Help please - my xflow has not been running for a few months and I have just installed a new PCV valve and vacuum booster.  The car starts but now back-fires through the carby.  I am thinking that increased vacuum in the system may be advancing the distributor more than before and that I should retard the ignition to stop the back firing.  What do you Xflow gurus think?
Cheers,
Pete

Hi Pete,
 
I had the same thing happen to me when I installed a new electronic distributor a few months back. Backfiring through the carb usually means there is something majorly wrong with your timing..
 
Double check that your ignition leads are going to the right cylinders. Even if you think that it is correct, take the dizzy cap off and turn the engine over by hand to make sure the rotor button goes in the direction you think it should!! (firing order 1-2-4-3).
 
Also make sure spark is going to cylinder 1 when it should be!
 
Once you've got that sorted, if youre still not having luck you can try rotating the dizzy til the backfiring disappears.
 
Hope ive been helpful. Let us know how it goes!
 
CHeers
 
Nick

Normally backfiring through the carby is way too lean. Possible blockage in the carby circuits.

any luck?

the_cheese

any luck?

Thanks Cheese & Spiggot,
Leads are correct.  I will give it a bath in carby cleaner, then disconnect the vacuum advance and see how it runs.  If that is OK then I will re-set the timing with a timing light.  Going overseas soon, so wont make any progress for a couple of weeks.
 
Cheers,
 
Pete