302 dies when hot. - Vintage Mustang Forums
Vintage Mustang Forum
HomeForumGalleryClassifiedsAbout UsAdvertiseContact Us
» Auto Insurance
» Featured Product
Go Back   Vintage Mustang Forums > General Discussion > Vintage Mustang Forum
Vintage-Mustang.com is the premier Ford Mustang Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools
Old 07-27-2010, 02:37 PM   #1 (permalink)
Junior Member
 
Vegas72's Avatar
 
Join Date: Jul 2010
Location: Henderson, NV
Posts: 7
Default **302 dies when hot** Fuel is boiling in carb

Hey everyone,

I'm new to the forum, and have recently purchased a 72 Convertible with the Mach 1 Package. Fun car, but we're still getting to know each other. What I know now is that she doesn't like the desert! Originally thought I had an electrical issue, but now I'm really stumped! This is driving me nuts!

Runs like a champ when cool. After it's hot, it will rev, and idle OK, but when you put a load on it, it just dies. Here’s what I’ve done since the problem began, and what I am observing:

Parts
• New carb (already had, so put it on
• Hard metal fuel supply lines (at carb)
• New coil (Mallory resistor coil)
• New electronic distributor internals (Mallory)

Observations
• The fuel bowls are full
• Timing at 12 btdc
• The fuel filter is nice and full when cold, but as temps rise, fuel filter drains to near empty, and I can see irregular spurts of fuel every few seconds into the near empty filter. However, bowls are full, so fuel starvation should not be a problem, correct? Or, could pump cavitation cause an issue, even with full fuel bowls?
• Once engine reaches max temps, at idle, if I try to hit the accelerator, it just dies.


I have a Carter fuel pump with about 2k miles from another project, which I could try. I also have recently rebuilt the old Holley 1850/600, which I could swap, but somehow I don't think that's the issue. I was having this problem with the old carb before rebuilding it.

Thanks to all for looking!
-Sean
__________________
1972 Mustang Covertible 302 w/ Mach 1 Package

Last edited by Vegas72; 07-27-2010 at 08:43 PM. Reason: Change title.
Vegas72 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 07-27-2010, 02:49 PM   #2 (permalink)
Moderator
 
HoosierBuddy's Avatar
 
Join Date: Aug 2002
Location: Probably in the garage
Posts: 6,307
Default

It's interesting that your fuel bowls are full, but I still think you are looking at a classic vapor lock situation.

If you want to test for this easily and cheaply, (and fix the problem at least temporarily) buy a Mr. Gasket 12S (or similar) electric external fuel pump. They sell for about $35. Mount it at the tank between your hard line and your tank using hose. You can power it from a toggle switch.

That pump will work fine inline with your mechanical pump. You won't have to change anything under the hood.

If it's hot out, or you are having fuel delivery problems, turn on the auxilery pump and it will insure that you have adequate pressure all the way to the fuel bowls. If it's cool or even if it fails (since it is sort of a cheap-piece-o-junk as far a fuel pumps go) you don't need to run it at all. It won't keep your mechanical pump from being able to draw fuel from the tank even if it's off.

I ran one of those for a year and it worked great. It's a little noisy, but I never had another vapor lock problem. Eventually, I switched to an in-tank electric fuel pump...but that's a HECK of a lot more money and trouble to install.

If it doesn't fix your problems...I'll be shocked and amazed.

Phil
__________________
http://forums.vintage-mustang.com/at...s-dsc25105.jpg

"Two barks means faster!" Enzo

Last edited by HoosierBuddy; 07-27-2010 at 02:51 PM.
HoosierBuddy is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 02:54 PM   #3 (permalink)
Junior Member
 
Join Date: Jul 2010
Location: Michigan
Posts: 4
Default

Agree it could be vapor lock, out of interest where did you buy the car from and when? How much fuel have you put in? Could be a winter fuel with a much higher vapor pressure than you would want for the dessert.
brit73 is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 03:42 PM   #4 (permalink)
Junior Member
 
Vegas72's Avatar
 
Join Date: Jul 2010
Location: Henderson, NV
Posts: 7
Default

Thanks guys.

Well, for $35 it may be worth a try. However, with fuel in the bowls, how can it be fuel pressure related? I mean, the fuel is in there where it should be, right?

Car was purchased here in Vegas. It's summer fuel, and I've run a few tanks through since owning it. Who knows. Maybe I did get a bad batch of fuel. I wonder if there's an additive that I should try.
__________________
1972 Mustang Covertible 302 w/ Mach 1 Package

Last edited by Vegas72; 07-27-2010 at 03:44 PM.
Vegas72 is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 04:10 PM   #5 (permalink)
Moderator
 
HoosierBuddy's Avatar
 
Join Date: Aug 2002
Location: Probably in the garage
Posts: 6,307
Default

Quote:
Originally Posted by Vegas72 View Post
Thanks guys.

Well, for $35 it may be worth a try. However, with fuel in the bowls, how can it be fuel pressure related? I mean, the fuel is in there where it should be, right?
But you don't have any fuel pressure, or you wouldn't be seeing vapor in the fuel filter. What I think you're seeing is the pump cavitating as the gasoline is boiling in the fuel pump. Once that happens, you lose prime on the pump, and fuel pressure to the carburetor. The engine can empty the primary fuel bowl in a few seconds once you open the throttle.

Phil
__________________
http://forums.vintage-mustang.com/at...s-dsc25105.jpg

"Two barks means faster!" Enzo
HoosierBuddy is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 04:16 PM   #6 (permalink)
Junior Member
 
Vegas72's Avatar
 
Join Date: Jul 2010
Location: Henderson, NV
Posts: 7
Default

Thanks Phil. It does look like the pump is cavitating when hot, and I understand that with a weak pump, fuel bowls can empty in a hurry. However, when the engine dies, the fuel bowls are completely full. That's what is baffling to me.
__________________
1972 Mustang Covertible 302 w/ Mach 1 Package
Vegas72 is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 06:33 PM   #7 (permalink)
Senior Member
 
Join Date: Oct 2006
Location: SE Virginia
Posts: 118
Default

Gotta go with HoosierBuddy on this one, Vapor Lock.
Might try some fuel dryer for the Ethanol, but don't think that's it.
68FBMustang is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 07:25 PM   #8 (permalink)
Joe
Senior Member
 
Join Date: Apr 2010
Location: Imperial Beach, CA
Posts: 1,042
Default

Even after you shut your engine down, there is still residual pressure in the line. (I got fuel in my eye finding this one out when I unseated a carb inlet needle on a motor I had just shut down.) Therefore, after your car dies, there is still enough pressure in the line to fill the bowls back up with fuel by the time you open the hood, since the engine is no longer consuming any. That's my theory, anyway.
__________________
'65 Coupe, 302, Autolite 4100, C4, 2.80
'72 Grande, 351C, Motorcraft 2100, FMX, 2.75

Last edited by Joe; 07-27-2010 at 07:26 PM. Reason: more
Joe is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 07:31 PM   #9 (permalink)
Junior Member
 
Vegas72's Avatar
 
Join Date: Jul 2010
Location: Henderson, NV
Posts: 7
Default

Think I will try the electric pump. However, wondering if I should bolt up that Carter pump I have on the bench, just to see if the Autozone pump that the other guy put on has taken a dump. Wouldn't be surprised!
__________________
1972 Mustang Covertible 302 w/ Mach 1 Package
Vegas72 is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 08:47 PM   #10 (permalink)
Junior Member
 
Vegas72's Avatar
 
Join Date: Jul 2010
Location: Henderson, NV
Posts: 7
Default

Ok guys, thanks for all of the replies, but it looks like I have found the problem. I let it get good and hot, and shut it down. Heard, then saw fuel squirting from carb. Looked through the temporary site plugs to see the fuel jumping around. Is this incredibly rare? I only have an idiot light, because I haven't had time to install a temp gauge in the few weeks that I've owned the car. The radiator has been drained, and filled a few times, and has fresh coolant. It is flowing and cooling. However, this is Vegas, and it is damn hot under the hood.

What should I do to help prevent this? Thanks again!

-Sean
__________________
1972 Mustang Covertible 302 w/ Mach 1 Package
Vegas72 is offline   Reply With Quote Quick reply to this message
Old 07-27-2010, 10:18 PM   #11 (permalink)
Junior Member
 
Vegas72's Avatar
 
Join Date: Jul 2010
Location: Henderson, NV
Posts: 7
Default

Going to try a whole lot of heat shielding material for the fuel lines, headers, and a heat shield for the carb. The exhaust also runs very close to the fuel line exiting the tank, so I'm going to shield it as well. This desert is hot. Hopefully this stuff helps! Will let you know.
__________________
1972 Mustang Covertible 302 w/ Mach 1 Package
Vegas72 is offline   Reply With Quote Quick reply to this message
Old 07-28-2010, 12:03 AM   #12 (permalink)
Senior Member
 
Jim_Williamson's Avatar
 
Join Date: Mar 2002
Location: Hesperia, Ca. 92345
Posts: 1,976
Default

I hear that header heat tape works wonders. Available at any speed shop and less than the electric pump and easier to install.
__________________
65 Vert. BarnFind. 5.0 EFI, AOD Oh, so sweet in [color:blue]Intense Blue Pearl[/color] 69 Sportsroof 6 Cyl 3 speed stick for now
http://webpages.charter.net/jrw642/Barnfind.jpg http://webpages.charter.net/jrw642/6...sportsroof.jpg
Jim_Williamson is offline   Reply With Quote Quick reply to this message
Old 07-28-2010, 02:19 AM   #13 (permalink)
Senior Member
 
pabear89's Avatar
 
Join Date: Apr 2004
Location: So Ca
Posts: 1,181
Default

A simple 1/2in rubber hose slid over the metal pump to carb line helps keep it from vaporing/boiling the fuel.
__________________
If it's already broken....I can't hurt it.
pabear89 is offline   Reply With Quote Quick reply to this message
Old 07-28-2010, 09:01 AM   #14 (permalink)
Senior Member
 
Blues Power's Avatar
 
Join Date: Mar 2010
Location: Up Yonder in them there hills
Posts: 2,785
Default

id put my money on the coil, new does not always mean it works, also check for loose or int connection
__________________
1970 Mach 1 San Jose built Dec 23 1969. Marti says 1 of 7. Purchased in 1987. Original family owner of the powertrain 351C 2v FMX.


1993 GT 11,000 miles, Built 2-12-93 Auto, 3:27 Axle, cloth, sunroof. Untouched except for rubber and battery, Purchased new 8-3-93. still has the factory windshield fluid and new car smell.


http://i280.photobucket.com/albums/k...ior2010011.jpg


http://i280.photobucket.com/albums/k...ior2010014.jpg
Blues Power is offline   Reply With Quote Quick reply to this message
Old 07-28-2010, 09:05 AM   #15 (permalink)
Senior Member
 
68RCodeConv's Avatar
 
Join Date: May 2003
Location: Houston TX - I drive mine.
Posts: 9,534
Default

You MUST have an insulating spacer between the carb and intake. Aluminum is not an insulator. If you have an aluminum spacer ditch it and get a phenolic (insulating) one. The thicker the better - 1" if you have the clearance. Don't buy the cheap generic ones as they might be warped. I have a Moroso on mine. Really doesn't matter if it is 4-hole or not but make sure the carb seals to it.
__________________
John Bednorz

1967 Shelby GT350, dark green, 347 stroker, 5-speed, inboards, #2206
1973 Mustang Convertible, white/white, black stripes, Q-code (351C-4V), ram air.
1968 1/2 428 CJ convertible, R-code, red/deluxe red, auto, finally finished.
"If you find the car of your dreams, ignore the price guides and pay whatever you have to in order to get it."
68RCodeConv is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are Off


Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 06:55 PM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.3.2 ©2009, Crawlability, Inc.