k guys any thoughts here please. i have an 83 f-250 with the 300 in it. replaced coil, wires,plugs,cap,rotor and just rebuilt the carb yesterday. it was a first for me with tearing down a carb but i installed it and no difference in how it runs. i checked timiing and its all good as well. its like the truck is missing or something. i have noticed one thing though when i was just checking the timing it was like i was getting intermittent spark through the timing gun, the light was not flashing properly and so i put it on the other wires to see how they were functioning and some had the same problem and others ran normal(constant and steady flash of the gun) so i took the distributor out and disassembled it and cleaned throughly. it was pretty gunked up but i brought a shine back to her lol. so i put the distributor back in and it ran a little better but not much. so now im thinking either replace distributor or the duraspark box. but i wanna rule out the box cause my coil is sending lots of spark to the distributor. i am a little baffled now as you can prolly tell so your guys thoughts would really help me out here thanks p.s. i love this website i cant believe how much eveeryone helps out -but it also reminds me of how much more i can learn.

 

silly thing to ask did it run like this before you changed the plugs I've done this and must have hit the plug and the gap was off I have heard of this problem with vacume being off like the gaskets are bad try spraying carb cleaner around the carb also look for lines not hooked up as for the spark issue maybe it is time for a knew dis.scince you cleaned it it ran better hum well try these things out and let me know

blumpy

 

How do you know you have a consistent spark going from the coil to the distributor? Did you clip the timing light pickup around this wire and look at the flash, like you did when you checked each wire from the distributor output to the individual plugs?

If you did this, I don't think you can see an individual misfire. Remember, when you're looking at the flashes from the coil to the distributor, there are six times as many as there are compared to when you look at an individual plug wire. Your eyes can't detect a misfire, even at a low 750 rpm idle speed.

I had a similar problem with my '87 I6. Checked it the same way, thought everything was firing. Finally took the ignition control module (similar to your Duraspark module) into my local Auto Zone part store and they checked it for free. We found only two out of six parameters were functioning ... I was basically running on "limp-in mode". I bought a new module (about $30.00, as I recall) and no more problem. Have your local parts store check it out for you before you just replace it. Their testers are faster than your eyeballs!

Please post back as to when you find.

 

k heres the thing my car broke down and i tore the engine down and it just needed to much work and money for what it was so i decided to junk it. my roomate bought this truckbout a year ago. i guess it was blowing lots of blue so he replaced piston rings and gaskets and so on. after all that he quit working on it and it just been sitting there, so he saID i could buy it off him so i did. also when he first attained the truck he took it too a shop and got it compression testsed and got a set of new plugs. they match what the emmisions label and have only maybe 3kms on them so im guessing there good ill check gap but dont think thats what it is. anyways im going to the parts store and will get the module testsed and maybe a distributor will post again when i find out more info thanks alot guys.

 

k guys replaced distributor now. it runs a lot better but something is still wrong. when i give it gas she really shakes from 900-1500rpm then she plains out again. so i went to go set the timing and yeah i use the timing light and its a son of a bi@$h to get any flash. put the lead on coil wire and there is spark. so the only thing for the spark issue is the duraspark box thats all that i havent replaced, everything is new damn near. so anyb thoughts please. bought plugs today but still have to gap and install thatll be tomorow morning.

 

k well gapped and installed new plugs again. and yeah she seems o be all good. best its ever ran. i cant believe how dumb i was to ignore oil and black on my plugs. but yeah thanks for all the help. i took it for a little spin and it seems ok besides the fact that i screwed the exhaust so now im runnin open manifold but like i said its the best ive ever seen it run so im happy for now. talk to you all later.