1967 GTO w/455 ci engine just dies

[GTO-1967]

Hi folks.  I'm Mike McNew.  I purchased a Resto-mod '67 GTO last year with a 455 ci engine, Holley 4150 four barrel and HEI Flame Thrower Distributor with 4200 miles.  The Restoration was finished in 2011.  Ran great for this past year then developed an irritable personality trait that has me baffled.  .

Here's the scoop:

Over the past month:

-  The car cold starts fine

-  Then I've run into the following scenarios where the engine just dies

    1.  The first time it happened was about 3 miles from the house.  Cruising along at 50 mph the engine just stopped (tack down to zero) and bucked one or two times trying to restart in gear, then died again.  Once I pulled over it restarted and ran fine for the rest of the run.

    2.  The next time it died happened about two miles from the house at a traffic light.  Again, I pulled over and it restarted and ran fine.  Then it ran fine for the next two times out.

    3.  On another day, I backed it out in the driveway to let it idle to warm up and it died.  I thought I had gotten a bad load of fuel, so I dropped the fuel tank, drained it completely and dried it out, replaced the carb filters and refueled with fresh gas.  I did not replace the fuel filter on the Summit Fuel Pressure Gauge mechanism as it looked fine.  It ran fine for the next two or three times out.

    4.  Then on a subsequent outing, it died at a stop sign at the end of my street.  It restarted and died about 50 feet further.  Hard to restart but finally got it back home.

    5.  Next time out it ran fine

    6.  Then today, I was heading to Mckees37 Car and Coffee.  It started fine but died as I was backing it out of the driveway.  It cranked and cranked but wouldn't restart until I sprayed a bit of starting fluid in the Holley.  

Now it's sitting in the garage just irritating the hell out of me.  The one thing I did notice this last time is that when it died and before I touched the ignition, the radio was still playing so there was some power.  I’ve also giggled all the wires I can find while the car is idling to see it there might be a short or loose connection but so far have been unable to make the engine die.  Don't know if any of this is helpful but thought you should know.

So, it's got me.  Does anyone have any ideas?   

[dualquadpete]

HEI distributors {stock] have a problem of the wires from reluctor pick up partially breaking and cause intermittent ignition failure, your "flamethrower" might have the same problem. advance mechanism tugs on these "tiny wires " and eventually break enough to give ign. stop & go problems??

[Fitzy]

I hope this helps, but if the car dies flat with no jerking or bunnyhopping, sounds like electrical. If it stumbles and carries on, more than likely fuel. I can only suggest that a methodical approach starting with the entire fuel system, and then the electrics. So, the line from the tank, the pump, filter, carby. Fuel is normally the easy one to sort out. I know you cleaned the tank out, but a bit of crud that gets sucked up, engine dies, crud falls off, engine starts and so on. I wish you well!

[GTO-1967]

Thanks Fitzy.  I'm thinking given the fact that since the engine stops immediately and completely your thought about the issue being electronic makes great sense.  I've heard that my HEI Distributor might be a good place to focus attention.  I'll let you know what Gremlin is causing this problem once I nail it down. 

[GTO-1967]

16 hours ago, dualquadpete said:

HEI distributors {stock] have a problem of the wires from reluctor pick up partially breaking and cause intermittent ignition failure, your "flamethrower" might have the same problem. advance mechanism tugs on these "tiny wires " and eventually break enough to give ign. stop & go problems??

Thanks Pete.  Sounds like a great place to start.  

[JUSTA6]

Call Jeg's or Summit and speak to the tech guru.  They are very knowledgeable, tell em you think it might be probs with the Distributor.  See what they say.  Or just call Distr. manufacturer directly and talk with the tech.  For it to shut off without sputtering does lean to electrical.  Gunk in the fuel bowl can plug a jet JUSTAS quickly or a bad seal on the accelerator pump. (that doesn't explain shutoff @ 50mph.)  Take the top off the carb,  lookin for gunk in bowl, sticking float needle or rubber on end of tip,  check gas level in bowl,  accelerator pump seal,  Any one Could be runnin ya out of gas. I'm taking the cruise route less traveled because you mention using starting fluid to make it run last time, pointing to fuel system.  Mechanical or electric fuel pump?

[Frosty]

I support everything everyone has said above. While I think this is a low possibility, it's worth inspecting. Vapor lock. Do any of the fuel lines ever get close to the exhaust at all? My concern is the fuel is vaporizing in the fuel line before the carb, close to some heat source like the muffler, header or exhaust manifold. Once the car shuts and the fuel cools slightly is can flow again.

Fixing vapor lock means removing the heat source (insulation, re-routing the lines) or increasing the fuel pressure (usually an external fuel pump).

[dualquadpete]

Frosty, vapour lock would have symptoms of sputtering [ running out of gas] by description this is "just shutting off" !!!  Would be nice to know when it happens if it's got spark before it decides to start again !!!!  Could also be a bad coil in HEI cap???

[Frosty]

I agree Pete. Just wanted to remove that as possibility or contributing factor. Electrical is the most likely gremlin here for my money too.

[Last Indian]

Electrical is a good possibility, but my first reaction is carb. I love Hollies, but they a very temperamental carbs. In particular floats and power valves. And no, more often than not they don’t spit and spotter they just die. If it’s carb I would bet sticky float! Fuel bowls full, car starts fine, float hangs up carb runs out of fuel. Car sits a minute, float falls down because fuel is gone and residual pressure is pushing on the needle, bowl fills and it runs ok till the next hiccup.

[64 kiwi boni]

2 hours ago, Last Indian said:

Electrical is a good possibility, but my first reaction is carb. I love Hollies, but they a very temperamental carbs. In particular floats and power valves. And no, more often than not they don’t spit and spotter they just die. If it’s carb I would bet sticky float! Fuel bowls full, car starts fine, float hangs up carb runs out of fuel. Car sits a minute, float falls down because fuel is gone and residual pressure is pushing on the needle, bowl fills and it runs ok till the next hiccup.

i agree with Last indian, sticky needle on the primary bowl should be a possible culprit. and also daulquadpete's comment about the hei over heating and shutting off,,,, or a broken wire to the dissy ! 

[GTO-1967]

Finally diagnosed the total ignition failure as the HEI Distributor.  My mechanic ordered and replaced the internal parts and things run great.  Thank you all for the suggestions.

[64 kiwi boni]

good job Mike 

Edited April 29, 2022 by 64 kiwi boni

[JUSTA6]

53 minutes ago, GTO-1967 said:

Finally diagnosed the total ignition failure as the HEI Distributor.  My mechanic ordered and replaced the internal parts and things run great.  Thank you all for the suggestions.

Glad you have it figured out. Time for some fun this summer!  Post up some pic's of cruise nights N shows you attend.

[Fitzy]

I can't believe it -  I was right about something.

It is so satisfying to sort a problem that's been giving you the shits for weeks, especially a sneaky one like a faulty dizzy - very hard (almost impossible) to diagnose. You should teach the car a lesson by laying rubber up & down the street. 

[64 kiwi boni]

2 hours ago, Fitzy said:

I can't believe it -  I was right about something.

It is so satisfying to sort a problem that's been giving you the shits for weeks, especially a sneaky one like a faulty dizzy - very hard (almost impossible) to diagnose. You should teach the car a lesson by laying rubber up & down the street. 

i am with Fitzy! do us a burn out 

[GTO-1967]

Yes, you nailed it!  What I did to narrow down the possible issue was to tap into the 12 volt lead to the distributor (dizzy to you) and run a wire into the car's interior with a light at the end.  I wanted to know if the 'dizzy' was still getting power when the ignition failed.  The next time the engine crapped out, the light stayed lit confirming that I was still getting power to the distributer.  So next, I pulled a plug wire and found I wasn't getting any spark when cranking the engine.  Blimey,  the problem was in the HEI dizzy.  Didn't bother to figure out which internal part was the culprit, just replaced them all.  

 

 

[dualquadpete]

Glad to be of help, that’s why I thought it was a HEI problem from past experiences with those tiny wires breaking from relluctor pickup and engine just shutting off. Enjoy your ride!