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  Mustangsandmore Forum Archive
  '64 1/2 to '68 1/2 -- The Classic Mustang
  Once engine's hot it's hard to restart, help!

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Author Topic:   Once engine's hot it's hard to restart, help!
ImBigE
Journeyman

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posted 09-29-2006 10:29 PM     Click Here to See the Profile for ImBigE        Reply w/Quote
I have a 1968 Mustang, 289, 3-spd, 2-barrel carb, mostly original and in close to excellent condition, engine is spotless, 85k with no extra's, no AC, power steering or the like.

The issue is this: When I take the car out for a ride, once the engine heats up, if I turn the engine off it will not restart. Or it's very difficult to restart. Usually I have to wait for the engine to cool down before it will start again. Ocassionally if I hold the gas pedal all the way to the floor and crank the engine long enough it will start. Also, I'm having trouble when it shuts down, it diesel's now, this is a recently new development.

The carb has been completely replaced and at one point a new one was installed, but that didn't fix the problem so I went back to the original carb.

If you have any suggestions or have heard of this type of issue and can offer some advice I would greatly appreciate it!

rmousir
Gearhead

Posts: 1124
From: Amelia, Ohio
Registered: May 2003

posted 09-29-2006 10:43 PM     Click Here to See the Profile for rmousir        Reply w/Quote
not to sure about this. Could it be vapor lock??? You could do a search on the forum for that.

Richard.

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rmousir
'66 Mustang Coupe
Ford Blue & white stripes
95 roller 302, C4 Auto
Offy 360 intake & Holley 4 bl carb
grab-a-track 620s, 4.5 leafs, 1.25" drop blocks

Dave Gibson
Moderator

Posts: 10769
From: Norfolk, Virginia, USA M&M#166 MCA#47921
Registered: Aug 99

posted 09-29-2006 10:53 PM     Click Here to See the Profile for Dave Gibson        Reply w/Quote
Sounds like vapor lock issue to me. Check the routing of the fuel line from the fuel pump to your carb. Is it a solid metal line or was it replaced with rubber fuel line?? Shouldn't be to hard to replace with out any extras in the engine compartment.

Welcome to M&M! Almost forgot my manners. Stop by "Sam's Place" and say "Hi" to the gang when you have a chance. Enjoy!

Dave & Terri

------------------
'65 Mustang Fastback
'66 Mustang Coupe
'02 Explorer XLT
Common sense isn't common anymore.

mustangboy
Gearhead

Posts: 1343
From: Ont, Canada
Registered: Mar 2002

posted 09-29-2006 11:21 PM     Click Here to See the Profile for mustangboy        Reply w/Quote
Sounds like your timing might be too far advanced.When you say its hard to start do you mean its cranks slowly or it cranks normal and just won't fire up?..If its hard to crank I would suspect timing too far advanced or just a tired starter/poor connections or weak battery.

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68 J-Code,Sprint,306 4 speed,4.11s 13.69@101...............
66 coupe 289 4 speed, 3.20 cruiser http://mustangsandmore.50megs.com/MembersPics/mustangboy.html http://mustangsandmore.50megs.com/MembersPics/mustangboy2.html

68 Coop
Gearhead

Posts: 5847
From: Mesquite, NV. 89027
Registered: Oct 2004

posted 09-30-2006 02:02 AM     Click Here to See the Profile for 68 Coop        Reply w/Quote
I was totally shocked how much easier my car started when I bought my new battery, but I agree with the timing, back it off a little and try it again. Test your battery too, ya never know, summer months are murder on these things.

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William
M&M# 4256
MCA# 64831

68 Coupe
289
C4
3:55's/Trac-Lok

68 Coop
Gearhead

Posts: 5847
From: Mesquite, NV. 89027
Registered: Oct 2004

posted 09-30-2006 03:05 AM     Click Here to See the Profile for 68 Coop        Reply w/Quote
Try running 93 octane gas and see if that helps any also.

EDIT: Something else, are you running points or electronic ignition??? If points, you might as well do a complete tune-up on it, unless it's had one recently. We will help ya in any way we can, and Welcome to M&M.

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William
M&M# 4256
MCA# 64831

68 Coupe
289
C4
3:55's/Trac-Lok

[This message has been edited by 68 Coop (edited 09-30-2006).]

Dreamcometrue
Gearhead

Posts: 903
From: New-Brunswick,Canada
Registered: Apr 2004

posted 09-30-2006 10:48 AM     Click Here to See the Profile for Dreamcometrue        Reply w/Quote
Warm welcome to M&M!
I have seen that happen when starter gets too much heat from the headers or the engine. Started great once it cools off.
You should investigate that route too.
Rino

ImBigE
Journeyman

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posted 09-30-2006 02:25 PM     Click Here to See the Profile for ImBigE        Reply w/Quote
Wow, you guys are quick wtih suggestions! This is a great forum, hopefully with some help I'll be able to get this all figured out!

Vapor Lock doesn't seem to make sense to me as the gas line (original metal line) doesn't seem to be to close to any heat source. I'm stumped here, would the fact that it's the original metal line make a difference?

This Mustang truly holds the classic "Little Old Lady Story". I purchased it 19 years ago from the original owner who's husband bought it for her in 1967 to use as a grocery getter, it never left the garage and is still in showroom quality. I showed it for a number of years as well, however now it only comes out of the garage a couple times a year.

If memory serves me correctly this problem cropped up a number of years after I had the car. I've tried everything and have never been able to pinpoint the issue. Carb, timing, lines, you name it, but still it continues to happen.

I'm going to check the timing again and make sure everything is fine on that front. Oh and no electronic ignition here! This car truly has many of the same parts on it now as it came off the line with! Anything that I have had to replace only led to it's original part being nicely boxed up and put away!

Please keep you suggestions coming, this has been a mystery I've been trying to solve for a number of years and I'm now thanking the heavens for the internet!

mustangboy
Gearhead

Posts: 1343
From: Ont, Canada
Registered: Mar 2002

posted 09-30-2006 02:33 PM     Click Here to See the Profile for mustangboy        Reply w/Quote
You never did say if the engine cranks slowly once its hot or if it still cranks the same speed as when its cold and just doesn't fire up right away?..We need to know this to diagnose the problem.

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68 J-Code,Sprint,306 4 speed,4.11s 13.69@101...............
66 coupe 289 4 speed, 3.20 cruiser http://mustangsandmore.50megs.com/MembersPics/mustangboy.html http://mustangsandmore.50megs.com/MembersPics/mustangboy2.html

ImBigE
Journeyman

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posted 09-30-2006 03:32 PM     Click Here to See the Profile for ImBigE        Reply w/Quote
I did overlook that didn't I? Well it cranks up normally, it gets no slower.

SugarlandStang
Journeyman

Posts: 98
From: Sugar Land, TX
Registered: Dec 2005

posted 09-30-2006 04:37 PM     Click Here to See the Profile for SugarlandStang        Reply w/Quote
I'm no expert, but vapor lock is the first thing I thought of. I might suggest checking the entire fuel line for posible heat source. Perhaps a small exhaust leak. Putting an plastic insulator around the fuel line as it enters the engine compartment would be a cheap fix. They sell em at your local parts store.

Good luck and welcome to M&M!

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Keith
67 Mustang Coupe
351W C4
3:80 limited slip
http://www.i62.photobucket.com/albums/h87/kleinhenz4202/P1010066.jpg

68 S-code GT
Gearhead

Posts: 3835
From: Sayreville, NJ, US
Registered: Mar 2000

posted 10-01-2006 10:36 AM     Click Here to See the Profile for 68 S-code GT        Reply w/Quote
If the engine were slow to crank after turning it off I would check the starter or the battery. If it cranks fine but will not start I would think that itís a fuel thing. If you hook up an electric fuel pump, it will put the fuel under pressure and raise the boiling point.

indyphil
Gearhead

Posts: 3394
From: Senoia, G.A. USA
Registered: Jul 2002

posted 10-02-2006 09:13 AM     Click Here to See the Profile for indyphil        Reply w/Quote
My 68 2 barrel did exactly the same thing.

Ive not had any problems after putting a phenolic spacer under the carb - but I switched to an aluminum 4 barrel intake manifold and edelbrock carb.

The main things that helped involved keeping the engine and the carb cooler. It didnt ever have much to do with routing the fuel line - it was never anywhere near the headers. Your fuel pump might need replacing, but the other thing I though of is that you might try replacing the fuel filter, and potentially the sending unit in the tank (which has a screen).

The basic effort here is in getting the pump to pump MORE fuel when cranking to fill the bowl better. If your not pumping enough fuel or your carb is too hot, then it just boils before it can fill up never will be rich enough to fire. You can always carry a can of easy start with you until you get this sorted (that was my method for a few weeks)

Ryan Wilke
Gearhead

Posts: 3237
From: Stanton, Michigan, zip 48888
Registered: Oct 2000

posted 10-02-2006 11:09 AM     Click Here to See the Profile for Ryan Wilke        Reply w/Quote
BigE,
First off, WELCOME TO M&M!

CONDITIONS & SYMPTOMS:
Your '68 sounds to be mostly a stock setup with still lots of original (38yrs old) parts. You replaced the carb (no change) so you went back to the original carb. You checked the timing, checked the fuel lines, but it still will not restart once the engine heats up. However, once you wait for the engine to cool down, it will start again. Although on occasion, if you hold the gas pedal all the way to the floor and crank the engine long enough it will start.

MY OPINION ON PROBLEM:
Based on the above information, I agree with other folks that it's a fuel issue. I'd say that you've got crud in your carb that allows fuel to drain into the intake after you shut it down and this causes a 'flooding' condition. If you let it set to cool off long enough, the drained fuel dries out or if you put the pedal to the floor, that sometimes clears out the the flooding condition.

THE FIX:
With the engine cool, I'd ground the coil wire to a intake bolt (to prevent any chance of starting) and remove the fuel line from the carb. Carefully place the end of the fuel line into a clean, one gallon white jug - such as a milk jug. Attach a section of clean fuel hose as an extension to the line, if necessary. Have a friend crank the engine over while you hold the line in the jug. Crank the engine enough to allow the fuel pump to deliver 0.5 to .75 gallon of fuel to the jug, then stop cranking. Now carefully inspect the fuel inside the jug by holding a bright flashlight (an AC trouble light works, but be careful with) to the side of the jug, looking for any crud that may be in the fuel. I'd bet there will be. I'd bet that a good inline fuel filter and giving your carb a good cleaning, blowout with pressurized air and a resetting of the floats will cure the flooding problem.

OTHER PROBLEM:
Many times a "dieseling" issue is typically cured by messing with the timing. However, then mileage/power suffers, because the timing advance has been reduced for the sake of eliminating the 'dieseling' conditon, rather than stepping up to a better grade of fuel. That's the wrong approach. The better fix is to run better fuel. Run or drain out the current fuel load. Refill the tank with some quality premium-grade gasoline. I'll bet that cures the dieseling or 'run on' issue. Many folks forget that the REGULAR-GRADE fuel octane in 1968 was near what PREMIUM-GRADE fuel octane levels are today.

"Just my opinion, your results may vary".
Good Luck!
Ryan

beachbum
Gearhead

Posts: 307
From: Florida
Registered: Oct 2001

posted 10-02-2006 11:41 AM     Click Here to See the Profile for beachbum        Reply w/Quote
I had a simular problem when my engine got to operating temperature. The car always ran fine at operating temperature until I shut the engine down and tried to start it up right away. There is where I had the problem, trying to start the engine when it was hot, but if I waited a while it would start right up again....... I changed the coil and that fixed the problem. My guess is the coil wires seperated from the engines higher temperature right after shut down.

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