318 chugging and backfiring

[mikeyb0013]

OK guys I need some advice. I had to redo my intake manifold as it was leaking after doing the 4 barrell conversion. I got it all back together and started it. It went to high idle and as soon as i touched the gas it stopped. Now it cranks and sometimes catches but seems to be running on 3 cylinders. I have to feather the peddle to keep it going and it eventually stalls and backfires through the carb. I reset the timing to TDC, replaced the ballast, electronic ignition, distributor cap and tested the coil. Still the same result. Any ideas?

Appeciate the input and suggestions.

Thanks

Mike

 

[memike]

Are you sure that you have the distributor rotor pointing to # 1 when your #1 piston is all the way up in compression stoke It could be you are 180 degrees out of time and sounds like it to.

 

[mikeyb0013]

Are you sure that you have the distributor rotor pointing to # 1 when your #1 piston is all the way up in compression stoke It could be you are 180 degrees out of time and sounds like it to.

Yes we pulled the plugs and i stuck my finger in #1 while my son cranked it with a socket. Once I felt the pressure coming up we set it to TDC and the rotor was dead on #1. It does sound like it's 180 out though, although it ran the first time and just shut down. Thanks for the post.

 

[memike]

What carb and intake are you using together, You could have a bad vacuum leak there, If you can keep it running spay WD=40 around the base of the carb and see if it sucks it in and it will go to a higher rpm, The carb may not be mactching your gasket to your intake, Sounds like you have a bad vacuum leak, Look real close at anything you changed or moved , Do you have power brake's? The vacuum supply to your booster needs to be looked at for leaks too.

Hope this helps, You may want to check for vacume leaks around your intake too.

 

[mikeyb0013]

What carb and intake are you using together, You could have a bad vacuum leak there, If you can keep it running spay WD=40 around the base of the carb and see if it sucks it in and it will go to a higher rpm, The carb may not be mactching your gasket to your intake, Sounds like you have a bad vacuum leak, Look real close at anything you changed or moved , Do you have power brake's? The vacuum supply to your booster needs to be looked at for leaks too.

Hope this helps, You may want to check for vacume leaks around your intake too.

It's an Edelbrock 1406 with an Edelbrock intake. I'll try that. Just looking at it I have a spare light brown wire that comes from the harness. One of them goes to the coil the other is a male end hanging. I'll pull the coil off and see if there is a missing connection. I can't see anything on the block on the firewall for it. As for the brakes, yes they are power. One hose (new) goes to the manifold and two of the inlets are capped.

 

[Badart]

Do you have a timing light that you can advance? If so check your timing. You don't want to run at TDC because it will run like poo. Advance your timing so you can eliminate that as the problem. Did it run fine before the intake and carb swap?

 

[doktor_x]

Triple-check the firing order.

 

[mikeyb0013]

Do you have a timing light that you can advance? If so check your timing. You don't want to run at TDC because it will run like poo. Advance your timing so you can eliminate that as the problem. Did it run fine before the intake and carb swap?

Yes it ran fine before the swap, one of those why did I do this things!! I do have a timing light with advance. I'll check the firing order again, advance the timing and see what that does and post the results.

Thanks for the posts.

 

[mikeyb0013]

Yes it ran fine before the swap, one of those why did I do this things!! I do have a timing light with advance. I'll check the firing order again, advance the timing and see what that does and post the results.

Thanks for the posts.

Well I got her going but the strangest thing is I timed it, advanced the timing shut her down and two days later when I went to start her the timing was off. WTF?????

 

[demon seed]

Well I got her going but the strangest thing is I timed it, advanced the timing shut her down and two days later when I went to start her the timing was off. WTF?????

If the timing is off again it's probably one of 4 things, the outer ring on the crank balancer is loose and your timing marks are moving or you didn't tighten down the distributor last time :toothy10: or the rotor is loose and shifting on top of the distributor shaft or the timing chain has jumped 1 or more teeth on the cam gear. The rotors easy to check just try to turn it on the shaft keeping in mind that it will look like it's turning in one direction cuss you're actually opening the flyweights on the centrifugal advance. It should not turn at all if you go in the opposite direction.
Two ways to check the timing chain is with a socket and rachet on the end of the crank bolt. Turn the engine in one direction till you see the dizzy rotor move then turn the crank in the opposite direction till you see movement. The difference between the 2 should only be a 3-5 degrees. It'll be a ton if the chain is so stretched that it jumped a tooth.
The other way is to remove the fuel pump, turn the engine over in the normal direction of rotation, with rachet and socket, then go in the hole with your index finger (disconnect battery before this step) and just around the corner you'll feel the chain and be able to check the slack. Even though you'll be on the slack side of the chain there only should be about 1/4". Again if the chain is shot there will be a ton of slack. I had a chain jump on a 340 year ago and it barely started the next morning and idled like a pig and belched and farted through the carb.

Terry

 

[slantscamp]

do you have the plastic gear on the ditributor still or a bronze one. we had a plastic one break. we changed the timing chain and it still wouldnt run. finally pulled the dizzy out and most the teeth were broken off the plastic gear. lesson learned. i would check that first since its the easiest.

 

[mikeyb0013]

Thanks guys,

It turned out to be a simple stripped tie down bolt for the distributor. It felt tight when I put her in and so did the distributor if I gently tried to move it. But as the car ran it just started to slide. Replaced the bolt and presto we're in business. She runs like a top now.