have a 1983 dodge w150 5.2l 318cdi carter 4bbl. the problem is i have very weak spark on cylinders 3,5,6 starts runs rough at idle if you go to step on the gas it backfires through the carb have changed the plugs wires dis cap rotor coil and coil resister has had no affect on anything. it has had the same problem in the past mainly when cold or wet out but always seemed to be like "cross fire" in the cap but no marks or moisture the distributior cap but it always would go back to running normal the next day or a few hours but now is constant and getting worse cyl 3 recently started getting weak spark if you have any ideas i will try them already spent most of my money on a tune up that is worthless and im out of ideas chiltions leads me in a loop and evryone on the net seems to just scrap em after they fed up and broke.............any ideas helpful!!!!

 

how is the timing? could also make sure the ignition box has a good ground connection.

 

timing is good the advance is working too not sure on the ignition box will have to find it and take a look at it thanks

 

what do you have the timing set at?

 

16 before tdc i thinks thats what it should be its a 4 speed think the auto is 11

 

got the ignition box off ground seems to be good the only thing i seen was on the back of the box bottom right there appears to be blistering marks and soft where that is might be overheating and just worn out the parts store just closed so will be tomorrow afternoon before can get a new one

 

could try playing around with the timing and see if it makes a difference. did you unplug the vacuum advance and plug the hole when you set the timing?

 

i unpluged it to test it then pluged it back in to note the change that it was functuning properly but the timing has never been or needed ajustment ive checked it randomly cleaned ground on ignition box and the plug in no diffrence and no new one until tomorrow also removed ground and starter wires cleaned random conectors and the classic jiggle the wires to help find shorts or loose wires no luck

 

well you are suppose to disconnect the vacuum advance when setting the initial time so that vacuum advance does not effect the initial timing. all else fails play with the timing till it runs right.

 

but the problem is on cyl. 5 and 6 some times 3 there is almost no spark i have to use a screwdriver put it up the boot and hold it until there is 1/16" or less to see any arc however 1,7,2,4,8 have areat spark will jump an inch or better there is no cross jumping that is visable the new and better routed wires help ensure that i keep the best of the parts of every tune up of everything i own so when a problem occurs i can cross check and see what failed i am a GM fan but dodge over any ford worked for a dodge/ford dealership for 7 months but no one has seem to have weak spark on just a few cylinders it seems alot of newer ones have same symptoms but newer problems have a friend 27 years at the dealership and fixes them up and sells them in his own time he dont even have an idea without spending hundreds on parts to eliminate thing after thing the parts store even told me to take it to a shop they have no more tests or ideas im sorry but i liked it great pickup or was but im about to give up on it i needed it for work but now i must go back to my starter pickup 68 gmc all original except headers and carb but it has never had any problems but hope something works about broke but thanks for your ideas anything is worth a shot its just my time but thanks for your help just hope can figure out lack of spark on certain cylinders just weird to me whats in the distributer that might fail i have had a hunch to look in there but not familiar with dodge that much