backfiring at operating temperature (1 Viewer)

[charliemeyer007]

Maybe, more likely you would need to find the whole assembly. The ones I recall were crimp sealed. I have opened crimp sealed stuff by cutting the crimp in several places and using pliers to peal it open. Fix the issue, use a sealant on both sides of the gasket, bend the tabs back into place, then hammer it closed to reform the crimping action.

This why I like the straight mechanical advance on my Delco distributor - engine rpm determines the advance. The guy who set up mine might have "tuned the weights/springs". That was like 1981 before I bought it.

 

[yomumsbum]

thanks, come to think of it i wasnt sucking air actually it felt like a tight seal. just the timing wasnt advancing or retarding like it says in my manual

 

[pb4ugo]

Sounds like the advance or retard is frozen or rusted and needs freed up. The plate the vacuum canister is connected to should pivot or rotate slightly when vacuum is applied.

 

[yomumsbum]

i think my issue is resolved it was incorrect contact gap in the dizzy thanks everyone.

 

[smokedpig]

Hello Fellas,

It's been a while since I have posted, I hope all are well. I had my FJ40 running pretty good for a while and has recently started backfiring and only runing well when the choke is cracked a bit. Assuming a vacuum leak I hooked up the gauge and it has plenty of vacuum. I attempted to adjust the fuel mixture a bit to lean it out, no luck there either. I started over, checked timing (advanced to10 degrees), and adjusted the carb using lean drop method, ensuring I maxed out the vacuum at the tail end. Right back where I started. Same symptoms.

It has an HEI Ignition upgrade, although appears to be a low quality Ebay/Amazon knockoff. One of the red ones you see everywhere. It was installed by the PO so unsure. It appears to have the plug wires that came with that unit. I have installed new plugs, carb, fuel pump, filter, and cleaned out the fuel tank and lines. Therefore I am leaning toward an ignition issue. Before dropping the cash for a a new Ignition I thought I'd check in and see what others think. I am considering a Davis HEI.

I have also noticed fouled plugs too (oily). Not all of them so it could be the old girl is just tired and needs a valve job. No smoke out the exhaust and great compression so assuming this is not an issue with rings.

Any help greatly appreciated!

 

[charliemeyer007]

Go out on a dark night open the hood and watch the plug wires while it is being started - dancing fire from the wires or dizzy could be your issue. Do a dry and then a wet compression test with marvel's mystery oil.

 

[DeskJock]

sooo ... I had your problem with a AFI system when I got my Rig earlier this year. My issue was timing. Which ultimately was a defective Dwell Angle device in the AFI distributor.

AFI is gone. Replaced the fuel injection with a CITY RACER CARB (was going to have Mark build me a carb ... ran out of dough) and a city racer Distributor.

No more back firing. Runs better too.

I did go with a Pertronix Device and removed the points and condenser ( in the glove box if needed).

Thing is .. these after market companies mean well ... but .. the quality assurance isn't like what OEM has ....