spark plug wires
I have had that prob a couple of times over the years. Look closely for arcing. In HEI you can actually hear it arcing. I didnt get popping at idle, but did out on the road when I had bad wires that were arcing
You never know!
I have had that prob a couple of times over the years. Look closely for arcing. In HEI you can actually hear it arcing. I didnt get popping at idle, but did out on the road when I had bad wires that were arcing
You never know!
