Cobra cutting out

[Fordzilla]

Unless you are racing it competitively, I can't see any reason to spin it more then you are. I'd play it safe & enjoy the motor for a long time. If money isn't an issue, then let her rip!

[Blas]

Well, if you say the powers & grounds are good...both at battery and by starter....I'm thinking coil, MSD box or ignition switch.
Go to the MSD website and find the coil test information.
Simple test with a volt/Ohm meter....
You can also find the test procedure there for the MSD box, also quite easy to do. Get thru that testing first. Costs nothing but some time...Did you look at the rotor and center contact in the distributor?

[traveler]

I had something happen to mine that sounds exactely what is happening to yours . I have an MSD Ign. in mine and the Rev limiter was bad .

I dont race mine so I just removed the limiter switch and no more problems .

Rick

[rodneym]

Blas,
I checked the ditributor tonight. There was a tiny bit of scoring? on the outer magnets but O don;t think that's it. I'm going to check the MSD site and get that test procedure.
traveler,
What do you mean 'removed the rev limiter'? You mean set the limit very high? Mine is in the finned Fireball box that looks like a car stereo amp. Doesn't that control the coil when to spark or is it only the limiter?

[patrickt]

Originally Posted by rodneym

What do you mean 'removed the rev limiter'? ... Doesn't that control the coil when to spark or is it only the limiter?

He means pull the chip out of the side of the MSD unit -- that chip is the "rev limiter" and interrupts the spark at a given RPM. And yes, the MSD unit controls when the coil's field collapses to cause the spark at the plug. FWIW, the way I tackle intermittent electrical problems (assuming that's what you've got) is to hook up different colored test lights to each part of the equation and have the lights literally right in front of me (taped to the dash, sticking out from the hood, it doesn't matter). When the problem occurs, look down and see what light(s) are not working and that will give you a clue. I just did that recently for a faulty ignition switch in my Cobra that was giving me intermittent no crank situations, and seconds later, cranked up perfectly. Before hooking up my test lights, I was sure it was the solenoid (wrong), battery (wrong), starter (wrong) ... and it proved to be the ignition switch. When the car wouldn't crank the light feeding the ignition switch was on and the light feeding the solenoid from the switch was off. Jiggling the switch just right could make the light blink on and off. By any chance do you have your coil mounted horizontally? If so it needs to be the "Hi-Vibration" Coil, otherwise you can get air pockets over a winding that can cause intermittent faults. Unless you know that little trick, it's a real pain to diagnose.

[undy]

MSD ignition modules have a tendency to fail. 400 to 1300 ohms is what you should read through the pickup.

MSD has a relatively good diagnostics on their web site.

http://www.msdignition.com/page.aspx?id=3206

http://www.msdignition.com/instructi...terms=magnetic

[patrickt]

Originally Posted by undy

MSD has a relatively good diagnostics on their web site.

They do have good diagnostics. But the problem is that an intermittent fault never occurs in the comfort of your garage. Rodney, here's a "down and dirty" plan that I've used before in similar circumstances -- put a can of starter fluid in your car and the next time it dies and won't start (but cranks) quickly open the hood and pull the #8 spark plug wire and hold the tip while you reach in and turn the key and crank it. If you get a shock, put it back on the plug and see if the car will start. If it won't start, quickly remove the air filter and shoot some fluid down the primaries and crank the engine. If the engine starts and dies, then it's a fuel problem. If you were able to hold the tip of the plug wire while reaching in and cranking the engine, then it's an electrical issue for sure. If you have a pacemaker in you, have a friend do the wire-holding....

[JAM1775]

Get a $20 water filled fuel psi gauge from Summit and mount it with a tee directly on the fuel line by the carb. I would not push the motor for fear of not cutting OFF fuel but running very lean fuel. But it's always good to monitor fuel pressure. Do you have a voltmeter ? When the symptons appear connect it to your pump on/off switch. If that's good perhaps remove your ignition switch and check for 12V output there too. I once had a broken ground wire to my external electric fuel pump give me intermittant PIA problems. More seriously a few years later I had intermittent idle stalling and finally a 60mph dead stall on the highway. I did ALL the electric checks and found no reason why my fuel pressure gauge dropped from 6.5 to 1-2 instantly ...then at times back up to 6.5psi. Eventually I replaced the fuel filter, pump, regulator, blew out lines looking for obstructions. Nothing. I dropped the tank and found a loose fuel pick up baffle which could slide a bit sideways. The fuel pick up/float looked okay. I ordered a replacement tank for $100 but STILL at idle in my garage at a steady 12V with old tank at half full........2psi. Now it was not even rising. As I was swapping tanks I started to very closely inspect the fuel the pick up line. I noticed a very fine hairline CRACK on the higher portion of my fuel pick up line. BOOM. That was ghost I was chasing all along. If you have voltage drop your task is clear. If you have 12V everywhere yuo might try buying another $20 Summit fuel gauge, attach 2 tees and a foot of fuel line to each side. You could try starting backwards with psi checks at the top of the tank. Work your way forward section by section checking psi with the handheld gauge. Hope this helps.