Warm engine stalling

Fishfan

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I posted about this before but haven't been able to resolve it. Here's the situation. Car cold-starts perfectly. I drive it for a while and after about 30 mins I'll pull up to a stop sign or red light and it will stall. Engine temperature is not HOT but warm, normal. Restarting is difficult and often it will stall again when I shift in drive. The only solution so far is to let car sit for an extended period of time, like 30 minutes.

This has been ongoing since I swapped my intake manifold to accommodate my new 4-barrel Edelbrock 1406 carburetor.

What I've done so far:

• Disconnected my brake booster from the carb and plugged the port on the carb. I have a new booster on order because the existing one was causing the idle to drop when brake was applied, so I suspect the diaphragm inside is shot. Car is driveable without the booster (didn't come from the factory with a booster and I drove it that way for 13 years). I thought maybe the vacuum leak was causing my stalling problems.

• Plugged the vacuum port on the intake manifold that was connected to the AC controls, trying to eliminate any potential vacuum loss.

• Also, I disconnected my PCV valve from the valve cover and carb. Put a breather on the valve cover and a plug on the carb. Again, trying to eliminate any places of potential vacuum leak.

• Leaned out my idle adjustment because I thought maybe it was running too rich for warm operation.

None of the above has worked, so what can be causing my stalling?

I saw a suggestion for a similar problem on another forum for a different make of car that the carburetor float heights might be off. Now this is a brand new carb, so I'd like to think it came with the proper float adjustments from the factory but who knows? I guess I have to get in there and take it apart and see. Or perhaps the factory specs don't work well with my set-up? If so, what should I be looking for?

What other causes can we attribute my warm engine stalling to?
 

Sixpactogo

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It sounds electrical to me. If you have electronic ignition it could be your ignition module heating up. The biggest cause of that is a poor ground. You can check it with a digital Ohm meter. If you have more than a .5 ohm reading between the CPU case and Neg post on your battery, it is probably causing your problem. What happens when not properly grounded, the current flow will heat up the transistor in the CPU and it will open the circuit until it cools down. Not always the problem but it seems to be very common. It also heats up the coil so it is too hot to touch. That is where I would start.
 

Big_John

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What other causes can we attribute my warm engine stalling to?
You haven't said anything about how the choke is adjusted. A choke that comes off too early or too late can cause this.

There's also the fuel pump/pump rod to think about. Most guys just won't do the simple task of checking fuel pump volume with a soda bottle and a rubber hose, but I always suggest it anyway... Fuel pump pressure can be checked with a pressure gauge (like the Harbor Fright kit for example) that's not a lot of money.

Car is driveable without the booster (didn't come from the factory with a booster and I drove it that way for 13 years)
This statement kind of bothers me.... Never saw a power brake car that could be driven safely without power brakes. Yea, it stops, but you really have to stand on the pedal. Did you use the correct pedal linkage? The power brake linkage has less mechanical advantage, meaning a bit less length of stroke, but a lot harder to push the pedal.
 

Fishfan

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It sounds electrical to me. If you have electronic ignition it could be your ignition module heating up. The biggest cause of that is a poor ground. You can check it with a digital Ohm meter. If you have more than a .5 ohm reading between the CPU case and Neg post on your battery, it is probably causing your problem. What happens when not properly grounded, the current flow will heat up the transistor in the CPU and it will open the circuit until it cools down. Not always the problem but it seems to be very common. It also heats up the coil so it is too hot to touch. That is where I would start.
I'm running an MSD E-Curve electronic distributor (it's an all in one unit, no separate box). I'll double-check the ground. Note that this setup did not change when I changed the the intake manifold and carburetor. But I did send the distributor unit away to be refurbed and maybe I didn't ground it properly when I reconnected everything.

Screen Shot 2022-11-17 at 6.03.03 PM.png
 

Fishfan

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You haven't said anything about how the choke is adjusted. A choke that comes off too early or too late can cause this.

There's also the fuel pump/pump rod to think about. Most guys just won't do the simple task of checking fuel pump volume with a soda bottle and a rubber hose, but I always suggest it anyway... Fuel pump pressure can be checked with a pressure gauge (like the Harbor Fright kit for example) that's not a lot of money.

Choke is electric. Seems to working fine. Fuel pump I replaced personally last year. Worked fine with the old carb/intake setup. I suppose it could be the issue but am doubtful.

About power brakes, this is only temporary while I figure out what the root cause of the stalling is. I have the new booster on order.
 

Gerald Morris

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I posted about this before but haven't been able to resolve it. Here's the situation. Car cold-starts perfectly. I drive it for a while and after about 30 mins I'll pull up to a stop sign or red light and it will stall. Engine temperature is not HOT but warm, normal. Restarting is difficult and often it will stall again when I shift in drive. The only solution so far is to let car sit for an extended period of time, like 30 minutes.

This has been ongoing since I swapped my intake manifold to accommodate my new 4-barrel Edelbrock 1406 carburetor.

What I've done so far:

• Disconnected my brake booster from the carb and plugged the port on the carb. I have a new booster on order because the existing one was causing the idle to drop when brake was applied, so I suspect the diaphragm inside is shot. Car is driveable without the booster (didn't come from the factory with a booster and I drove it that way for 13 years). I thought maybe the vacuum leak was causing my stalling problems.

• Plugged the vacuum port on the intake manifold that was connected to the AC controls, trying to eliminate any potential vacuum loss.

• Also, I disconnected my PCV valve from the valve cover and carb. Put a breather on the valve cover and a plug on the carb. Again, trying to eliminate any places of potential vacuum leak.

• Leaned out my idle adjustment because I thought maybe it was running too rich for warm operation.

None of the above has worked, so what can be causing my stalling?

I saw a suggestion for a similar problem on another forum for a different make of car that the carburetor float heights might be off. Now this is a brand new carb, so I'd like to think it came with the proper float adjustments from the factory but who knows? I guess I have to get in there and take it apart and see. Or perhaps the factory specs don't work well with my set-up? If so, what should I be looking for?

What other causes can we attribute my warm engine stalling to?

I have a problem rather opposite to yours, after having upgraded to the Edelbrock 1405. In this recent bit of less than balmy weather, the engine sputters, sneezes and coughs until over 200 F when opening the throttle much beyond cruise/idle. Once warmed up over 200, it breathes VERY well. I suspect fuel atomization issues causing Gertrude's "headcold." I need to check my fuel pump pressure as one of the last accessory issues, after having tuned it and checked that WELL, but I expect fuel pressure to be in Edelbrock spec. Is yours?

By this Sunday, I SHOULD have all the other loose ends dealt with. I might start my own thread about "sneezing Gertrude" for folks then. I suspect you also have a carb issue, albeit, a subtle one. Read your Edelbrock User's manuals, as I am now. Good Luck.
 

1970FuryConv

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I'm running an MSD E-Curve electronic distributor (it's an all in one unit, no separate box). I'll double-check the ground. Note that this setup did not change when I changed the the intake manifold and carburetor. But I did send the distributor unit away to be refurbed and maybe I didn't ground it properly when I reconnected everything.

View attachment 567971
I suspect the rebuilt distributor and the internal ECU. Heat or Chinese quality could be a problem.

When my 72 Fury had vapor lock, I would stop at say a NAPA store. It would start after I bought whatever, but then I'd take off from a stoplight and the car would bog. After 2 or 3 seconds the fuel pump overcame the vapor lock and I continued down the road. It had an Edelbrock 1406. The problem turned out to be lack of a fan shroud causing a slightly too-hot engine.

The 1406 ran rich and needed a rebuild. I eventually exchanged it for a rebuilt Carter 625.
 

HWYCRZR

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But did you replace or measure the fuel pump push rod when you replaced your fuel pump? I found that when cold with a short pushrod, it would start up and run. When it got warm or wanted to step on it it would shudder, and not want to star back up. It seemed when it cooled a bit it would pump fuel and start up. I found my push rod to be over a 1/4” short.
 

CBODY67

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As the engine will still turn over, but not start, I might lean toward the fuel pump push rod area. But not sure why the issues started with the intake manifold change?
 

jimmyessbee

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My 64 Newport came to me with an issue similar to yours. It also came with an Edelbrock carb and weiand intake. Like you, I chased vacuum leaks because that's what it felt like. I did decide to put the stock two barrel back on it. Upon pulling it apart, it appeared that when they swapped intake and carb, they reused the valley pan gasket (still blue) and added some rubberish intake gaskets. Perhaps that's normal, but that's not how I've done it. I got a new valley pan and put on the original carb and intake and that fixed the issue. It could have been an issue with the Edelbrock, but I do doubt that. I've got one on my Ford's 390 and it works perfectly. I think they're good carbs. But you can't have air leaks.
 

Fishfan

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I think I may have found and solved the issue. The wiring/connection from IGN to the coil was chintzy. I think it was heating up and somehow losing its conductivity. I think Sixpactogo was on the right track when he said electrical. I undid the chintzy stuff and put a new connector on and test drove it. Seemed fine. Tomorrow I'll reconnect the brake booster and PCV valve back to the carb and take for a longer test drive.
 

jimmyessbee

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I think I may have found and solved the issue. The wiring/connection from IGN to the coil was chintzy. I think it was heating up and somehow losing its conductivity. I think Sixpactogo was on the right track when he said electrical. I undid the chintzy stuff and put a new connector on and test drove it. Seemed fine. Tomorrow I'll reconnect the brake booster and PCV valve back to the carb and take for a longer test drive.
An old mechanic once told me... '95% of electrical issues are fuel delivery issues. And vice versa.'. It can get frustrating.
 

Fishfan

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An old mechanic once told me... '95% of electrical issues are fuel delivery issues. And vice versa.'. It can get frustrating.

Ha, that's a good one and apparently describes the issue I was having. Went for and extended test drive today after getting rid of the offending wire and butt connector and no issues so far. Big_John will be happy to know that brake booster is connected and boosting again though still excessively lowering my idle when brake applied. New booster should be here in about two weeks, until then just putting car in N at red lights and easing off the brake.
 

Loadrunner

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Leaned out my idle adjustment because I thought maybe it was running too rich for warm operation.

None of the above has worked, so what can be causing my stalling?

So electrical it was, but lean = stalling vs slightly rich = power & cooler running.

Set the mixture screws lean enough and you will hurt power and driveablility, lean enough and the engine will pop through the carburetor on sharp acceleration.

Note to self and others;

Try not to look straight down carb when fireball comes out while throttle goosing during "carb tuning" procedure.
 

jimmyessbee

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Try not to look straight down carb when fireball comes out while throttle goosing during "carb tuning" procedure.
This is one of those lessons that usually needs to be learned the hard way. I was convinced at one point that the sharp hood latch on the newer c bodies was designed to keep your head out of there.
 

Loadrunner

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The stench of singed facial hair including eyebrows lingers in your nostrils for a while...
 
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1970FuryConv

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This is one of those lessons that usually needs to be learned the hard way. I was convinced at one point that the sharp hood latch on the newer c bodies was designed to keep your head out of there.
The hood latch has a head magnet. I put a folded sock over the latch as protection from a bleeding scalp.
 

Big_John

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I was convinced at one point that the sharp hood latch on the newer c bodies was designed to keep your head out of there.

The hood latch has a head magnet. I put a folded sock over the latch as protection from a bleeding scalp.
I used to use a cut up tennis ball, but now I use a piece of pool noodle cut to wrap around the latch. I take it off and toss it down in the area in front of the radiator and it stays there until needed.
 
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