Engine just dies

[The73vetteman]

Out tonight in the car, stopped at three consecutive red lights and each time the engine idled at around 850 rpm as normal, then just died completely. No coughs, splutters or misfires, it just stops running. Restarted on the second crank.

Any ideas? Could it be a coil going bad?

John

 

[dburgjohn]

fuel filter or bad gas?

 

[The73vetteman]

Those were my thoughts. I cleaned out the fuel bowl (Holley 4150 carb) but the problem's been getting worse. What tends to happen is that when I back off the gas the engine dies. On occasion I get a backfire thru the carb when this happens.

I'm starting to think this is a timing problem - maybe the centrifugal advance is sticking? I'll take a look in later this week and will let you know - might help someone else in the future.

John

 

[JohnZ]

Those were my thoughts. I cleaned out the fuel bowl (Holley 4150 carb) but the problem's been getting worse. What tends to happen is that when I back off the gas the engine dies. On occasion I get a backfire thru the carb when this happens.

I'm starting to think this is a timing problem - maybe the centrifugal advance is sticking? I'll take a look in later this week and will let you know - might help someone else in the future.

John

When you take your foot off the gas, the carb goes instantly to the idle circuits; have you adjusted your idle mixture screws using a vacuum gauge? Sounds like you may have a restriction in the idle feed circuits, or your idle air bleeds are clogged.

 

[The73vetteman]

That's a good point, something else to check out.

I'll let you know.

J

 

[Rodney Gold]

You checked for vacuum leaks? As you go off the gas , vac rises dramatically and the fact you are getting a backfire indicates a lean condition.
If this was a fuel starvation problem , you would have serious problems when accelerating or at WOT.
Does the car surge at all when at steady state or do you find at steady state the car runs differently?
Check the PCV system/valve too , this can be stuck open and cause a huge vac leak.

 

[The73vetteman]

Vac leaks? Good idea - I'll take a look.

I don't think this is a fuel problem - it accelerates OK under WOT - in fact I'm leaning towards electrical. Had it running in the garage this evening - dwell is good, timing about right, 16" of Hg from the manifold, then it just stopped. Dead. No pops, bangs or whistles, just dead. And wouldn't restart.

Bad coil?

J

 

[TMPJoe]

I would check the coil too.. usually carb issues manifest themselves more gradually and all over the rpm ranges

 

[The73vetteman]

Replaced coil and condenser - problem solved!

I guess I should have been more scientific and just changed one thing at a time. As it is, I can't say definitively if it was the coil or the condenser that was at fault, but at least the motor's now running.

Thanks to everyone for their ideas!



J

 

[TMPJoe]

Replaced coil and condenser - problem solved!

I guess I should have been more scientific and just changed one thing at a time. As it is, I can't say definitively if it was the coil or the condenser that was at fault, but at least the motor's now running.

Thanks to everyone for their ideas!



J

At least somebody got their car running again!

For the money I would have put both in too and been done with it.

 

[DINO1970]

Coil and condensor

Those are classic symptoms of condensor failure. But if the coil is of indeterminant age, it doesn't hurt to change it out or upgrade. Unless your a demon about keeping it completely original, a change to a Pertronix magnetic pickup might make life easier. I've changed so many of those point/condensor sets on old chevys that the PN is permanently engraved in my memory D106P(screw connnector) and D106PS(spring connector).
Enjoy that classic.
DaGreek