Still got some elusive miss. Pics

[Photonfanatic]

Well I finally got around to setting the timing on my 94 GT that I seldom work on or drive lol. Between work and school and just regular life its kind of on the back burner. But I still really want to build this car up so I still work on it when I get a chance.

So anyway, I'm looking for an elusive missfire that has always annoyed me. Setting the timing helped out a little, but its still there. You can feel the car slightly jiggle. So I took a couple pics of the dizzy cap to post up here. This corrosion on the contact points has appeared after only about 3000 miles of driving. I replaced the cap when I got the car about a year ago. Then the wife drove the car to work for a while, while her car was in the shop. I don't think that small amount of run time could build up this corrosion, but I really don't know. Also what is that weird black powdery stuff in the middle?

 

[clark98gt]

My dad has had the same problem with his msd cap. He has to replace it once a year because he doesnt drive it much and it collects moisture causing the buildup on the contacts. He called MSD about the problem and they told him to drill a small hole in it so it had a extra vent. I dont know if that will help you at all but he can atleast get a year out of a cap now.

 

[1997GT4.6]

damn I opened this bc I thought you had some dirty pics of miss2slo lol. title is misleading lol

 

[quickstang_1994]

damn I opened this bc I thought you had some dirty pics of miss2slo lol. title is misleading lol

lol

 

[clark98gt]

To be completely honest I thought the same thing lol

 

[CC'S95GT]

That's not corrosion, that's from the arch jumping from the rotor to the cap. that's completely normal.
How old is the coil?

 

[Photonfanatic]

Not sure how old the coil is. Could be pretty old i guess. What about putting a thin film of that battery terminal grease on each contact point?

 

[toyman]

Not sure how old the coil is. Could be pretty old i guess. What about putting a thin film of that battery terminal grease on each contact point?

I wouldn't do that. You don't want anything in the cap that might cause the spark to arc to an adjacent terminal. Those black speck are probably from the center contact which is carbon or was the last time I looked.

 

[CC'S95GT]

Inside the cap needs to be clean and dry.

 

[Photonfanatic]

Ok thanks for the help. But just out of curiousity, what does the age of the coil have to do with anything?

 

[CC'S95GT]

After time, the insides start to break down and you don't get the full voltage to the spark plugs. I replaced mine with a Summit brand 42,000 volt after I noticed a miss at higher RPM's.

 

[Photonfanatic]

Did that cure the miss? And do you think that there is a difference in all the coils that all the various companies sell? You got MSD, and Accel, and at least a few other performance brands selling coils for our cars. Are they really going to be any better than Motorcraft brand? Just something I always wondered.

 

[CC'S95GT]

yes, the new coil cured my high RPM miss.
I just read on the Summit site today that MSD (45,000v) is 15000v over stock. My Summit brand was 42,000v and was cheaper than the MSD.
The higher voltages are more important in highter performance applications.

 

[Photonfanatic]

So there is nothing I can do to prevent that corrosion? Do yall think that could be causing my miss? I know yall said don't, but it seems like there should be some kind of little grease or SOMETHING i could put on there...

I don't think I can afford to have my contact points gold plated lol

 

[modo]

that is not "corrosion" it is normal burn marks from the arc from the coil

if you think you have a miss start pulling the spark plug wires off one at a time while the engine is running. if you pull one and the motor does not change you have found a miss. buy a digital volt meter that does ac/dc and ohm. take ohm readings of the wires and if you find one that is way out of spec you found the problem. you can also check the primary and secondary windings of the coil that way to see if it is bad. yank the plugs and take look at them. if one of them is miss-firing it will be pretty obvious

 

[toyman]

As modo said, there are no shortcuts when diagnosing a miss. You can take nothing for granted. And say to yourself new doesn't always mean good.

 

[Photonfanatic]

Ok sounds good I will do all that stuff. I do have a volt meter. I must admit though, that I do not even know what a plug that isn't firing really feels like. About every 3-5 seconds, the car jiggles a little. And you can feel it in the seat. But the jiggle isn't always the exact same. Sometimes the jiggle lasts longer before it stops. Other times its very short. And its not always a few seconds apart. Sometimes you get 1 jiggle right after another with no time gap in between. Very frustrating.

 

[miss2slocoupe]

damn I opened this bc I thought you had some dirty pics of miss2slo lol. title is misleading lol

To be completely honest I thought the same thing lol

LOL thats funny! but yeah i could see that...

to the OP is your car a auto?

 

[Photonfanatic]

Stick

 

[v8powerv8jim]

I would check your plugs give them a clean & check gap etc,as mentioned try pulling one plug lead off at a time,if it gets noticeably worse that plug is firing ok,re-attach & try the next,but if there is no change when you pull a particular plug lead then you have found the faulty plug/lead/cylinder.