All Small Six 1966 mustang with Bad misfire

[Elijah Gerke]

Well I have a 1966 mustang with a 1968 block and a 69 small log head and mated to a c4 auto. A couple of days ago I was driving around and had no problems, then about 4 hours later I decide to pull it into the garage because it was about to rain. When I started it sounded like it had a heavy camshaft in it(I do not have a heavy/Lopy cam) so I thought no problem probably one of the plug wires had a bad connection or my timing got knocked out, pulled timing and it was good. So i replaced plug wires because mine were a little worn, nothing still missing. I had just done spark plugs about 3 months earlier, so I thought couldn't be them, well somehow I had one bad one so i replaced it with an older one that i knew was good, still misfire after that. So i decide to do a compression test 120 on all cylinders except for cylinder 4 which had 150. So I went out and bought new spark plugs came back put them in still nothing, so I decide just to be sure i pulled timing and now after that it will not start at all and it just keeps on popping through the carb ive tried everything and I know I was on compression stroke. Eventually I got it started then it had a big backfire and would just pop through the carburetor again when trying to start, I have no idea of what to do next/what's wrong. I think that this has now surpassed my level of amateur diagnosis.
Btw when diagnosing the first time I did find a small crack in my distributor cap so I replaced it and it also did nothing for it

 

[B RON CO]

Hi, what ignition system are you running? If you have points and condenser the first thing I would do is get a new condenser. Good luck

 

[Elijah Gerke]

I am running some sort of electronic ignition from the PO

 

[drag-200stang]

My 66 was only 5 years old when the ignition switch went sporadic.

 

[bubba22349]

Just a guess but in your above post it sounds like you might of pulled the distribitor out of the engine block ("I pulled timing") Is that what you meant? If you did then the Distribitor is probably not installed in quite the right place and the timing is off quite a bit. Can you post some pictures of it. Best of luck

 

[Elijah Gerke]

When I said I pulled timing I meant I used my timing gun and checked it, UPDATE I got it started after a little bit of trial and error, sparkplugs I regapped to all .40 so I drove it and it only misses at crusing rpm If i give it full throttle it misses for about 1 sec then the missing stops and its balls to the walls for that 6 cylinder, I may be wrong but this makes me think carburation because I know with these small log heads the 1st and 6th cylinders get starved of fuel and run lean. Would cold weather cause this it went from about 60 to 20 pretty quick here?

 

[Elijah Gerke]

Well I was partially correct on the carburation aspect. There was water in the gas tank. When I asked my dad if he did anything to it because I know I didnt he said he filled it up with one of the gas tanks we have. Well it turned out that gas tank was 50 percent water and wouldnt even light. So with this knowlage the only reasonable thing to do as a 16 year old with a classic car was to do some "skilled driving" and evaporate most of the water by that, the miss was almost completly gone after that. I did end up draining the tank and put some good gas in and runs like a top.

Thank you Guys for helping me trouble shoot this problem. Hopefuly you guys get a kick out of this story. Sincerly Elijah Gerke

 

[bubba22349]

Elijah, that's a really great looking 1966 Mustang Coupe! That's too bad that you had to go through that over a batch of bad gas, but I am glad that you got it back running good again. Best of luck