91 Vert, 383, supercharged, automatic with an MSD 6AL ignition controller. I have an FSM but limited tool chest. I am a novice not a wrench so please play nice.

The car would not start. After looking for the obvious a friend came over and we tested for fuel pressure and spark. Found we had no spark and he doesn't know enough about ignition systems or where to check so I had it towed to my local mechanic that has kept this car running for me over the past year. I had disconnected the battery, gave it a full charge and sent it to the shop for troubleshooting. We reconnected the battery, pushed it to the bay and I gave him the keys to try and start it. Vvrooom, the sucker kicks right over. He checks the wiring by the distributor and there is one loose but not disconnected wire in one of the connectors. Since it's there, I have them do a couple of other tasks that I had planned for a later time. The alternator failed, probably because they tried to throw a charge on it and it backed up to the alternator. No big deal because they replaced the alternator in the Spring and it was still covered under the warranty. They whacked me a few bucks to change it out but not enough to complain about.
I pick up the car. It starts fine. I drive it for several days to make sure it's not going to leave me stranded sometime when I least expect it. I park it and don't drive it for the next week. I grab the keys to take it for a nice ride and I'm back to square one. No spark. I disconnected cleaned and reconnected all the wires and the connectors up by the distributor in case it was just a bad connection. No luck. The distributor was rebuilt last January. So I seek the wisdom of the gurus. Can you explain and define the ignition system to a novice from the ignition switch to the spark plug so he can get a handle on this perplexing and agrivating no start situation and put it behind him once and for all. Thanks. Tommy T.

How is the battery itself, Tommy? Sounds to me like that could be the cause of both the bad alternator and the no start. Why did you have to charge it before you sent it to the shop???

As far as the ignition system, here is a basic rundown that is explained pretty well:

http://auto.howstuffworks.com/ignition-system.htm

Matthew

For some reason I get about a dozen good start attempts before the battery loses it oomph. I think the starter pulls a lot of juice cranking over the 383. Battery is 2 years old and was starting fine when I had spark.

That's a pretty good start Matt.

YOu need to be more methodical about this.

First, take the battery out and have it load tested.

Second, get a volt meter and make sure you have power everywhere you're supposed to have power on that ignition system.

Third, check for continuity between the spark box and wherever you're supposed to have it.

Get a wiring schematic of that system and a trouble shooting guide.

Q.
It recently had the directional switch replaced. Is there anything dealing with the ignition switch that would engage the starter but prevent the spark? Like a damaged or grounded wire?

Quote:

There is no answer to that. Depends on who hooked it up and how they wired it.

It's aftermarket, it's impossible to answer.

I HATE GREMLINS


How can you test when it's intermittent? Damn it. I went out this morning and for no particular reason I jiggled the wires under the knee bolster. I shifted the automatic from park to first and back to park. I turned the key and she fired right up. So again I ask is there wiring from the ignition switch that could prevent the activation of spark yet allow the starter to turn over? Could there be a short in the wiring bundle that would prevent the ignition cycle? Could it just be the ignition switch? I think I'm getting closer to the problem now. It's tough when you go to a mechanic and tell them; It's working fine right now but sometimes it doesn't want to start. The starter turns but there is no spark. I hate trying to figure out what's broken when it's working when you drop it off. They kept it over several days last time and it started every time over three days. I'm leaning toward either the ignition switch or a short in the wires coming from the steering column.
Comments ?

Could be any kind of bad connection in the wiring harness. You have to track it down. Not fun, not easy.

Find the schematic for the ignition system, and bring it to someone who specializes in electrical problems. They can solve it in an hour, could take you weeks.

1) When it won't start, will it turn over or the starter won't engage, are there any noises, etc?

2) Did you load test the battery yet?

3) Did you try to start it before you wiggled the wires, shifted it, etc? What I'm saying there is that the wiring may have nothing to do with it, and it would have started without all that junk if it is a different issue. However, as far as the shifter goes, I believe there is a switch that prevents starting if the car is already in gear (ie, or if it's bad thinks it's in reverse). Someone will have to verify that for me. When it won't start, try putting it in neutral and starting. You'll obviously have to wait until the problem presents itself again.

Matthew

Have you checked the neutral safety switch on the transmission? It prevents the car from starting when the selector is in drive or reverse. When it goes bad it will not start at all.

Quote:

That's the switch I couldn't remember the name of. Thanks!

Battery is fine , starter is fine. Engine turns over. There is no spark to the plugs when the condition presents itself. An auto electrician is a good idea. He could unbundle test and bundle the mass of wiring under the dash. That seems like a more logical approach than a general mechanic. I just don't want to get stranded at the least opportune time. I was just trying to isolate it down a bit. Like a failing MSD or other part that could have an intermittent failure. It's always tougher to fix something when it ain't broke. (right now)

Tommy, I know you mentioned the FSM, but did you follow the troubleshooting procedure for a no-start?

Matthew

Quote:

I don't think so.

If the motor is turnin', the field output of the alternator is generatin' a load, and lookin' for a place to discharge (spark plug 'ground'), and, the charge in the battery is lookin' to dis-charge too (spark plug 'ground' (starter too)). You could even start [a] motor by hand if conditions were wrong (like when you're workin' on it).

Next time it won't start, DON'T JIGGLE. Disconnect the primary wire to the coil, and put your tongue on it as someone turns the key. Tell them to post the result of this test while you're still howlin' and fixin' your hair back. Or just use a multimeter and check for spark, unless you can see the spark.

Post back on that.

Edit: Tongue test might get them eyes sync'ed back up too! Here's a 'positive' for the test (actually negative (-))

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