this is my last resort ... 5.0 giving me a hard time

[BlackGT89]

If you had your firing order wrong, you would have some cold cylinders and thus some corresponding cold header pipes. Run it and spray some water on each header pipe with a squirt bottle. The pipes that don't sizzle would be your dead cylinders (don't ask me how I know this... ). Edit: Did you swap cams for some reason ? That's where we ran into trouble - different firing order for HO / non-HO.

 

[BlackGT89]

I've heard they will also run if 180 degrees "out" .

 

[BarnStang]

Exactly. There will be some cold or slightly warm pipes. If it runs 180 out it would run REALLY bad. It would probably not idle without backfires and popping.

 

[turbostang79]

I put the distributor 180° out, just to see what'll happen, and it doesn't start.
It keeps popping in the carb, so I'm sure that the timing is OK.

Tomorrow I'm going to try the firing order, it doesn't seem logical that I've got that wrong, but maybe I'm just to focused on the timing issue.

I found that the previous owner put a mark on the balancer at 10° ATDC, why would any intelligent man do that ? The engine runs even worse when it's at 10° ATDC

If I would be 100% sure that after buying an MSD ignition, my problems would be gone, I wouldn't hesitate for a second. It's the knocking that occures when I connect the vacuum advance that keeps me awake at night.
Something is soo wrong with this engine

 

[stangbear427]

What ECU said- your plug gaps are too tight. Not that that's it, but it's just something to think about. You didn't happen to drop one of the plugs, did you? You could have a cylinder not firing at all if one is cracked, which you wouldn't necessarily see.

 

[dude5l]

O.K., here's my opinion. You need to pull vacuum off the carb. Pulling it off the manifold will give you the wrong advance curve on your distributor since the manifold vacuum is all but gone under WOT(you will get stronger vac. readings on the carb under WOT due to the venturi effect). Another thing you could try is replacing the vacuum advance diapghram on the dist., or try a different distributor.

 

[dastang2]

i have an accel dual points dizzy i will sell you for cheap, it may not be a duraspark but you could still use it to test things out. but i also have stock duraspark dizzys that are known to work

 

[ratrapp]

when you said you replaced the computer,did you mean the duraspark ignition box?i had a very similar problem on an old 79 cj7 with a very tough 304.i kept blaming the carb for flooding out and missfiring to find out it was duraspark ignition box that i had taken off of another good running cj.how it went bad from one vehicle to another i'll never know but that's just the joy of cars.

 

[dastang2]

that reminds me, i had a truck with the motor that is in my car now with a full duraspark ignition. one day the ignition module melted and i knew i had another one so i went home and got it and plugged it up. but the wires on the plugs were backwards. like the white wire was connected to the red. it cranked and idled but when revved it would miss badly. so i cut the wires and matched them up and it cranked and ran perfect.

 

[hllon4whls]

Here we go again with the dizzy deal. If you line up number 1 compression stroke with any spot on the cap and the rotor in the same alignment the car will run fine.

Period, end of story. So flipping the dizzy 180 without flipping the wires, she will not run.

Try this. Set the total timing at 32 degrees. Leave the vac advance off the dissy and see how she runs.

I'd also recheck the firing order VS the compression order and make sure that no wires are inductively arcing.

It might be a good IDEA to get a DUI dizzy or something similar to eliminate all of your problems.

Dont get tunnel vision. Start to narrow down the problem, but dont loose vision of the big picture!