Rough Idel and backfiring

[chico]

Hey guys need help once again. seems on going........ So I replaced the point system with an electronic ignition system and when me and my buddy finally got he car going and set the timing it ran rough, sputtering and no power. So we advanced the timing to around 8 TDC and it ran better but not great, still no power and running rough. I went back to the points and it actually ran worse, along with the rough idle and no power I was getting exhaust backfiring, funny story is that the car backfired so loud the neighbor ran out to check who was shooting shotgun in town, no lie. Anyways put the electronic ignition back in put the timing to roughly 8 TDC with 1000 RPM and the car seemed to run better till it warmed up to operational temp and got bad again. So I replaced the plugs, checked them before the backfiring and they looked fine, after when I replaced them they where black. No better, checked carb for leak, sprayed carb cleaner around carb to see if there was any difference, none. Replaced Fuel filter. So where to next.... I've noticed that the cam seals are leaking again not sure if this would have anything to do with the problem. The cap and rotor look good, do I change the plug wires? I don't know just want to park it and walk away for a season but hard to do when the cars not working right. Any help would be great thanks Rob 1978 carb electronic ignition

[124JOE]

i would time it by ear so it runs best for now,
reset the idle to 1000 or under again,then look down the carb to see if its dripping."if so back out the idle untill it stops"
then adjust the mixture srew untill it run the best it can
reset the idle again

if you been running on regular gas it may be getting cloged up
you might need a rebuild as ethenol leaves deposits
these deposits kill mowers and sow throwers
to avoid this run on priemium

[chico]

Sorry Joe that I didn't get back to you sooner, so yes I've been running premium all summer but this problem has also baffled my local mechanic. Car will start fine, will idle no problem then when it warms up to operational temp it starts to run rougher and if any amount of pressure is put on the gas pedal it will loss all power and backfire through the exhaust. Mechanic says that the fuel pressure is good and the compression test seem OK. So he is also stuck there is talk that one of the valves may not be closing or allowing excess fuel to get by or that the dizzy is just not advancing properly. I'm still at a loss and if anyone wants to chime in feel free. Thanks Rob

[So Cal Mark]

if it's running rough, you need to isolate which cylinder is causing the problem. Does your mechanic have a scope?

[chico]

I'll check with him tomorrow if he has a scope. Really weird how replacing the points has seemed to cause this problem, but like with any time I fix the car the original fix doesn't cause more problems they just seem to happen to old cars.

[majicwrench]

So it worked fine before you initially replace the points with electronic?? If so, the odds of a valve issue are nill. Your "mechanic" should be able to isolate the issue easily or he does not deserve the title. This is not rocket science.
Take a really good fresh look at your firing order. An old fashioned Ignition analyzer (scope) will show most ignition issues.
Cam seals, not your problem.
Keith

[124JOE]

you and your buddy need to read up on that carb http://www.artigue.com and the guy croft racing engines has tons of info

[chico]

So after the mechanic decided he could not help me I left the garage slowly and cautiously waiting for the next backfire. The car sputtered and coughed and went like normal . Now this is not to say it is fixed but it is good enough right now to park it and wait till next spring to address this problem. Now back to restoring the 71. Thanks for all the help
Rob