I am experiencing a bit of a back fire on my 512TR. And I wonder what could cause it. The car ran fine with 2 near death spark plugs and old fuel filters. The car started to back fire with new rally-type fuel filters. So, I decided to change all the spark plugs. The car now idles smoothly with no back fire, but once the engine is up to temperature, I still have a few back fire once in a while during the coasting down. We checked the spark plug wires and they are all OK. I wonder if the back fire has anything to do with the rally car type fuel filter? The car seems to run much richer mixture. I have removed the cat before any of this problem, and I can smell the unburnt stronger than before. Anybody has the same problem????
could be the exhaust with a small hole or leak sucking air in then popping if it does when you take your foot of the throttle
I think your rally fuel might have something to do with it. It is some sort of modification. I have no experience with the TR but with my Esprit Turbo. I had a lot of back fire when I have changed the turbo. Unburnt mixture is forced in the cylinders so fast and so much that the ignition cannot burn them all. so unburnt mixture is out with exhaust gas and pop when travel to outside air. Firing system need to be readjusted..., in my case.
I am thinking that it might be running too rich, but just wonder how??? I didn't think by replacing the fuel filter (to a rally-car size) will cause the mixture to be richer. Oh...forgot one thing...I also cleaned the injectors then the back fire problem started.... So, the condition is as follow: 2 bad spark plugs, dirty fuel filters, dirty fuel injectors: NO BACK FIRE replace fuel filters with rally-type, cleaned fuel injectors: LOTS OF BACK FIRE, lots of unburnt smell. replaced 12 spark plugs: occasional back fire and still lot of unburnt smell. I think the mixture is wrong, but how does it happen??? I will bring the car in to check the mixture soon.
You mention that you had two bad plugs-did they have burn't or broken electrodes or were they fouled? Also were the two plugs on the same bank adjacent to each other? It kind of sounds like there may be a carbon build up in the cylinders where the plugs were bad. It(the carbon) is hot and causing the mixture to ignite at the incorrect time. You also mention that it seems to do this when you are going down hill or coasting with your foot off of the accelerator. This could allow some excess mixture into the cylinder and then explode after the compression stroke. ________________________________________________________________ F512M- The last of a spectacular series of vehicles and the "M" stands for MAGNIFICO!
Hmmm...the 2 bad plugs are from the same bank...right hand side...not adjacent to each other though. Is it possible that the dealer, instead of replacing the fuel filters and clean fuel injectors (for whatever reason, as i found out that both items are old and extremly dirty), they decided to play with the mixture to get the car running OK for the previous owner? So, when I change the filter and clean the injectors, the car suddenly run rich. I think I will try to bring the car in to check the mixture and the ignition timing first.
