backfire / rough shaking acceleration - the show is tomorrow !!!!!

Anyone ?

 

Good grounds are a maintenance item that virtually all of us ignore. Clean them up. Clean your battery posts. Clean the grounds to your frame and engine. All of them related to your ignition...then report back to us, please. Also, have you checked your coil?

 

Will do ^, i have swapped the coil out

L

 

Ok lets start with basics. When running a Pertronix I believe you need to have 12 volts to it. Did you? When running points you want 12 volts to coil on crank but not during running. Need a resister. It will drop voltage between 6 and 9 volts. Make sure there is no slop in the distributor shaft ( I bought a reman from a national Tbird shop and it was junk yet still rebuilt). Make sure there is no play in the pivot on the breaker plate. My 64 Galaxie's breaker plate pivot failed on the way back from having the exhaust done and quit at stop sign. It was all I could do to get it home. I hesitated and missed all the way home.This is a common problem on Ford distributors. I have had 3 fail on me total. I now keep new one in my trunk with points and condenser. Make sure the little ground cable in the dizzy is good also. You need grounds from battery to engine and battery to fender and frame. When running spray the cap and wires with water in the dark and look for sparks. This should give you a good start. Good luck.

 

With a test light I got 12V at the + coil, i got a flash on the - side while cranking.

Disconnected all my accessories at the switch and the battery. checked my ground strap from the firewall to the intake, cleaned it and made sure i had a solid connection, Checked all my connections, connectors on solenoid were loose. Ignition switch nut was a lil loose. She started up and ran for about 20 seconds, . . . . . . . tried again and i got nothing, not even a click. Gonna swap out my Solenoid.

L

 

I had a miss sized voltage regulator that caused the voltage to drop below the minimum required by the Pertronix. The engine would miss until higher rpms. Make sure the voltage never drops below the amount indicated in the manual.

 

Test lights do not measure voltage and will often work at lower voltages ,Have you done a compression test,have you checked for vacuum leaks?

 

Put your timing light back on and check for timing wander at higher rpms. A high idle (with no load) at around 2500 rpm will either show moderate wander (timing chain) or it will be fairly rock solid.

 

A light tug on a wire will reveal if the internal copper strands are broken.

Pull lightly on the wire were you think that the wire is broken. The rubber coating will stretch if the internal copper strands are broken.


jmho


moe



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Also,

A vacuum gauge is one of the most valuable tools you will ever own (and I do mean that)....

A good vacuum gauge will help you diagnose many internal engine, ignition, valve and carburetor problems.

It will also help take the guess work out of diagnosing stubborn engine related problems rather than just throwing parts and money at it.

Along with your vacuum gauge you will need this chart.

Pay particular attention to the needles movement ...
Is the needle wandering slowly? popping up? pulling down?
Does the action of the needle correspond with the engine rpms (does the needle repeat the action in time with the rpms)? or does the needle move independent of the rpms (does not really correspond to engine idle or rpm speed)?





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The vacuum gauge i have is broken, i have been meaning to get one on there, but each time it has been running i haven't had one around, i will pick one up this week.

After i changed out the pertronix to another unit the timing mark stopped jumping.

L

 

backfire will blow a power valve if you run a holley carb, that will make it run bad

 

get it fixed yet? I went through this same problem with pertronix. It wasnt the pertronix itself it was a bad ballast resistor!.....it ran like **** till it sped up to higher rpms...i done everything to fix it till i read somewhere that the pertronix module needs full 12 volts to work...pulled that ballast resistor and its been running great ever since.

 

Rewired the car in 06 with a Ez wire kit.

Just replaced the solenoid and added a 4gauge ground from the block to the frame.

Car started up - ran rough as hell - then died and wouldn't start again, . . . . gonna get another coil and try it

L

 

This is a really outside suggestion but it's worth a shot. I had VERY similar problems with my 383 Chrysler. I thought it was a fuel problem, rebuilt the carb, same ****. Thought it was a vacuum leak, pulled the intake off and sealed it 3 times, still same ****. Thought it was a bad cam, replaced the cam and timing chain, same ****.

Turns out my harmonic balancer had spun about 30 degrees. So when I was setting my initial timing thinking I was 4 degrees advanced, it was 25 degrees retarded. It ran, barely. Would idle pretty steady, but as soon as i'd start to drive it would run rough and back fire on occasion. I pulled the #1 plug, stuck a screw driver in the hole, and manually turned the motor over with a breaker bar until I felt the piston reach the top of it's travel. Then I used a silver Sharpie to remark the balancer. I set the timing from that mark, and it has run like a top since.

I know it's an off chance, but it's worth looking at and won't cost anything to fix. Good luck

 

Joe - i will double check my no.1 TDC again, i did the screwdriver also.

Oh . . . . . . . . and i flipped the dizzy 180 and checked that too,....... backfired like a mother****er,........ so im right on there

L

 

OK. once again shooting in the dark, everyone has had the same ideas I was thinking, But I will mention this one because the way it is running is the same way an engine will run if the fuel has water in it, I know because living in the east, there is a lot of water in are fuel in the winter time, will only take a min. to elimante this one, take a clear bottle and take a fuel sample, you will see the water seperate if it's in there... I have ran a pertronix for a long time and have never been left walking, make sure you have the right Ohm coil, If I remember right they are sensitive to that one... Good Luck

 

great you found the problem ,hope it was in time to make the show,,one otherr thing that can cause these problems ,,,,a hairline crack between the plug wire terminals in the distribut0r cap,, and another old school trick is to park the car where when the sun goes down it will be completely dark, then start is up and look under the hood for spark traveling to a ground,,,

 

soooooooooo..........

I changed out the Solenoid, i pulled the ignition switch in the weekend,. i forgot i had the switch on ACC and had not disconnected the battery,so, . . . . . . . . at 1am Kristin is like "what the **** was that" !!!!!!!!. I go outside and see the Galaxie smoking like a ma****a, oil everywhere, thought the car was gonna burn down. The ignition lead had heated the coil till it exploded everywhere:



I went out there this morning and swapped out the coil, cleaned up aprons and finished installing the ignition switch.

I pumped the pedal 4 times and thought "**** it, lets see what i get" . . . . . . . . all the time getting ready to do a compression test to find out i got 1 dead cylinder.

Cranked her over and BAM !!!!!! she started running, smooth like michael jackson before thriller. . . . . . . . warmed her up to running temp and played with the timing, idle and fuel mix. Let her run for 25mins and she sounded great.

So im not sure if it was the coil, the solenoid or the IGN switch, I have a feeling it was a combo fried rice deal on it.

HAPPY THANKSGIVING !!!!!!

 

I had a coil blow before also. We happened to be there with no shirts on. Hot tar everywhere. Did you have in ACC or IGN position. If key is to the left (acc) there should not be any power to the coil. I dont thinked I have tried mine in that position but I know my 68 has a left (acc) position.