Ignition Problem...help
 

I get a babysitter and we pack a picnic lunch, a bottle of Moet and my wife and I leave the house in our 78 Vette on our way to the Concours 'Elegance Car Show in Ipswich, MA yesterday.....
We get about half a mile from the house and the car starts to sputter, then
the engine cuts out completely and I pull over to the side of the road. I
crank it over a bunch of times, but nothin' is firing.

After a bunch of experiments, it appears that I'm getting gas, but there is no spark getting to the plugs.... By now several of my neighbors have pulled over (in their Honda's & minivans) to see if I needed any help. Between telling them no and wishing I was invisible...I isolated the issue to the coil. Electric is going in, but no spark is coming out.

Today, I just finished putting in a new coil, electronic module and a pick-up coil. This is basically all the electronic components in the HEI distributor. I had to pull the distributor shaft to do it and did a real careful job. STILL not
getting any spark. What's going on?? The distributor cap, rotor and wires
& plugs were new in May and look good. The car is in a neighbor's driveway...and I don't want to wear out my welcome.

Any thoughts will be appreciated.

Re: Ignition Problem...help (bigbobbyb)
 

this sounds tough, especially when I cant see what you've done. It sounds like you've basically replaced everything in the distributer. The only things I can say to check for is make sure you have at least 11.8 volts going to the coil. HEI will not work with anything less. The other thing to check is make sure the rotor button is in place as well as the ground strap for the coil (its the metal part that lays under the coil). With that said and the new parts in there, it should run. hope this kinda helps
~Christian

Re: Ignition Problem...help (nitrocharger)
 

As already said, if you've got the 12v to the distributor and you've replaced all the components you should have covered it. Unless you got a bad part, I was sold a module that was inop once. How about the cap and rotor, did you replace those too?

Scott

Re: Ignition Problem...help (bigbobbyb)
 

The only thing I can think of is see if the rotor turns as you crank it.
:cheers:

Re: Ignition Problem...help (71coupe)
 

Check the inside of the cap carefully for a hairline crack. Also, wait till dark, then have someone crank the engine while you look for spark escaping to ground .

Let us know what the problem was.

Re: Ignition Problem...help (Rumpity Rump)
 

Thanks for all your help... Here is an update as of Noon ET today:

OK, so I go to my neighbor's house where my car has decided to reside....I get out all my tools....and for the heck of it I give the starter a spin and the car starts right up! Although it doesn't make sense, I'm pretty relieved cuz I can bring the car home. I let the car run for a few mins as I'm putting away all my tools. I open the door and I'm about to hop in the car and the engine shuts off just like I flipped a switch. No sputter or anything, just shut off. I tried to restart again, but to no avail (as I expected when I heard the way it cut out).

Sounds like a short somewhere

I checked the power at the distributor when the ignition switch is in the ON position and it registers 12V. When I turn the engine over, the power drops slightly to about 11.8V. I don't understand.... if the engine is cranking over with gusto, the coil is getting juice, the timing appears correct and it is getting gas....why won't it run?

BB

Re: Ignition Problem...help (bigbobbyb)
 

:seeya The only time this happened to me, it turned out to be the pickup coil opening when it got hot. Ohmed it out when it was cold,no problem . 10 or fifteen mins of running, car would die. Ohmed pickup coil, it was open. 4 or 5 hours later,ok again :smash: :smash: you indicated that you changed the pickup,so I quess I'd be looking for something like bad connections,ballast resistor, or resistance wire if you got one. You changed all the stuff that should cause this and still no luck. I'll be intrested to know what you finally find :yesnod: :seeya

Re: Ignition Problem...help (bigbobbyb)
 

well it definately sounds like something electrical. Is the coil new? Sometimes coils will get hot when they run and quit only to start back up when they get cold again. I'm trusting you have some silicone under that module too, right? The last thing I can think of is test to make sure your alternator is working ok. let us know what happens
~Christian

Re: Ignition Problem...help (FastGlass79-85)
 

I"ts the pickup coil, and there is NO way to change it without pulling the dist and the gear off the tip and shaft all the way out and a vice tohold it all while you clamp down the3 screws holding the pickup coil in place while you rotate that shaft /starwheel assy to check for NO rubbing...it's magnetic, NOT mechanical contact....all it does is put a pulse in the coil which triggers the main top spark coil throug the white electronic amplifier...or sending unit... some other term....

GENE :mad :mad :mad :confused: :D

Re: Ignition Problem...help (mrvette)
 

Hi. Thanks for all your replies & ideas.

This is the problem:

* *'78 Vette engine cut-out while driving and won't start * *

Observations:

- Engine is getting gas, but no spark.

- Starter turns over fine.

- Distributor cap & rotor are practically new and look fine

- Rotor is turning OK

- The "+" at the top/side of the HEI distributor shows 12V when ignition key is in ON position. Shows about 11.8V when cranking over the engine.

- Ground wire (strap) on the distributor/coil looks good and tested fine.

Replaced the following to attempt to fix:

- coil
- electronic module
- pick-up coil

Results of fixes:

- Couldn't get car to start with no spark for the first day.
- Car started first thing in the morning on second day, ran for a few mins and shut off abruptly. Have not been able to restart again (still turns over fine).

Thoughts:

- Could it be the ignition switch?
- Does a '78 have an ECM (Engine Control Module)? ...hope not...
- The only visible Ballast resistor is for the Tach

Any thoughts will be appreciated.

Thanks

Re: Ignition Problem...help (bigbobbyb)
 

Well, you'll be glad to know there's no ECM in this car. Despite the fact that you replaced the module, it could be faulty (not the first time that's happened).

Re: Ignition Problem...help (page62)
 

Folks,

Once again thanks for your replies.

This morning I got another new electronic module and installed it. The car started right up and is now running better than ever!

As some of you guessed, the 1st new electronic module that I put in was faulty. Having to assume that a certain % of the electrical parts are faulty really makes troubleshooting a PITA. Now I'll see if I can talk my friends at NAPA into taking back the faulty one.....

Thanks again!