# Choke problem?



## 66_goat (Apr 10, 2007)

Hey guys I am new to this forum but I have a quick question. I have a '66 and I am having a difficult time starting the car after it's been running awhile or it heats up. I'm wondering if it's a choke problem on the carb? I'm confused as hell because it also has a hard time cranking when it's hot as well. Any ideas what's going on and how I fix the choke if that is what it is? Thanks.


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## jeremy (Apr 11, 2007)

sounds almost like vapor lock. I'm sure someone else will chime in though


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## 05GTO (Oct 6, 2004)

Is your Carb the original Carter AFB?


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## DaveH (Jan 20, 2006)

When you say it has a hard time cranking when it's hot - do you mean the starter is turning the engine over slow (in which case you may have a heat-soaked starter - a common Pontiac w/headers issue) or does it crank at normal speed but not fire? 

You can always disconnect the choke temporarily to see if it helps the problem.


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## 66_goat (Apr 10, 2007)

DaveH said:


> When you say it has a hard time cranking when it's hot - do you mean the starter is turning the engine over slow (in which case you may have a heat-soaked starter - a common Pontiac w/headers issue) or does it crank at normal speed but not fire?
> 
> You can always disconnect the choke temporarily to see if it helps the problem.


I guess I could disconnect the choke but I have no idea how....I have no experience with carbs. Someone else asked if it was the original carburator: It's not the original Carter AFB - it's an Edelbrock.

It seems to me though that it is most likely not the carb, it's just a "hot start" problem. I have had this problem ever since I've owned the car. It cranks normally when cold, but once it's hot, it hardly cranks at all. So what's my next step to solving the problem? Do I need to replace the starter or would something like the "hot shot" part from Painless wiring help boost the amperage to the solenoid (painless #30202)? I also found a Hot Start/Bump Start Solenoid Kit from Taylor (Taylor #383480). Would any of these help?


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## PHOTOGOAT (Feb 17, 2006)

66_goat said:


> I guess I could disconnect the choke but I have no idea how....I have no experience with carbs. Someone else asked if it was the original carburator: It's not the original Carter AFB - it's an Edelbrock.
> 
> It seems to me though that it is most likely not the carb, it's just a "hot start" problem. I have had this problem ever since I've owned the car. It cranks normally when cold, but once it's hot, it hardly cranks at all. So what's my next step to solving the problem? Do I need to replace the starter or would something like the "hot shot" part from Painless wiring help boost the amperage to the solenoid (painless #30202)? I also found a Hot Start/Bump Start Solenoid Kit from Taylor (Taylor #383480). Would any of these help?



It is either a timing issue, crappy battery or a weak starter. Big block Ponchos need a high torque starter because the engine will heat soak after it is shut off. Make sure your battery is good and at least 800 CCA as well.

Also, older cars may have corrosion inside the battery cables that you cannot see. It creeps up the insulator and knocks about 1/2 of your cranking amps out.

Food for thought......


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## aintmisbehavinn (Feb 9, 2006)

Check your timing. Make sure you don't have the rockers to tight.


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## 66_goat (Apr 10, 2007)

PHOTOGOAT said:


> It is either a timing issue, crappy battery or a weak starter. Big block Ponchos need a high torque starter because the engine will heat soak after it is shut off. Make sure your battery is good and at least 800 CCA as well.
> 
> Also, older cars may have corrosion inside the battery cables that you cannot see. It creeps up the insulator and knocks about 1/2 of your cranking amps out.
> 
> Food for thought......


Ok so I have a new battery and I just replaced all the new battery cables today, but it still has a hot start problem. My guess is that the timing may be a small issue to the problem, but my guess is it needs a new high torque starter. Any recommendations on what kind to get and where I could get one quick and cheap! Thanks!


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## 05GTO (Oct 6, 2004)

jeremy said:


> sounds almost like vapor lock. I'm sure someone else will chime in though


If your 66 is running the standard compression ratio of 10.75:1 a high torque starter is not needed, I believe your problem is a flooded engine or as Jeremy mentioned, "Vapor Lock",

I found this on Wikipedia; 



> Vapor lock is a problem that mostly affects gasoline-fueled internal combustion engines. It occurs when the liquid fuel changes state from liquid to vapor while still in the fuel delivery system. This disrupts the operation of the fuel pump, causing loss of feed pressure to the carburetor or fuel injection system, resulting in transient loss of power or complete stalling. Restarting the engine from this state may be difficult. The fuel can vaporize due to being heated by the engine, by the local climate or due to a lower boiling point at high altitude. In regions where higher volatility fuels are used during the winter to improve the starting of the engine, the use of "winter" fuels during the summer can cause vapor lock to occur more readily.
> 
> Causes and Incidence
> Vapor lock was far more common in older petrol fuel systems incorporating a low-pressure mechanical fuel pump driven by the engine, located in the engine compartment and feeding a carburetor. Such pumps were typically located higher than the fuel tank, were directly heated by the engine and fed fuel directly to the float tank inside the carburetor. Fuel was drawn under negative pressure from the feed line, increasing the risk of a vapor lock developing between the tank and pump. A vapor lock being drawn into the fuel pump could disrupt the fuel pressure long enough for the float chamber in the carburetor to partially or completely drain, causing fuel starvation in the engine. Even temporary disruption of fuel supply into the float chamber is not ideal; most carburetors are designed to run at a fixed level of petrol in the float chamber and reducing the level will reduce the air:fuel mixture delivered.
> ...


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## DaveH (Jan 20, 2006)

It sounds to me like your starter is becoming heat soaked and needs to be replaced. You don't _need a high-torques starter, a replacement will do, but I am happy that I put a high-torque starter on my '70. Starters would only last a couple years and it seemed like I was alway replacing them. I replaced it with a high-torque starter from Ames Performance Products and have no problems since - but not cheap, listing at $209. I believe the high-torque starter's smaller size helps it get more cooling air and it is not as close to the headers as the original starter. 

As a qualifiers: 
1. I must admit that since the car is not a daily driver anymore the starter doesn't get anywhere near the exercise that it has in past years. 

2. I also have a '66 with an ancient stock starter, 12 to 1 pistons, and headers which spins the engine way faster than the high-torque starter and have never had a heat-soak problem with it._


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## 66_goat (Apr 10, 2007)

Hey guys, thanks for your help and input. I think that being I'm located in AZ the problem with the goat is definitely "vapor lock". Did stock 1966 GTO's ever come with a fuel vent return line? Because mine does not have it. Should it not run from the fuel pump back to the gas tank? I've come to the conclusion that this or simply wrapping the fuel lines with heat insulation is about my only option. Any more input on this thread would be appreciated.


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## Guest (May 31, 2007)

*starting proplems*

does you car still turn over easy but does not start,,if it does this,, check your fuel lines,,if you have OEM, or rubber type fuel line, as they get old they can collapse from pressure causing your engine to starve for gass, after it cools down the hose can return to normal shape and it will start again,, also check your Fuel filter,,

but this also can be a bad starter,, works good when cool,, when it gets hot it locks up,,,hope this helps


DIZZY


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## Rukee (Feb 8, 2007)

*when hot...*

cranks normal speed = fuel related
cranks slow = timing too far advanced or weak starter


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## PONTIACBEN (May 6, 2006)

Try Running The Highest Octane Fuel You Can Find, And Maybe Some Octane Boost Also.. That Will Help With The Vapor Lock Issue. Another Thing You Can Do Is Run A Heat Sink On The Fuel Lines.
My 69 Had This Same Problem And I Re-routed All Of My Fuel Lines Completely Away From The Block, And Put In A Reman Napa Starter. Now She Starts Great Every Time! You Also Might Try A Starter Heat Shield...


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## 66_goat (Apr 10, 2007)

Rukee said:


> cranks normal speed = fuel related
> cranks slow = timing too far advanced or weak starter


Cranks normal speed when cold and fires right up every time.
Cranks a little slower, sometimes not at all - like the starter is dying on me or something when hot. Most of the time I'll crank it again and although it struggles for a few seconds I can usually get it to fire up.

I like the suggestions....I'll try using a higher octane and I'll check the fuel lines. I think the OEM starter is just fine, maybe simply installing a heat shield would do the trick. I'll look into that as well.


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## Rukee (Feb 8, 2007)

Higher octane won`t help if it cranks fine cold but cranks slow hot. You either have too much timing or the starter motor is weak.


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## 05GTO (Oct 6, 2004)

66_goat said:


> Hey guys, thanks for your help and input. I think that being I'm located in AZ the problem with the goat is definitely "vapor lock". Did stock 1966 GTO's ever come with a fuel vent return line? Because mine does not have it. Should it not run from the fuel pump back to the gas tank? I've come to the conclusion that this or simply wrapping the fuel lines with heat insulation is about my only option. Any more input on this thread would be appreciated.


Some of the 66 Goats with a 4 bbl and A/C used a 1/4" ID vapor return pipe, the fuel supply pipe should be 5/16". My 66 is a non-A/C 4 bbl and does not include the vapor return line. My metal fuel line is routed from the rear of the car inside the drivers side u-channel frame up to the firewall area and *then is routed inside the boxed frame connecting to a rubber hose which was routed out of the frame around the front upper control arm and connects to the fuel pump. *

I also think your problem is vapor lock and by running the fuel line inside the front frame should protect the line from the engine heat.


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## BobG (Dec 20, 2006)

OK. He said that it cranks SLOW or NOT AT ALL when hot, but cranks fine when cold. 

The car cranks fine when cold.
The car cranks SLOW when hot. Vapor lock in the fuel line will not inhibit the cranking of the engine. (unless you crank it so long that you wear the battery out.)

I would guess that this would pretty much preclude a vapor lock problem. 

I'm with the idea of a heat soaked starter or possibly a timing issue, but I'd tend to lean toward the starter as the culprit. easy way to check would be to put a timing light to it and see. If the timing is okay, replace the starter.


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## lars (Sep 28, 2004)

If your problem is that the starter is not turning over when you're heat soaked, install a better set of battery cables.
When the starter is hot, its amp draw requirement goes way up. The stock battery cables are puny little 1-gauge wires. I've been able to fix almost every hot-crank problem on GTOs by installing the big, fat, heavy duty Belden battery cables available from NAPA. These will flow the amperage required for a hot starter, and will make it spin over fine when hot.


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## judgeman6970 (Feb 11, 2007)

i've owned a-body pontiacs(v-8) for years.....what has worked for me EVERY time, with absolutely zero hot start problems is no modification at all....a good battery, oem cables/wiring in good condition, standard gm hi-torque starter and most importantly, a new gm(not rebuilt) starter solenoid with the "correct" spring inside(known as the "big block" spring)...its a lighter spring and needs less amps to pull in.......Also, a solenoid heat shield can't hurt!!!....just my opinion, but ALL my GTO's start as well hot as they do cold!!


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## lars (Sep 28, 2004)

I'll agree with that. The problem with these cars is that they have had so many poor quality aftermarket parts installed on them over the past 30 to 40 years that the problems tend to add up. When you get an old Checker Auto starter with a partially corroded set of 2-gauge flimsy cables with a 3 year old battery (with a 2-year warranty), you tend to get hot-start problems. My experience has been that the first thing to do is install a good set of heavy duty cables (since the cables seem to be the most neglected and taken-for-granted part of the system), but you make a good point: If the entire system is to the factory spec, it will work correctly, whether hot or cold.


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## judgeman6970 (Feb 11, 2007)

yeah...like my friend always says about these cars..."they started hot or cold when they were new, and didnt need super-duper starters or re-located solenoids"........and ur right about the cables, everyone "assumes" they are good enuff*_*


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