free hit
counters
backfiring - Fuel System/Carbs - The Lotus Forums Jump to content
paulbutvila

backfiring

Recommended Posts

I noticed my float was sitting in the bowl crooked due to a broken tab that holds the pivot pin for the float. This was on cylinders 3&4. Also, # 2,3,&4 cylinders are running rich. Would this problem cause the car to backfire repeatedly during downshifting?

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Wasn't it... I fixed the Float problem and it is still backfiring while decelerating...got any more thoughts. More than likely a carb issue I would think

Electrical maybe?

Share this post


Link to post
Share on other sites

Just to alleviate any questions, this is an exhaust backfire rather than backfiring through the carb right? for exhaust backfire, rich will generally cause that either because too much fuel is being introduced into the compression chamber (carb problem), or you have a misfire (even minor) causing unburned fuel to enter the exhaust system. I'd check the plugs, wires and distro cap. Hooking up a vacuum gauge can also give a good deal of information and can help diagnose an ignition problem (jumping needle can indicate misfire).

Share this post


Link to post
Share on other sites

Yes, exhaust backfire. Very minor leaks in the exhaust system. Cylinders 3,4,5 very rich. New plug wires and plugs have been installed. I visually checked the dist. cap and internal bits everything looks good there. I am hoping it is just a carb adjustment that needs to be taken care of. Gotta guy dropping by tomorrow morning to adjust the carbs. I will keep you posted as to his findings...

Share this post


Link to post
Share on other sites

I would be more inclined to agree with the leaking exhaust as the cause. I had a backfire on downshifts and overrun on my '87 Turbo HC and it turned out to be worn exhaust valves. Also had a similar problem on an '85 Suzuki GSXR750 which was caused by a very small hole in an exhaust downpipe.

Sort out the leaks in the exhaust (I would probably focus near the head) and I suspect you will cure the backfire.

cheers

-Chris

Share this post


Link to post
Share on other sites

Checked out the exhaust system..everything is just fine in that dept...got any other ideas?

Share this post


Link to post
Share on other sites

Electronic ignition...I am more inclined to say it is carbs than anything. The car ran fine prior to getting some crap from the old tanks sucked into the carbs before shutting it down and having new ones fabricated. I think there was some old (dirty ) gas sitting in the carbs for about 6 months. I am having a guy rebuild the carbs this weekend ( i hope ) so that may solve my proble. I will keep you posted...

Share this post


Link to post
Share on other sites

Finally...heres the scoop...

It was a leak in the vac. line from the head to the master brake cylinder. Somewhere down the alluminum pipe that runs through the tunnel had a hole in it. So I simply ran a new line and the problem was solved.Carbs had an overhaul also. This all got rid of my not being able to rev the car over 5000RPM and the very annoying back firing. The car now revs all the way to max revs. I am very happy. Now I need to address my rear rotors, need two of em'

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×