Huge misfire...

[Mercury Mike]

So I got the '65 running sweet last night. I set the warm idle, in drive, to 750 rpm with my Tach. It was running sweet. Now today I was driving over to my girlfriend's, and out of nowhere there was a HUGE misfire. It was like... the engine stalled for a second, and then went clunk, and then came back and started running again. It's been doing that and missing ever since. My plugs look pretty fouled up. I'll post pictures of them later. I made sure that all of my wiring was good, my timing is at 12*, and everything is where it should be and plug wires are in good shape. New plugs time or...?

 

[nachoman]

Two weird problems I have had in the past involved the condensor wire. The first, the condensor wire was rubbing against the side of the distributor and wore through the insulation and wore out. The second, the clip on the condensor wire was barely touching the end of the rod on the vacuum advance, and shorting out when the advance was operating.

If all of your plugs look fouled, check the distributor.

hope this helps,
kevin

 

[fordconvert]

What are the plugs fouled with? If its gas then keep after the ingition. If its something else first thing I would do is check coolant and oil for stuff that is not supposed to be there then check vac line to auto transmission for fluid (should be dry) and check power brake booster vac line( if you have power brakes) for signs of brake fluid. If thats all good get another source of good fuel and see what happens. I use a tank out of my boat but if you dont have one to borrow you can just stick new clean fuel line from the pump into a gas can. Always good to have a fire extingusher handy for tests like this. If you can get it running good like that and then hook back up to the tank and it runs like crap then you know you got bad gas. Even if you put good gas in there could have been crap floating on the top or settled to the bottom that just didnt get sucked up till the other day.

And just for people like me that read all the posts and are on several boards its easier if you post the details of what you are asking about so we/I dont have to try and remember which toys everyone else has like in this case engine, dizzy, and carb and whats stock and whats not.

 

[Mercury Mike]

It's a loadomatic dizzy (original) with an Autolite 1100 (original). C4 automatic tranny. They're black. I think I was running really rich for awhile before I learned how to really tune my carb. I got it right where it should be now I think, and I have a new set of autolite plugs and a new rotor. Thanks for your input. My modulator is new, and dry. Coolant and oil are perfect.

 

[Mercury Mike]

So anyways... I pulled the plugs again. She hadn't been running in awhile, and now that she's running again, the plugs look great. Everything that was fouled about them is now fine. I put some new platinum autolites in it, because I had them already. Anyways... I forgot to add that as well as this huge miss, she is stalling at every stop. And towards the stop, when she's slowing down, she kind of jerks forward and then stops and jerks and stops until she stalls. I'm at a loss! Any insight on that?

 

[addo]

Almost sounds like a trans issue - not downshifting as you slow up. Try slotting it into neutral as you coast to a stop. Any different?

 

[Mercury Mike]

I will try it tomorrow. It wasn't doing it yesterday, it started doing it after I raised the idle. I'm gonna take the idle back to 750 in park as opposed to in drive. I also don't have my kickdown connected right now, would that affect that in any way? My trans is a fresh rebuild so I don't think it's that. I'm thinking the idle and the vacuum at the point might be doing that. I'll see what I can get out of it tomorrow.

 

[fordconvert]

Does it have a pcv valve? Maybe some change there has messed up your tuning? Does the idle mixture screw respond correctly? You should be able to make it stall by turning it both ways and there should be a 'happy' range of at least 1 turn in the middle. If it dont respond like that there may be some passage plugged in the carb or you have a vac leak somewhere.

Remove and plug the vac line(s) from the dizzy and see what happens. Maybe there is an issue with wear in the dizzy as it moves through the advance range and the dwell is getting screwed up or there are issues with wires shorting inside like someone else mentioned. With vac advance unhooked the wires dont move. A dwell meter and a vac pump would be a handy test for this issue because you would see the meter move if there was an issue. When you had the dizzy out was there any slop in the shaft? With points it dont take much to start messing with the dwell time and the relation between spark gap and dwell can be very sensitive.

What are you running for a plug gap? '66 shop manual says BF-82 plug ( you may have wrong heat range which could cause fouling over time) and gap .032-.036. All the new plugs I have bought come gapped .045-.050 and with a stock system that large of gap is going to be a little touchey. WHen I bought mine (not running) they were gapped that wide and fouled out pretty bad, could also be because the choke was f'ed up also.

Dont overlook a fuel supply issue like contamination or a pump issue. I have spend a lot of money only to find I got tank of gas with some water in it.

 

[Mercury Mike]

Thanks. I'm gonna do a full check of everything later tonight or tomorrow.