Hi all,Im having a problem with my carb or ignition system.Its a edelbrock 600 cfm elec.choke, and on hard acceleration im getting a popping sound from it.When the carb pops or backfires my elky kinda stumbles like its hitting a rev limiter or somthing. Can somebody help me out?


thanks in advance
Johnnie

Problably need to adjust the timing a little, and make sure you have good wires......
If that ain't it, it may be the distributor weight and spring assembly, or vacum advance(if you have one make sure the vacum to the distributor was connected to the designated nipple on the carb and it's not getting too much vacum).

I really think it's the timing though, it's problably never had a good shot of gas like that

If you don't get it, post what year the vehicle is, motor size, add ons, original setup, and distributor type.............and are you sure the choke is working properly??????

Problably need to adjust the timing a little, and make sure you have good wires......
If that ain't it, it may be the distributor weight and spring assembly, or vacum advance(if you have one make sure the vacum to the distributor was connected to the designated nipple on the carb and it's not getting too much vacum).

I really think it's the timing though, it's problably never had a good shot of gas like that

If you don't get it, post what year the vehicle is, motor size, add ons, original setup, and distributor type.............and are you sure the choke is working properly??????
Thanks, I have a MSD HEi pro billet dist. its been in my car for about 5mos. and the carb started popping about 2 weeks ago. It could be timing,but ,cant figure out why its popping or backfiring know.My plugwires are MSD 8.5's and they have been in my car only 6mos.but they could have been damaged Ill have to check and see.

Might want to pull the valve covers off to check for proper movment of the rocker arms/valves. Popping through the carb can mean a flattened cam lobe 8O

might be time for a new cam then,maybe some vortec heads and some 1:61's maybe?

I think you have a carburetor problem. If you can accelerate smoothly at small throttle opening but hesitate on sudden acceleration then you probably have a carb related problem. A stumble and misfire can be caused by insufficient fuel enrichment with a sudden large throttle opening. The most common problem is the accelerator pump circuit. With the ignition off (don't ever look down directly into a carburetor when the engine is running if you like your eyebrows the way they are) operate the throttle. You should see two streams of gas squirting into the two primary throttle bores. They streams should start immediately as you open the throttle and reduce slowly as you reach wide open throttle. If you don't see the two streams you most likely have a worn out or broken accelerator pump cup. The other thing that could cause a similar problem is the secondaries opening too soon. On a Edelbrock this is unlikely unless you've been doing some major modifications.

How many miles are on the timing chain and timing gears? I've had high milage cars jump a tooth or two due to wear, and have gotten the same problem. It's a tough problem to find, I worked on all the above mentioned problems: carb advance, accelerator pump, timing, valves. I finially gave up and took it to a shop, they had the answer in a few minutes.

Good luck,

Elky77

thanks for the advice and replies guys, guess i will just go down the list until i find the problem.

your timing chain might not have actually jumped a tooth(yet), it may have stretched or the cam gear(possibly composite material) may be worn which would cause slack in the chain which would cause the intake valve to open too late upon high rpm's which would cause the cylinder to fire with the valve not seated which would cause a backfire or popping though the intake and carb....a good recipe for a fire :cry:

what does the vehicle do if you keep it in first gear and build up rpm's and let off the gas and allow the vehicle to rapidly decellerate and drop rpm's and cause any chain slack to reverse it's symptom?????does it backfire because the valve is now opening too early causing the cylinder to still be firing when the exhaust valve opens causing a stumle because the power "stroke" was not completed with the proper force??????does it buck or sputter or die????
or does it continue to pop through the carb????(electrical timing/advance curve spring mehanism/cam lobe(?))

if your problem is a sputter or stumble and then popping through the carb you may want to check the carb gasket or the torque on the carb bolts because a vacum stall followed by more gas than rpm's "could" cause a symptom.....

Finally, does the vehicle have a catyletic converter that may be clogged or have a melted core that would restrict the motor under high rpm's????????????????????????????????????????????? ??????????????? :o

what year vehicle and engine are we talking about anyway?

your timing chain might not have actually jumped a tooth(yet), it may have stretched or the cam gear(possibly composite material) may be worn which would cause slack in the chain which would cause the intake valve to open too late upon high rpm's which would cause the cylinder to fire with the valve not seated which would cause a backfire or popping though the intake and carb....a good recipe for a fire :cry:

what does the vehicle do if you keep it in first gear and build up rpm's and let off the gas and allow the vehicle to rapidly decellerate and drop rpm's and cause any chain slack to reverse it's symptom?????does it backfire because the valve is now opening too early causing the cylinder to still be firing when the exhaust valve opens causing a stumle because the power "stroke" was not completed with the proper force??????does it buck or sputter or die????
or does it continue to pop through the carb????(electrical timing/advance curve spring mehanism/cam lobe(?))

if your problem is a sputter or stumble and then popping through the carb you may want to check the carb gasket or the torque on the carb bolts because a vacum stall followed by more gas than rpm's "could" cause a symptom.....

Finally, does the vehicle have a catyletic converter that may be clogged or have a melted core that would restrict the motor under high rpm's????????????????????????????????????????????? ??????????????? :o

what year vehicle and engine are we talking about anyway?

WOW!! uhh,My elco is a 78 with a 350 cid sbc, the motor was in the car when i bought it 2 yrs ago. i have a edelbrock performer intake and carb (600) cfm.These were put on last year.my MSD dist.. HEI was put in 5 mos ago.. This problem started about 2 weeks ago .I noticed that at low rpm and slow accel. it would run and idle fine but at high rpm and quick accel I noticed a popping sound and hesitation like a stop and go feeling or surge if you will. But whats weard is on the freeway the car runs just fine real smooth at 75-100 mph.. just dont get it im stumped..