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#328160 - 05/25/09 10:39 AM Exactly WHY is my car hard to start when warm?
BossRide Offline
super street

Registered: 01/26/03
Posts: 1972
Loc: Southaven, MS
I've asked around and all my friends say it's "just how it is." I am having trouble believing that Mopars rolled off the showroom floors with a hard starting condition.

Cold- Turn the key, push the pedal to the floor to set the choke, Boom! Starts right up.

Runs good, drives nice... pull in and park... go to leave and either it fires right off if less than, say 15 minutes has passed, or it spins over and over and finally catches.

Trial and error of different procedures (pumping the gas, not touching the gas, giving it full throttle or partial throttle) is basically all the same.

Fresh 360... tuned up... (good plugs, wires, cap, etc..) new fuel tank, filter, and pump, 600cfm Holley carb with electric choke, timing on the money... what is the secret? Any thoughts on what to check or how to remedy?

Does YOURS fire right off when warm?
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#328161 - 05/25/09 10:44 AM Re: Exactly WHY is my car hard to start when warm? [Re: BossRide]
LimelightCuda Offline
enthusiast

Registered: 01/03/04
Posts: 294
Loc: The Garden State
My slant six equipped Scamp does the same thing. I think it is due to it boiling the fuel when it sits after it is fully warmed up but I'm not sure. My Barracuda with a 440 does not have this problem. My former Barracuda with a 318, which I had many years ago, would start up with a flick of the ignition switch, you didn't even have to give it any gas or even get in the car if it was warmed up.
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#328162 - 05/25/09 11:04 AM Re: Exactly WHY is my car hard to start when warm? [Re: LimelightCuda]
BergmanAutoCraft Offline
master

Registered: 11/28/03
Posts: 3476
Loc: Long Island, NY USA
Couple reasons.

First, fuel boils at 100 deg F. This was not so back in the day.

The only place fuel usually boils is in the bowls, because here it is not under pressure.

During heat soak, the fuel evaporates, and sometimes pushes out of the bowls into the motor, causing a flooding condition momentarily.

The extended cranking is to refill the bowls.

I have found wood spacers, and a cool running motor to comat this pretty well. I am also a proponent of electric fans, which keep good airflow over the motor at low speeds.
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#328163 - 05/25/09 11:16 AM Re: Exactly WHY is my car hard to start when warm? [Re: BossRide]
71valiant Offline
enthusiast

Registered: 04/21/07
Posts: 375
Loc: NE Oklahoma

My A-body has headers and they go right by my starter. I think it gets the starter hot and it cranks real slow when its hot.

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#328164 - 05/25/09 11:47 AM Re: Exactly WHY is my car hard to start when warm? [Re: 71valiant]
azmopardart Offline
Foot Fetish

Registered: 04/07/07
Posts: 2181
Loc: None of your business
All my stuff starts within 1-2 seconds, whether hot or cold
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#328165 - 05/25/09 11:54 AM Re: Exactly WHY is my car hard to start when warm? [Re: LimelightCuda]
1_WILD_RT Offline
Management Trainee

Registered: 01/15/04
Posts: 27347
Loc: Today? Who Knows?
Mine lights off instantly... I think the new fuel boils off due to engine heat.. In a modern fuel injected car where the fuel is injected & the fuel is always pressurized it's a non-issue but a carburator where the fuel sits on a hot engine....I've blocked the crossover & added a heat shield...

http://images.google.com/imgres?imgurl=h...sa%3DN%26um%3D1

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#328166 - 05/25/09 11:55 AM Re: Exactly WHY is my car hard to start when warm? [Re: azmopardart]
pushbutton Offline
super stock

Registered: 11/15/08
Posts: 1176
Loc: tennessee
Quote:

All my stuff starts within 1-2 seconds, whether hot or cold


Man thats fast! Wish my stuff would start that quick.

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#328167 - 05/25/09 12:17 PM Re: Exactly WHY is my car hard to start when warm? [Re: pushbutton]
SomeCarGuy Offline
master

Registered: 02/02/03
Posts: 6669
Loc: Someplace you aren't
Mine starts fast, I have aluminum intake, heat riser blocked. Eddy carb. No spacer, just two gaskets.

Is your timing chain tight?

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#328168 - 05/25/09 12:52 PM Re: Exactly WHY is my car hard to start when warm? [Re: SomeCarGuy]
RapidRobert Offline
Too Many Posts

Registered: 11/20/03
Posts: 25322
Loc: Lincoln Nebraska
k.i.s.s. next time BEFORE you crank it see if there's an A/P shot then pull the coil to dist wire & hold it 1/4" from ground & have someone crank it.
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#328169 - 05/25/09 04:23 PM Re: Exactly WHY is my car hard to start when warm? [Re: SomeCarGuy]
BossRide Offline
super street

Registered: 01/26/03
Posts: 1972
Loc: Southaven, MS
Quote:

Mine starts fast, I have aluminum intake, heat riser blocked. Eddy carb. No spacer, just two gaskets.

Is your timing chain tight?




I have an Offy aluminum intake, and the timing chain should be tight, the motor has around 5,000 miles on it since the rebuild.
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#328170 - 05/25/09 06:06 PM Re: Exactly WHY is my car hard to start when warm? [Re: BossRide]
MoparforLife Offline
Too Many Posts

Registered: 01/19/03
Posts: 25156
Loc: Upper Midwest
Like said above fuel boiling over. This is true especially with alcohol blendas they boil at a lot lower temp than even the poor gas we have now. HOLD the gas pedal to the floor while cranking till it starts allow to clean out just like you would a flooded engine. Essentially that is what you have.

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#328171 - 05/25/09 06:20 PM Re: Exactly WHY is my car hard to start when warm? [Re: BossRide]
JonC Offline
master

Registered: 01/21/03
Posts: 3371
Loc: Millinocket, Maine
This was my condition at one time and I found out the vacuum advance was hooked up to the wrong port on the carb. Started good cold but terrible hot. Just a long shot.

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#328172 - 05/25/09 07:18 PM Re: Exactly WHY is my car hard to start when warm? [Re: JonC]
BossRide Offline
super street

Registered: 01/26/03
Posts: 1972
Loc: Southaven, MS
Quote:

This was my condition at one time and I found out the vacuum advance was hooked up to the wrong port on the carb. Started good cold but terrible hot. Just a long shot.




I'm going to double check that, along with the coil wire and see about getting a heat shield or carb spacer.

Thanks for all of the tips and help.
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#328173 - 05/25/09 09:31 PM Re: Exactly WHY is my car hard to start when warm? [Re: BossRide]
rss Offline
super stock

Registered: 08/03/07
Posts: 874
Loc: Seattle, WA
This might make you feel better.

Mine has gotten to the point that it won't even start when warm. Nearly had it towed last week when I shut it down to fill up with gas. By the time the tow truck arrived it started and I was able to drive home. Fires up great cold, runs great, but if I turn it off and try to restart hot I can just crank away till the battery is nearly dead.

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#328174 - 05/25/09 10:11 PM Re: Exactly WHY is my car hard to start when warm? [Re: rss]
68Bullit Offline
mopar

Registered: 03/30/08
Posts: 566
Loc: Western NC
Mine did the same thing, and recently I put a wooden spacer there to help. It helped out some, but not much. Even with the wooden spacer the carb is too hot to the touch once the engine is up to temp. No heat riser or anything. I'm thinking about using some fuel line insulation next to see if that will help. My fuel line runs cloe to the header on the passenger side, and is routed up very close to the front of the engine block before it ties into the carb.

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#328175 - 05/25/09 10:20 PM Re: Exactly WHY is my car hard to start when warm? [Re: 68Bullit]
DaytonaTurbo Offline


Registered: 02/26/03
Posts: 17800
Loc: Manitoba, Canada
Quote:

Mine did the same thing, and recently I put a wooden spacer there to help. It helped out some, but not much. Even with the wooden spacer the carb is too hot to the touch once the engine is up to temp. No heat riser or anything. I'm thinking about using some fuel line insulation next to see if that will help. My fuel line runs cloe to the header on the passenger side, and is routed up very close to the front of the engine block before it ties into the carb.




If your fuel is boiling out like that your best bet is to just switch to an electric fuel pump with a return style regulator. That way when you turn your key to 'run' and the pump kicks on it fills up your carb bowls and the return style regulator keeps the fuel in the lines cooler plus stops the pump from overflowing your carb and pushing fuel past the needle/seat.
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#328176 - 05/25/09 10:22 PM Re: Exactly WHY is my car hard to start when warm? [Re: BergmanAutoCraft]
DaytonaTurbo Offline


Registered: 02/26/03
Posts: 17800
Loc: Manitoba, Canada
Quote:


During heat soak, the fuel evaporates, and sometimes pushes out of the bowls into the motor, causing a flooding condition momentarily.





How would this happen? Would not the evaporating/boiling fuel simply vent out of the bowl vent tubes?
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#328177 - 05/25/09 10:24 PM Re: Exactly WHY is my car hard to start when warm? [Re: 68Bullit]
1_WILD_RT Offline
Management Trainee

Registered: 01/15/04
Posts: 27347
Loc: Today? Who Knows?
Seriously try a heat shield, it deflects most of the engine heat around the carb...In order to clear the linkage I had to trim one corner a little but it works great... Not a pretty as some other spacers but more effective & I care more about function as I like to drive my car... And if your gonna drive it it's gotta start..


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#328178 - 05/25/09 11:05 PM Re: Exactly WHY is my car hard to start when warm? [Re: DaytonaTurbo]
hooziewhatsit Online   content
top fuel

Registered: 10/05/07
Posts: 2143
Loc: State of Jefferson
Quote:

Quote:


During heat soak, the fuel evaporates, and sometimes pushes out of the bowls into the motor, causing a flooding condition momentarily.





How would this happen? Would not the evaporating/boiling fuel simply vent out of the bowl vent tubes?




Unless it overloads the vents I watched as the secondary area on my carb got nice and moist with fuel after shutting it off once, as I listened to it boil

A wood spacer is going to be my next project.
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#328179 - 05/25/09 11:13 PM Re: Exactly WHY is my car hard to start when warm? [Re: DaytonaTurbo]
RapidRobert Offline
Too Many Posts

Registered: 11/20/03
Posts: 25322
Loc: Lincoln Nebraska
Quote:

How would this happen? Would not the evaporating/boiling fuel simply vent out of the bowl vent tubes?


It'd depend if it was heavier than air or not & it's probably still evaporating when he comes back then it gets sucked in when he cranks it
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