At wits end

[Ron816]

New coil since day one after rebuild had aSlight hesitation upon acceleration as well as a little pop thru carb changed carb and jets still the same then took for a ride and this developed still running like crap after letting it cool down, gonna go to parts store and get a new ignition module see if that's the issue

 

[Ron816]

changed module today no change, next step is to check compression and go from there, very frustrating because I just re built the motor a few months ago and has no street miles on it, beginning to think something bad is going on.

 

[66Satellite_in_NC]

grounding problem?

 

[Yatzee]

If you are igniting fuel in the plenum that would indicate that a valve is not closing completely or your timing is way off. There are a few causes of this situation. Push rods are too long and as heat builds their getting longer and not allowing the valves to close completely. There's no guessing to rod length - you need a rod length checker and have to know the effective length ( that's the actual length from both contact surfaces of the rods weather the ends a ball, convex or a combination of both) You should be able to spin the rods even if it takes a bit of force when both valves are closed. There also exists a situation with offset crank gears ( with multiple key ways) where the wrong key way is used causing an offset in cam timing. This may not apply but it's worth consideration as it will affect the dizzy timing set point. Another thing to consider is weather the cam is partially wiped or the lifters are damaged. Those 20 minutes of break in at 2000 rpm are so critical it's little wonder people are doing the roller thing. I had a case with MSD's wires where the plug boots were severely hard to put on the plugs and had three that weren't even seated. As the air inside the boots heated it forced the boots off even more. Now I put a pinhole on the bottom of the boots to let air escape for good insertion.As heat seems to be your issue I'd look for things that expand with heat like push rods, valve stems, guide bushings (causing binding) or spring binding on the valves ( valves don't seat completely or are too slow seating). And don't discount binding within the lifter plungers caused by expansion due to heat. Either way you look at it there's some disassembly of the motor, either now or later.

 

[Ron816]

this developed soo quickly, I ran the car at idle for a little while did a couple runs up and down the street everything was running great, started on a little drive and after @ 20 minutes or so it stared a little pop thru the carb when I accelerated, by the the time I got to my destination it started running very rough like it was misfiring decided to bring it back to my garage could only drive in 1st gear feathering the throttle just to get it back, it seems like it is not running on all cylinders that's the best I can describe it, everything has been replaced on the motor. I have an inline fuel pressure gauge it's reading 7-8lbs but isn't holding steady needle is fluctuating back and forth assuming that's because I have a mechanical pump. The only thing I did prior to it running like crap was, I filled up with fuel, it's a new tank, sending unit and fuel lines.

 

[440roadrunner]

it felt like only 3 or 4, I put a timing light on each plug wire and found only 3 cylinders were firing could this be the ignition module

This sounds more like a DISTRIBUTOR problem. A bad coil or bad module could not possibly cause loss of fire on THE SAME CYLINDERS.

Check the distributor for bent shaft, loose bushings, and reluctor gap if it's a Mopar. Check carefully for rust, debri, and other junk in there. make sure the reluctor has not "turned" on the shaft. Mopar should have a pin in there to retain.

REGARDLESS I would not take anything off the table. Suspect the coil. You have a "good" old coil? You say 'everything,' "new." "NEW" does not mean "functional," especially in this chineseoated world.

If I could not find anything I would be running a compression / leak down, and INSPECTING THE VALVE GEAR

"Pulling plug wires." NEVER do this. Short them to ground instead. This is something you should do. Pull the wires / boots loose in the cap. Take a grounded probe in one hand, and insulated (fuse, etc) pullers in the other. Lift one wire at a time up and out, and stick your probe down in as you do. This will tell you for CERTAIN which cylinders are / are not firing.

Have you looked under the cap? Rotor damaged? Wouldn't that piss you off? LOL

 

[Ron816]

I have a new accel coil, new distributor,cap,rotor swapped all with original just to be sure, same problem. question I have is when I put timing light on each wire only 3 out of 8 are strobeing the others don't.

 

[Daves69]

What plug wires and plugs are you using?
Firing order verified?
Check for loose and or open electrical connections.
Check for possibility of electrical short throughout ignition circuit.
Verify proper grounding for ECU and engine.

 

[bigmanjbmopar]

I have a new accel coil, new distributor,cap,rotor swapped all with original just to be sure, same problem. question I have is when I put timing light on each wire only 3 out of 8 are strobing the others don't.

Hmm very suspicious like the reluctor in the distributor is bad. You need to pull one of the plugs that the strobe is not working on and connect it to the spark plug wire then crank it and see if it sparks to ground.

This really sounds like something is wrong with the firing. and dead cylinders to me. no strobe means no spark very simple so work backwards from the cylinder to the ignition module.


We want to help you but some of us who are not mind readers would like to know what your gear is? brand names and etc or post up some pics even better a video of the offending popping. Other than Accel coil what brand is the ignition module and what type and brand is the distributor? You may also want to keep the fuel pressure at 6 psi that Holley should be able to take 7-8 but with a mild stock build there is no reason to have it there unless your mech pump is some race pump?

 

[Ron816]

Here's what I did today changed coil no change pulled valve covers to check valve train its okay compression check 150 all cylinders I am convinced it's electrical thinking about harness from ignition module to coil and distributor must be a breakdown somewhere there how can I test to see if output from coil is good and out out from distributor? And could degraded wires from ignition module cause this problem

 

[bigmanjbmopar]

Try this, about page 9 begins a check sequence, since we don't know what parts you are running this is a basic guide on how to check for power to the distributor from the box.

http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/Ignitions/6420_instructions.pdf

 

[Ron816]

In running stock ignition module stock distributor everything's basically stock. I don't mean any respect here but none of these solutions seem to be on the right track

 

[bigmanjbmopar]

In that case read this around page 16

http://www.mymopar.com/downloads/elecignconv.pdf

 

[Hemi Rebel]

What do the plugs look like? Your test light will not strobe if there is no spark going through the wire. If the plug is so fouled that the resistance is to high, no spark will flow, and no blinky light.

 

[Ron816]

Plugs are black and wet

 

[uwss]

well, he said something ; " he stopped and filled it up with gas ". Do not discount the crap gas you might have put it in; Check your plugs, they will tell the story.

 

[Hemi Rebel]

Plugs are black and wet

Well, if it were mine i would get a fresh set of plugs in it. Change the primary jets down to a 68 or 69 and put a new power valve in and go from there. A wide band would be ideal, or even a tailpipe gas analyzer. Otherwise you will have to go by seat of the pants feel and reading spark plugs

 

[Ron816]

I appreciate the input , but think you're on the wrong track car was running fine then **** the bed something happened and happened quickly, have fuel have spark have air but runs like crap as though it's not running on all cylinders don't think it's fuel don't thinks its air but I do think it's electrical

 

[niteshift70]

Headers or manifolds? If it did it once it got hot, prolly broke down several plug wires. It would explain why it wouldn't go away once it cooled down.

 

[Ron816]

Got headers was gonna try new wires net, but the way it's running it would have to be more than a couple wires