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Discussion Starter #1
ok VMF here we go again,

First of all thanks before hand . Ok here is the issue, I have a 67 coupe with a 68 302. I have a Edelbrock performer cam with 2800 stall torque converter, AFR 185 heads Holley car, air gap intake with headers. C4 transmission. Ok here is the problem
When I am driving the car will drive ok and then after a mile or so if I pull up to a stoplight or slow down the car will cut off. It will turn over if i start it back up but then it wont start.
I had to put the car in neutral and 2 foot it, put my left foot on the brake and right foot on the gas. Keep in mind I am not good at the mechanical side yet, I thought the car was flooding because if I let it sit for a minute or so it will start back up and drive.
My mechanic was in the car today when it happened and he doesnt know what the problem is. His words were it shuts off after it warms up. He thought it was the distributor, he thought it was the Holley carb but we ran out of time to figure it out. Keep in mind if I leave the car in park it will idle forever, the idle does surge a little bit meaning it will fluctuate between 900 rpm and then drop down to say 600 then go back to 900 and go back and forth. any thoughts.
In the morning when i start it up i have to gold the accelerator down for about 2 minutes until it gets up to operating temperature. If the Rpms drop below 500 it shuts off.
Hopefully its just a simple fix. In my limited knowledge Im thinking its the holley carb, I heard they are finicky. WHat I am stuck on is the fact that it shuts off when the car is warm thats weird to me
 

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Before I'd go searching too far I'd verify whether it's a fuel issue or an ignition issue.

Got a timing light? Hook it up to the coil wire, tape the trigger down, run the light out the back of the hood and tape it to the passenger wiper arm so you can see it flash from the driver's seat. Drive. When the engine dies, if the light is still flashing as the engine is "coasting" then it's a fuel issue. If the light quits flashing at the same time you lose power, it's an ignition issue. Once you nail that down you can proceed to correctly troubleshoot whichever system is faulty.
 

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Discussion Starter #3
Ok,,, i dont have a timing light,,,, oh darn I have to go buy another tool. I will say it only shuts off while driving, it doesnt do this while idling in my garage
 

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Ok,,, i dont have a timing light,,,, oh darn I have to go buy another tool. I will say it only shuts off while driving, it doesnt do this while idling in my garage
They're handy to have, but you can probably get one from your local auto parts store's "loan-a-tool" program to use for free.
 

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Discussion Starter #6
They're handy to have, but you can probably get one from your local auto parts store's "loan-a-tool" program to use for free.
Hey I noticed in your posts from a few years back you spoke to a poster about vapor lock, is that a possible issue. This only seems to happen when the car is warm.
I dont think its an ignition issue because the car starts right back up...(but im still going to buy the timing light);););)
 

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My first thoughts were, to ensure the choke mechanism is working correctly..

Sent from my SM-G950F using Tapatalk
 

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Hey I noticed in your posts from a few years back you spoke to a poster about vapor lock, is that a possible issue. ;)
Probably not. Vapor lock is pretty much the "boiling" of fuel in the line causing a "bubble" of fuel vapor (kinda like steam to water) that blocks fuel flow. I'd expect such a disruption to cause it to quit going down the road as it starves for fuel, not coming to a stop or at idle.
 

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Verify your fuel pressure at the carb, check float settings, both very easy to do. Sounds like an overfuel issue for whatever reason. If you can keep it running when it starts to act up by fiddling with the accelerator then it is not likely ignition.
 

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I had a very similar issue to yours when I was daily driving my 67' and it turned out to be the the rear floats in my 600 CFM Holley carb being adjusted too high causing it to flood out under braking. After a bit of research I figured out how to adjust it down and its been fine ever since.
 

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Electronic ignition? That's a typical failure symptom of electronic components. As the cool down, they'll work again.

Check fuel supply. Maybe a clogged screen on the tank pick up. Or a venting issue on the tank.
 

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I had the same issue. Turned out to be the Pertronix II Ignition. Not saying you have the same but seems similar
 

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Quick test to check the ignition. When it dies and won't start, pull a spark plug and ground it away from the spark plug hole (bit of fuel may spray) while cranking and see if you have spark. If you have spark your points or electronic are "probably" ok and you can move on to fuel. Interesting comment above about the bowl floats. Can you make it happen if you try to?
 

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Discussion Starter #14
Wow, as soon as I think Im starting to get the hang of this stuff you guys come with something new. I cant make it happen per se. I can say that when I start up the carit sort of acts the same way I have to warm the car up and get it to the point where it will idle at 900rpm this is about 2 minutes.
ok i will start to investigate the carb, But ,,,,,, I still get to buy the timing light right lol
 

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Definitely sounds like part of the problem unless it is closed all the time in which case you would have other issues. Is it electric? Is it getting power? Electrics work by opening over time when a voltage is applied and then staying open while running.
 

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Actually i am certain my choke mechanism is not working correctly could that be the problem
It could be the problem. I assume your Holley has an electric choke? To verify...

- Is the choke positive wire connected to a source which has power only when the ignition is on?

- With the engine cold, remove the air cleaner and move the throttle. The choke should snap completely closed with a "CLICK!".

- Start the engine and again watch the choke. Move the throttle a few times. The choke should slowly open as the engine warms up.

- When the engine is at operating temperature, the choke should be completely open.
 

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If not sure on the choke, you can zip tie the butterfly open temporarily to be sure it is not closing. Pretty sure the Holley is simpler than the Edelbrock where you have needle valves, springs and a lot more variables. Holley is closer to a toilet with a power valve in function.
 
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