Back fire

[singapore stag]

Hi, Fellow owners of beautiful unreliable attention seeking Sports cars,

I had a slight back fire, not too loud .....about 3weeks ago, prior to that it was running ok, I have started the car after 2 weeks I now have a constant back fire sounds like a small fire cracker going off.
The HT leads are new, the Spark plugs are new so is the Bosch red coil, new electronic ignition.
Your expertise will be much appreciated as to what the problem may be. The car has not been on the road as yet, just start it up in the garage now and then.

[73 Mimosa]

Never disregard something being a problem just because it's new.

[SaphireSpud]

If happening at tickover, sounds like ignition timing, if driving and on the overrun sounds like play in the valve guides. Regards, John.

[DZP]

Hi,
Could be an exhaust valve sticking open or broken valve spring, particularly after a period when not used.
Try removing each plug lead in turn and see if the backfiring stops.
Den

[Phil S]

It unburnt fuel burning in the exhaust, valve sticking open, running on choke too long, retarded ignition timing could bo one of several things or a combination

[flying farmer]

Check you have the plug leads on in the correct order, its not always obvious its running on 6 cylinders if the missfiring ones are evenly spaced, but it will backfire like a good un. BTDT

[trunt]

Check you have the plug leads on in the correct order, its not always obvious its running on 6 cylinders if the missfiring ones are evenly spaced, but it will backfire like a good un. BTDT

haha..Of course! Yes.. Been there..

[singapore stag]

Check you have the plug leads on in the correct order, its not always obvious its running on 6 cylinders if the missfiring ones are evenly spaced, but it will backfire like a good un. BTDT

The plug leads are ok, it was running nicely until now. I will start to investigate tomorrow.........where would you start first?