dodge backfire through carb?

Question

I have '74 mild 318 with a edelbrock perf carb. When i WOT it from idle sometimes it backfires through the carb and sometimes it doesnt. It runs good,just the WOT from idle is killing it. Is the timing to advanced or retarded or ?

Also,what does the idle rpm in gear(auto tranny) sposed to be?

Answer 1

I've spent my whole life chasing problems like this--- has been everything from a carb idling off the metering rods, leaking vacuum advance ,to an exhaust lifter that can't pump up in time for wide open throttle at idle. Spend the $69.99 to make sure that everything is doing fine--then choose to fix the problem or not once you know what it is.
What Idle speed in gear means--the speed of the engine in Drive with the parking brake on (block the front wheels). No foot on the brake to use manifold vacuum, a/c and heater off, battery charged (no high alt drag).headlights off, basically no parasitic load except for the torque converter. That is how you set the idle mixture , and timing of some engines. It's also a way to tell if the engine is idling off the idle speed circuit or the Idle mixture. If you have the idle speed adjustments too high--you can have the idle mixture screws all the way in (providing no fuel) and the engine still run at idle. but it won't run or idle correctly in drive---back fires, loads down on heavy accel, ect............................ becarefull and don't rack back on the throttle--or you may drive over yourself.

Answer 2

Check the firing order adjust the timing.From past experience I've given up on the timing light.I always disconnect the vacuum advance and plug the vacuum then I turn the distributor to its fastest idle then back off just a little.Then I try turning the car over if it turns slowly back the distrubutor a little more till it turns freely.Lock down the distributor and take it for a ride if you hear a top end rattle back off a little more I find this works much better than the factory timing setting.Also I don't run the vacuum advance leave it plugged.Next with edelbrock carbs I've always found it best to purchase a strip kit and change the metering rod springs until I find the pair that works best.I've also found with edelbrock carbs that they work best on small block dodges with the choke slightly closed when warm.You also might want to experiment with jetting and metering rods a little tuning patience can pay big dividends.

Answer 3

I would suggest, that since it pops one time and not the next, that the distibutor may be at fault. I had a '70 Challenger 383 that did the same thing. Turns out it was a floating breaker plate in the distributor. The new dual point I installed, though a pain to get right, fixed the problem. The vacuum advance plate was loose..simply worn out....and caused many flaming carb moments.

Answer 4

The timing is probably too far advanced and the next cylinder to fire is firing a little early. You need to put a timing light on it. I would also check the advance when you have it hooked up. You have either mechanical advance, or vacuum advance, or both. Google the specs for your engine and see what the timing and advance should be and make sure you are in the correct ranges.

Answer 5

it sounds like a lean condition adjust the accelerator pump and see if it works if not they sell a strip kit that comes with assorted needles and jets the needles have steps replace them with the set that has the next size smaller tip
it is easy to install you don,t have to take the top off of the carb it will also help fuel mileage and power

back the timing off slightly and see if it helps

but i think it is too lean they set those carbs up on the lean side anyway

Answer 6

Thats called a lean mixture. you need to adjust the accelerator pump or richen the mixture up. But checking the timing is always a smart idea. It would be advanced if it was the problem but its not because it would do it all the time....

Answer 7

sounds like an issue with the carb. you need to find someone that is an ace at tuning that particular carb. could have the wrong accelerator pump or wrong jets.

Answer 8

Double check your firing order then adjust the timing with a timing light.

Answer 9

timing could be advanced, have you checked tach and dwell advance? let me know if you find the fix i'm a gearhead too