Hi All, Yesterday I had the oddest of backfires when starting my 308. Occasionally the car will let out a loud pop when cranking a few times if it is a little flooded. This is normal and expected from a carb car. What happened to me yesterday was really odd. The previous day I had driven the car maybe 50km and parked it in the garage. The next morning I sit in the drivers seat and turn the key to the 'on' position to get the fuel pumps going. Note that I was NOT cranking the engine over. The instant the key makes it to the 'on' position, I hear a loud bang as raw fuel exploded in the exhaust system. The fuel pumps were not even running for a 10th of a second so I cannot imagine where a source of ignition came from. I'm not at all concerned about it but thought it strange. Any ideas as to the source or is my car just haunted?
This sounds like it could be a timing problem. When I timed my ignition for the first time, I got exactly what you describe (I was WAY out). Could your timing have slipped somehow on a bank? Check your distributors and see if they're tight, along with the rotors, etc. Ken
It could not be timing because the engine was not turning when it backfired. Furthermore, the car runs and starts perfectly well.
Seems like one plug may have sparked when you turned on the key. Even though the engine is not turning, the ignition coils get power when you turn on the key. Now, couple that with that particular cylinder had the exhaust valve open and some fuel on the plug.... Birdman
I will go with this explanation, it has happend to me with other carb cars before. Let it pass, it will probably never happen again. Mark.......
The fuel pumps were not on long enough to move any fuel so this sounds like the best explanation. I had no worries about but thought the scenerio to be a bit strange. Thanks for the feedback guys.
I thought about this too and the reason why I asked about the ignition was because we have a plug firing with the exhaust valve open. This doesn't seem right unless you have one of those simple crank trigger ignitions where the plug actually fires in response to a TDC indication and actually fires twice per combustion cycle.
Hell everyone, After researching the old posts on the forums, I have determined that I cannot quite find what I am looking for that is specific to my issue. I just set the points gap on both distributors. The car ran well and had full advance before but, it did not idle well. I reinstalled the distributors and set the timing at idle, and now the idle is fantastic, but I am not getting full advance @ 5000 rpms or above. I put a timing light on both sides and noticed that once the car gets to 5000rpm, the timing light shows serious misfiring and/or no firing at all. So I have two issues. Not getting full advance, and misfire at 5k and above. I know this is a common issue, but I am left scratching my head with this one..... thanks- john
Have you checked the condition of the point's tungsten tips for arc marks/pits/degredation before re-installing? Did you replace the condensors? Have the advance mechanisms in the distributors been lubricated/adjusted recently?
