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'90 F250 Rough Running

Months ago I parked my p/u & went to move it one day, it wouldn't start. After months of off/on troubleshooting and finding one thing after another, I had no spark, replaced many components in the ignition system. It finally came down to the ignition module and we have spark, but to replace the module, I had to pull the distributor. Upon replacement, it cranks over fine, but will not stay running and seems to be missing EXTREMELY bad. I have to next check all cylinders for compression, good wires for spark, etc. But is there anything that I could have done SO wrong that it runs SO rough, missing, backfiring, smells like it's flooding, etc. I appreciate the feedback and help.
 

73F100Shortbed

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I agree with Randy. You may have the timing off. Also check your firing order if you removed any wires in the process. I know it sounds too simple but two weeks ago I was doing a tuneup on my 73 and even though I removed one wire at a time I still mixed one up and caused a miss so anything is possible.
 
I agree with Randy. You may have the timing off. Also check your firing order if you removed any wires in the process. I know it sounds too simple but two weeks ago I was doing a tuneup on my 73 and even though I removed one wire at a time I still mixed one up and caused a miss so anything is possible.

smilieIagree smiliewhathesaid

Firing order is counterclockwise on the distributor and is 1-5-4-2-6-3-7-8

#1 should be marked on the cap
#1 cylinder is the front plug on the passenger side (i'm assuming you've got a v8)
If this is all correct then i think you may have the distributor off a tooth or two.
In which case you will need to refit the distributor - remove spark plugs and put your thumb over the number one spark plug hole - rotate the engine by hand until you feel a compression stroke on your thumb - now you are at or about top dead centre - look at the timing marks on the harmonic balancer (crank pulley) and you will see a mark with 0deg on it - line this up with the timing pointer sticking out from the timing chain cover , once you have done that you are at TDC - now set the distributor up so that as you slide the distributor down onto its gearset the rotor is pointing at #1 on the distributor cap - this may take a couple of tries until its right. - tighten up the distributor adjustment bolt and refit your spark plugs double checking as you go that the leads are in the right firing order.
She should just fire right up but you will need to set the timing with a timing light (don't forget to disconnect the spout connector) - std factory is 10deg on mine but you should have a sticker on the underside of your bonnet telling you what the factory specs are for your truck.

Hope this helps

Cheers Mark
 
Thanks a bunch for the info, especially from Mark regarding the rough s/u on the timing. I've triple checked the wiring, I marked everything I could when removing the distributor to replace the module, but seemed to still screw it up. I'm a satellite Communications engineer and have always tinkered with any motor I can. Rebuilding one of my jet skis right now. I've never gotten into vehicle motors cause I never had the space, but always willing to save a buck & do things myself. I'm going to give it the 'ol college try and give it a go this afternoon. Results to follow soon.
 

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