Timing light stops flashing??? (1 Viewer)

[67FJ40]

Alright cruiser gurus, I think I'm closer to figuring this damn thing out but still need your help. If you have read my thread "NEED HELP" you know that I've been havin a problem with the pig back firing through the carb. It only does it when you rev it quickly. If you rev it slow it revs up great and sounds strong. Quick rev and "pop" through the carb. What I noticed tonight is that when the timing light is on it flashes like it should untill you rev it quickly. The timing light goes out at the same time the motor back fires through the carb. If you rev it slow the light speeds up with the motor. Rev it fast it goes out and "POP" then it lights back up. Sounds electrical to me. I did run a jumper wire from the battery to the positive post on the coil. No change. What else do you all think it could be. Am I on to something? Thanks for all the help in advance!!!

 

[066wally]

It sounds to me like you found the problem. You might try a new distributor cap and rotor, my guess is that it stops sending spark at the distributor as it revs higher (bad or corroded contacts). Try the same thing with other cylinders too (without paying attention to the timing) to see if the light stops flashing.

 

[fhawk5]

Let us stop and think, more gas, faster movement of engine, and faster spinning of distributor. Advance in the distributor is why performance is required. Can you try a distributor that is qualified as good? That would eliminate a lot of possible issues??

 

[67FJ40]

It sounds to me like you found the problem. You might try a new distributor cap and rotor, my guess is that it stops sending spark at the distributor as it revs higher (bad or corroded contacts). Try the same thing with other cylinders too (without paying attention to the timing) to see if the light stops flashing.

I have new cap, rotor, wires, plugs, pertronix coil/electroic ignition, carb, vacuum lines etc. I will try the other cyliders tomorrow.

 

[67FJ40]

Let us stop and think, more gas, faster movement of engine, and faster spinning of distributor. Advance in the distributor is why performance is required. Can you try a distributor that is qualified as good? That would eliminate a lot of possible issues??

I tried a new points dizzy and it ran worse and still back fired. Now, I did try it with the pertronix coil. Dont know if that matters. I also tried my old coil, but again with the pertronix electronic ignition. Ran bad. Still back fired. I havnt tried the new dizzy and the old coil together yet. Worth a shot I guess?

 

[edwjmcgrath]

I think you're onto something. If it's electrical, I'm thinking ground. When the engine revs fast, it moves a little and that might be enough to disrupt a marginal ground connection, possibly.
I would try taking your jumper cables and ground the engine to the battery neg and the engine to the frame, to eliminate bad ground as a possibility. It's easy to check.

 

[67FJ40]

It sounds to me like you found the problem. You might try a new distributor cap and rotor, my guess is that it stops sending spark at the distributor as it revs higher (bad or corroded contacts). Try the same thing with other cylinders too (without paying attention to the timing) to see if the light stops flashing.

Thanks so much for the idea to check the other cylinders! I put the timing light on all the cylinders and number 1,4,5 & 6 would stop flashing when u reved it quickly. I then replaced the NEW DENSO PLUGS with the old AC Delco plugs the PO had in there and it runs perfectly. No more back firing through the carb!!! It was the damn spark plugs! New denso spark plugs. 4 of 6 where not firing right. I cant believe it!!! It runs great now!!!!!! Purs like a kitten. Thanks a bunch!

 

[NikP]

That's good news! I would have never thought plugs would have been the problem.

Glad you were able to solve the problem.

 

[67FJ40]

Trollhole

I also want to thank Trollhole (Marshal)!!! He has helped me all along the way with my problems and has stood behind his products 100%!!!! Guys, dont hesitate to buy from this guy, he is wonderful to deal with and his carbs work great. Thanks again Marshal. Flipping bad NEW spark plugs. My luck. OH well its fixed.

 

[67FJ40]

That's good news! I would have never thought plugs would have been the problem.

Glad you were able to solve the problem.

Thanks Nik. Also thanks for the motor and trans! It was nice meeting u!

 

[akeyzoo]

I am trying to fathom how this could be the plugs.... Very interesting. Did they have screw on ends and the quick rev would cause a loss of conductivity?

Glad you got it sorted either way!

Chris

 

[67FJ40]

I am trying to fathom how this could be the plugs.... Very interesting. Did they have screw on ends and the quick rev would cause a loss of conductivity?

Glad you got it sorted either way!

Chris

I cant believe it either! I've spent well over a month trying to figure it out. They did have screw on ends but seemed to be tight. I was going to ask here on the forum how could spark plugs (new ones even) have caused these symptoms. It blows me away. I changed them one by one and checked it with the timing light. Each one I changed the timing light kept on flashing. When I got them all changed I again checked them and everything was good. Also, no more back firing through the carb (which was the symptom I was trying to correct). I have no clue. I hope someone much smarter than I can chime in on this one. Im glad its fixed but would like to understand how or why it was the plugs.

 

[67FJ40]

Anti seize

Ok mudders, this still has been bothering me. Four of six new plugs were bad. No way. What I have come up with is I think I put too much anti sieze on the plugs when I installed them and they were not grounding to the engine block correctly. I hate to admit that but I really think that was it. What do you guys think?

 

[1911]

... I think I put too much anti sieze on the plugs when I installed them and they were not grounding to the engine block correctly. I hate to admit that but I really think that was it. What do you guys think?

Personally I doubt it; the AC Delco's were in there too long and are just crappy plugs anyway IMO.

But as far as anti-seize goes, a little dab will do ya', just like Brylcreem.

 

[67FJ40]

Personally I doubt it; the AC Delco's were in there too long and are just crappy plugs anyway IMO.

But as far as anti-seize goes, a little dab will do ya', just like Brylcreem.

The plugs that were not working were the new denso plugs not the AC plugs.

 

[duffontap]

I have heard of entire boxes of new plugs failing right out of their wrappers so it must be possible.

My guess would be that you had a very weak spark that was getting extinguished by a quick flood of fuel when you slammed on the gas. Just a guess.