hi all. new to the forum. been having a 79 wagon worked on. been sitting for i'm guessing 10 years or more. so far put in a reman distributor, had carb rebuilt and new coil. back fires for a while after starting. mostly if i let it sit over night, it will back fire for about 20 min then runs perfect. my mechanic buddy believes its the ignitor/ignition control module. cant seem to find one anywhere part number 429602000. wondered if anyone agrees that this may be the problem and where i might be able to find a good used or new one. thanks louis

Since the car sat, inspect all the rubber lines and hoses. Does this have a timing belt?

Given a specific time interval and the symptom, I'd say that there is an issue with the choke system. Make sure the little electric coil is connected and working, it should have 12V when the engine is running. I had a bad voltage regulator cause my 78's choke to act oddly, not far from your symptoms. Make sure it closes mostly when engine is cold and ambient temp drops, and opens as the engine warms up, probably open all the way as your temp gauge just reaches its normal warm position. 

 

 

The other option is some sort of leak that stops/get better when the engine warms up, but the choke seems most likely to me. 

Thank you for the detailed response.

i wonder if it is a head valve sticking and freeing up once warmed ?

 

fuel and oil replaced before starting after ten years ?

 

do a comp test while it is backfiring see if something reveals ?

That's what the mechanic thinks. Many have been meaning toward choke setting issues. Mechanic says that's been done. Doing some oil and fuel treatments to see if it helps. The lack of ingitioncontol modules availibile leads me to believe these aren't the issue. Thank you for you reponse

Got it going real good. Little sea foam and the valve must have unstuck.

Since the car sat, inspect all the rubber lines and hoses. Does this have a timing belt?

ea71's have timing chains and only have one cam in the block.

I thought they had gear drive cams, using a gear on the crankshaft and the one gear on the camshaft itself.

I thought they had gear drive cams, using a gear on the crankshaft and the one gear on the camshaft itself.

Yes that's correct and what i meant to say.