Turbulence
New Member
I was thinking I did something bad to the head when I drilled out a bad manifold bolt....but that wasn't the issue. I'm seriously lost here.
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94 Cobra turbo build
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Turbulence
New Member
SO, common causes have been addressed. Now, uncommon causes have been addressed also. Pulled the manifold, checked all the rockers are doing their job, 125 compression across all cylinders, Ignition Control Mod must be good, cause I'm getting great spark at coil. 7 of 8 plugs throw fantastic fire, but 1 is weak. Car idles great now, but after a short time, begins to misfire on #1, always #1. I am beginning to think that the factory cobra ( I think it's an MSD dist) is bad or has a weak spot. I haven't ever heard of this before, so if anyone has an opinion, I would love to hear it.
Msd distributors are notorious for problems. You've eliminated all other possibilities so now go to oreilleys and get a rich porter remanned dizzy and see what happens.
Just to recap, have you checked injectors? Maybe tried switching that cylinders injector with another and see if it changes anything. If the injector is firing a stream instead of a mist it could cause problems. I once had a car that an injector needle was stuck open and it was just spraying a steady stream which kept the cylinder from firing and it kept washing the cylinder out with gas- wet plug.
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Just to recap, have you checked injectors? Maybe tried switching that cylinders injector with another and see if it changes anything. If the injector is firing a stream instead of a mist it could cause problems. I once had a car that an injector needle was stuck open and it was just spraying a steady stream which kept the cylinder from firing and it kept washing the cylinder out with gas- wet plug.
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ElrodKTPQ_89
Legend
May not be what's happening in your case, but I had the exact problem evil is describing twice. Cylinder 1 had good spark and had power at the injector in the harness but no fuel. Swapped two injectors around and the problem moved to number 2 injector. Replaced them and all was right again. The distributor is a good suggestion too though. I just ordered a new one from O'Reilly's like he mentioned for just under $100 and it has a lifetime warranty. Anything at all ever happens and you bring it back and get a new one, even if nothing is actually wrong but you just want the peace of mind lol.
Turbulence
New Member
Thanks you guys. I just put new 42's in, and I have tried to do what you said....but the issue stays at #1.....I even pulled the injectors, and pulsed them into a tank, very good spray pattern, quite misty in fact. Dizzy it is. I will let you know how this turns out tonight.
Is it fixed yet?!?! ;-)
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Turbulence
New Member
So....new dizzy, new coil, new plugs again. At initial start up, it runs and idles great. Like a dream even. The minute it begins to warm up to temp, the miss on #1 comes back. This is beginning to make me crazy. The heads are fine. I verified that the injectors aren't the issue by swapping # 5 to #1 and the issue stayed on number 1. I am at a loss. The next step will probably be to pull the original ECU, and see if there is a driver issue with this cylinder. I guess it could be the Electronic Spark Module, or the PCM but I would think that the issue would be more wide spread, not isolated to the #1 cylinder. Suggestions????? Please help me Obi-Wan.
Pull the ecu and open it up. There are 3 capacitors inside that like to leak out then they cause funky problems. Its not hard to do the repair if you know how to solder on boards.
Turbulence
New Member
I am a handy guy..... I shall do that NOW!! Thanks for the suggestion.
Turbulence
New Member
Nope. The ECU looks as clean and nice as the day they made the car.
Yours looks great. So if everything has been replaced in the spark circuit and the injector has been changed/swapped around. The only other things might be a wire breaking down going to the injector or maybe the ecu itself has gone bad?
ElrodKTPQ_89
Legend
It definitely could be^. Would be handy if you had a spare that you could swap and see what happens. Sucks that you're just throwing money at it and not fixing it, I've been there.
Wow...............I'm at a total loss here!!! The dizzy is really the only thing that controls spark per cylinder in the pushrods. Our ecu's don't really see each individual cylinder. Just out of curiosity have you swapped that spark plug?? If it's a bad plug it could not be firing. Best way to check and see if it's a fire or fuel issue would be to use a spark tester. Pull the plug wire off cylinder 1 and hook it up, fire the motor up and see if the tester shows adequate spark on each rotation.
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Firefighter181
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Turbulence
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I appreciate all the feedback! I have swapped plugs 3 times, different heat ranges, and every time I foul this one, I replace it. I do not trust a plug tat has been fouled. I thought that the ECU could be bad, but I am having a hard time tracking one down to swap out. I think I better do a re-wire of the injector plugs, to eliminate that as a possibility. Do you guys think that an injector could possibly "stay on" way past the duty cycle if the wiring was not good to that injector? I don't know the in's and out's of the harness, but I know that the plugs themselves are not in the best condition. I didn't want to keep throwing $$$$$$ at a problem with the same exact result. I promise I am not insane....NOT INSANE I SAY. lol, To recap, yes, Injector swapped to Cylinder 5 and issue stayed with 1. New plugs multiple times, new everything with the exception of the Spark Module ( it throws a hell of a spark so I don't see that as an issue) and the wiring harness connections to the injectors. If anyone has a lead on a Cobra ECU, or knows what I could use as a substitute without causing more issues, let me know please. I will do a little wiring and let you know what happens.
Turbulence
New Member
IS there a guide to check the electronics for voltage to see if that injector is steady dumping fuel because of bad wiring? Should I see a certain On/Off voltage or a specific resistance on the harness plug?
Turbulence
New Member
So, if you have e3ver chased down a demon like the one I have been chasing for a month now, you know that in the end, it almost always winds up being something stupid that got over looked. In my case...the culprit was the ONLY thing that I failed to closely look at during my build. Damn wiring harness was the problem from the get. I had a constant problem on cylinder 1, always a wet plug, no matter what I changed.
Here is the problem I found......badly damaged and shorting injector plug kept the injector squirting the whole time, hence the flooding.
Here is the problem I found......badly damaged and shorting injector plug kept the injector squirting the whole time, hence the flooding.
ElrodKTPQ_89
Legend
Daaaaaaaaaaaaaamn. Been there. Glad it wasn't anything major though.
So what I previously said about the injector spraying a steady stream was right, only yours was shorted out instead of the needle being stuck.
I was so damn close but still off!!!!! Lol
Glad you found it dude!!!!
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I was so damn close but still off!!!!! Lol
Glad you found it dude!!!!
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Turbulence
New Member
