starting problem

73 cj5 with 258.

i pulled the original running 258 and have swapped in a 258 from a 78. duraspark. i have been messing with it for a while and i can't even get it to cough at me. the original motor is on a stand next to the jeep. today i noticed the spark was dropping off as i cranked it so i swapped the coil for the one on the old motor. the spark seems better, but by that point the battery had charged up quite a bit. it still won't cough with fuel introduced directly into the carb/intake. i have checked and double checked the timing it is close enough it should fire, and i have verified it is not 180 out. the motor ran when i pulled it out of the donor jeep. it had a water in the cylinders episode for anybody who remembers that, but it has since come free and spins easily. when it did come free there were no breaking of popping sounds that would make me think the timing chain slipped. so unless somebody has a easy fix i haven't thought of, can i pull the points distributor off of the 73 and toss it in the 78 motor just to get it running so i can drive it out of the shop?
thanks

 

Yes, you can use the points distributor. It will drop in for the Duraspark.

It's kind of hard to troubleshoot the Duraspark any way other than throwing parts at it... unless you have an oscilloscope. It has to work if you have it wired up right, and it's not broken. You can 'scope the VR signal from the distributor, and see if that makes the coil lead go high and low, just like it would with points ignition.

I suggest you go back and check your wiring to make sure you have everything connected properly. Try adding an extra ground to the black wire coming out of the module. IIRC the Duraspark module is grounded through the black lead to the distributor, so if the distributor ground is not good, the module won't work.

 

its kind of ironic that i have to have it out of the garage before i go back to school, but once i am at school i have access to two dozen high quality oscilloscopes... I will double check my wiring and and add the ground i just wired in my brand new spare coil and that didn't make a differance. but I just verified the timing and spark again. I pulled the number 1 plug and it is sparking on compression. i just don't want to get the whole ignition swapped over and have it still not do anything, not like i have a choice but... i confused why if I know timing is on, i know i have spark, and i know i dumped gas in the intake, even if my compression is bad, which i suspect it is, it should atleast cough at me or sputter or something.

i almost wonder if something is blocking the intake somehow?
Is there a easy way to check that without pulling it?

 

If the intake is blocked, your compression test will show it.

Pull your plugs and look at them. Maybe they are oil or fuel fouled. Have you tested for spark by holding the coil wire next to the block?

 

the plug are new and gapped. My compression tester doesn't work. the earliest i can get one is tomorrow night if i borrow one form my uncle

 

i pulled the manifolds off, nothing blocking them besides a bit of surface rust all through the intake from when water was in it. when i can find a flashlight i believe the next step is to check to make sure all the valves are playing nice while they are exposed. I am moving away from this being a spark issue, i have spark at the coil wire and in the plugs as far as i can tell. anybody have suggestions? it will crank, a little slower then i would like but fast enough it should do something. thanks for your help on the duraspark tim

 

well i just broke an easy out in one of the exguast manifold flange bolts... at this point i think it would be easier to go get a running jeep, cut the frame rail behind the motor mount and splice it into my frame... but i might get made fun of for that