Can't Time It - Take Two

[Patrick H.]

Hi,

A follow up as of today:

I replaced the condenser with a known good one, and disconnected the capacitor on the side of the coil. I verified that the coil is wired correctly and that TDC is really TDC, and that my distributor is aiming nearly right on target. I also checked the voltage at the coil - 5.5v, which isn't bad for this battery. My other car gets 6.5v with a better (used more often and therefore recharged) battery, so that isn't bad. I then checked for continuity, and there's continuity between the Negative post of the coil and pretty much anything on the distributor.

Still runs like it's on 6 cylinders and gives off a fuel smell (due to unburned gas). I didn't have time to play with a timing light.

Any new thoughts? The next thing is to once again verify spark plug wire placement (third time) and if all that fails, see if I can find another distributor to swap in. I'm out of town next week, so I hope to try before then.

Thanks for all the hints and suggestions thus far. More suggestions always appreciated.

Patrick

[G B.]

Sure sounds like low voltage at the coil.

When your car is running, the alternator is putting out around 13 volts. That would give you maybe 8-9 volts downstream of the ballast resister to the coil.

You can check for this problem real quick by jumping the coil off the battery and firing the engine. Contrary to all the posts which will most surely follow this one, your points won't go up in smoke. You can run for thousands of miles without a ballast resister. I've done it, and I've not yet been damned to eternal hellfire.

[Jack H.]

Re: Sure sounds like low voltage at the coil.

Agree with Jerry's analysis/suggestion EXCEPT [caveat] Shark cars of this era don't have a discrete ballast resistor-the function is built into the engine wiring harness....

[Patrick H.]

Re: Sure sounds like low voltage at the coil.

Agreed, Jack. It's a built-in piece of resistance wire.

One additional piece of info: the voltage in each car was measured "at rest." Neither was running, and I'd assume that the voltage in that case would be less than with a running, and therefore charging, car. Remember, I can't get the car to run long enough to check the voltage...and the car in question has been starting the motor a lot and not getting much charge in return. I'm going to put the charger on it next time I'm there.

So if the voltage at the coil IS low, how does one fix THAT, pray tell? I'm afraid I'm not going to like the answer.

Patrick

[Gary S.]

Re: Sure sounds like low voltage at the coil.

The others have given you far better information than I can but I have had two cars, one GM, the other not, with coils that exhibited partial failure at random times. Since coils heat up during the course of opertion, is it possible that you have an internal failure generated by heat that is only intermittant. Swap out with a known good coil?
Gary

[Patrick H.]

Re: Sure sounds like low voltage at the coil.

That was done previously. No help by changing coils.

[ROB DAME MEM# 36211]

Re: Sure sounds like low voltage at the coil.

If it's loading up you could have fouled plugs also check
the dist. ground by running a jumper wire from a good ground
to the distributor. just a thought Rob

[Phil Fischer]

Re: Can't Time It - Take Two

I have been following your posting, and I must add my two cents worth. I had a similar problem trying to time my 61'. I couldn't get the timing light to "fire" on the number one cyclinder. I thougth the light was bad, so I bought a new one. I found that the number one plug, although fairly new, was fouled out, and not firing at all. I then checked and found two more fouled plugs. I replaced all eight plugs, hooked up the timing light, and it worked perfectly. I had tuned the engine a short time before, and did not think the any of the plugs could be bad, but that was the problem.

[Patrick H.]

Re: Can't Time It - Take Two

Phil,

I've already taken them all out and cleaned them. Other than being wet from gas, I couldn't find anything.

I'm actually considering replacing them all anyway if my condition doesn't improve by hooking up a full 12v to the coil as a test. I've seen a broken plug that missed, and the thought has come to mind. The car has zero road time, so the odds of this are low, but to date nothing else has worked either.

Patrick

[Roy Braatz]

Re: Can't Time It - Take Two

sounds like cross firing in your Dist CAP or rotor Try a new one or other cap and rotor first.You may have a crack in the Dist CAP or rotor!

[Erv Schlepp]

Re: Can't Time It - Take Two

You continue to focus on the fact you can not time the car, yet you state it will not run long enough to time or trouble shoot. If this were my Corvette I would arrange to get the car to a shop that has an engine analyzer and find out what is going on with the ignition system. Spark voltages, timing, dwell, coil output etc. can all be monitored in real time and if its a ignition issue it will show up. Sounds like you have tried the prevebial blind exchanging of parts, guessing and talking to anyone with an idea long enough to realize its time for acquiring actual measurement of the ignition parameters while experiencing the problem. I am confident that a shop in your location will still have an engine analyzer, such as a Sun or other to assist you.

Good Luck and let us know what the culprit turns out to be.

[Patrick H.]

Re: Can't Time It - Take Two

Erv,

You're welcome to come on over and trailer the car to the shop and then pay for the diagnostics by some guy who just failed high school shop class. As that's not in my program or schedule or desires, I'm going to keep plugging away at it. I fail to see a reason why I can't figure this one out in my own garage.

Or I'll just sell it.

Patrick