Fuel starvation/vapor lock?? Paul67 or anybody . . .
#1
Le Mans Master
Thread Starter
Fuel starvation/vapor lock?? Paul67 or anybody . . .
I'm getting fuel starvation on these hot days, not sure if it's a vapor lock problem or not, but tend to think so. Could be a problem with the fuel pump.
I'm running essentially the same fuel delivery system as Paul67 with an Edelbrock replacing the original Holley, in-line filter just before the carburetor. But, I have a flex line from the fuel pump up to the filter, and then about 8 inches or so of solid line before entering the carburetor. This arrangement makes me doubt somewhat that the vapor lock is occurring in the line itself.
Paul67, I notice your carburetor appears to have an insulator between the carb and the intake which I don't have. Could the lack of such an insulator be the source of my discontent? Thoughts?
I'm running essentially the same fuel delivery system as Paul67 with an Edelbrock replacing the original Holley, in-line filter just before the carburetor. But, I have a flex line from the fuel pump up to the filter, and then about 8 inches or so of solid line before entering the carburetor. This arrangement makes me doubt somewhat that the vapor lock is occurring in the line itself.
Paul67, I notice your carburetor appears to have an insulator between the carb and the intake which I don't have. Could the lack of such an insulator be the source of my discontent? Thoughts?
Last edited by Ron Miller; 08-11-2007 at 04:54 PM.
#2
Le Mans Master
Member Since: Nov 2000
Location: Going too fast over the hill. Iowa
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All my vapor lock, hot weather, and starting after a long period of storage problems were solved by replacing the mechanical pump with a small electric pump installed at the fuel tank hose.
My inline filter is back there too, and the 3/8 steel line to my AFB has a piece of slit rubber fuel line covering it to keep the fuel colder.
Nothing is perfect. Electric pumps die too. I'm just happy that my daily use of the car in hot weather is no longer troubled by vapor lock or fuel boil out.
My inline filter is back there too, and the 3/8 steel line to my AFB has a piece of slit rubber fuel line covering it to keep the fuel colder.
Nothing is perfect. Electric pumps die too. I'm just happy that my daily use of the car in hot weather is no longer troubled by vapor lock or fuel boil out.
#3
Le Mans Master
Thread Starter
All my vapor lock, hot weather, and starting after a long period of storage problems were solved by replacing the mechanical pump with a small electric pump installed at the fuel tank hose.
My inline filter is back there too, and the 3/8 steel line to my AFB has a piece of slit rubber fuel line covering it to keep the fuel colder.
Nothing is perfect. Electric pumps die too. I'm just happy that my daily use of the car in hot weather is no longer troubled by vapor lock or fuel boil out.
My inline filter is back there too, and the 3/8 steel line to my AFB has a piece of slit rubber fuel line covering it to keep the fuel colder.
Nothing is perfect. Electric pumps die too. I'm just happy that my daily use of the car in hot weather is no longer troubled by vapor lock or fuel boil out.
#4
Team Owner
Ron,
I'm fooling about in the garage and saw your message. Yes, I have the Edelbrock #9266 (0.320") insulator but I put that on just as a matter of caution three years ago When I dumped the Holley out of frustration. I am sure it has some effect on percolation but I have not tried the carb without it.
You have had the #1406 on for 1-2 seasons previous to this? And it did not give problems? I suspect then that the fuel pump is going bad.
BTW, what ambient temps? Also, I am confused as to where the eight feet of flex line is installed....
I'm fooling about in the garage and saw your message. Yes, I have the Edelbrock #9266 (0.320") insulator but I put that on just as a matter of caution three years ago When I dumped the Holley out of frustration. I am sure it has some effect on percolation but I have not tried the carb without it.
You have had the #1406 on for 1-2 seasons previous to this? And it did not give problems? I suspect then that the fuel pump is going bad.
BTW, what ambient temps? Also, I am confused as to where the eight feet of flex line is installed....
#5
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Location: Going too fast over the hill. Iowa
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The one in my car looks like this
http://cgi.ebay.com/ebaymotors/PUROL...QQcmdZViewItem
PS about 2/3 down this web page is a pic of the pump in my car:
http://www.corvetteforum.net/classic...e/index5.shtml
At the bottom of the web page is a link to the wiring of the relay (triggered by ignition) and on the same line a link to a picture of the relay, fuse, and circuit breaker.
http://cgi.ebay.com/ebaymotors/PUROL...QQcmdZViewItem
PS about 2/3 down this web page is a pic of the pump in my car:
http://www.corvetteforum.net/classic...e/index5.shtml
At the bottom of the web page is a link to the wiring of the relay (triggered by ignition) and on the same line a link to a picture of the relay, fuse, and circuit breaker.
Last edited by magicv8; 08-11-2007 at 03:16 PM.
#6
Le Mans Master
Thread Starter
Ron,
I'm fooling about in the garage and saw your message. Yes, I have the Edelbrock #9266 (0.320") insulator but I put that on just as a matter of caution three years ago When I dumped the Holley out of frustration. I am sure it has some effect on percolation but I have not tried the carb without it.
You have had the #1406 on for 1-2 seasons previous to this? And it did not give problems? I suspect then that the fuel pump is going bad.
BTW, what ambient temps? Also, I am confused as to where the eight feet of flex line is installed....
I'm fooling about in the garage and saw your message. Yes, I have the Edelbrock #9266 (0.320") insulator but I put that on just as a matter of caution three years ago When I dumped the Holley out of frustration. I am sure it has some effect on percolation but I have not tried the carb without it.
You have had the #1406 on for 1-2 seasons previous to this? And it did not give problems? I suspect then that the fuel pump is going bad.
BTW, what ambient temps? Also, I am confused as to where the eight feet of flex line is installed....
Don't remember offhand if I ran this setup last summer or not, but I have the problem off & on in very hot weather. I'm beginning to suspect as you mention that the fuel pump might be going, gonna run some checks on it and may replace it "just in case", although I hate to start down the "just in case" road.
The insulator on your carb doesn't give you any clearance problems with the hood? Haven't checked mine yet to see how much clearance is left.
Ambient temps in the 90's is where I see problems.
Thanks all for the input, I appreciate it much.
Ron
#7
Le Mans Master
Thread Starter
The one in my car looks like this
http://cgi.ebay.com/ebaymotors/PUROL...QQcmdZViewItem
PS about 2/3 down this web page is a pic of the pump in my car:
http://www.corvetteforum.net/classic...e/index5.shtml
At the bottom of the web page is a link to the wiring of the relay (triggered by ignition) and on the same line a link to a picture of the relay, fuse, and circuit breaker.
http://cgi.ebay.com/ebaymotors/PUROL...QQcmdZViewItem
PS about 2/3 down this web page is a pic of the pump in my car:
http://www.corvetteforum.net/classic...e/index5.shtml
At the bottom of the web page is a link to the wiring of the relay (triggered by ignition) and on the same line a link to a picture of the relay, fuse, and circuit breaker.
Ron
#9
Team Owner
Ron,
With the original setup with a SB hood I had to use a 2" air filter to get hood clearance. Things are fine now (since 2005) with the new paint job and stinger hood. I have driven in weather with humidex readings of 100*F (yes, it does get that hot here) with no problems other than losing 5 lbs of body weight through water loss. Get a NAPA fuel pump and go from there. I always seek the most inexpensive route first.
With the original setup with a SB hood I had to use a 2" air filter to get hood clearance. Things are fine now (since 2005) with the new paint job and stinger hood. I have driven in weather with humidex readings of 100*F (yes, it does get that hot here) with no problems other than losing 5 lbs of body weight through water loss. Get a NAPA fuel pump and go from there. I always seek the most inexpensive route first.
#10
Instructor
Member Since: Dec 2002
Location: Charlotte NC
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I'm running an Edelbrock on a 327 - 300 hp. I had an episode of fuel percolation/vapor lock a couple of months ago. I had a spacer, but had not installed it. After putting in the spacer, there has been no repeat of the vapor locak/fuel percolation problem. I'd recommend getting an insulator/spacer. I'ts a simple installation and can't hurt.
Steve Phillips
Steve Phillips
#11
Le Mans Master
Thread Starter
Ron,
With the original setup with a SB hood I had to use a 2" air filter to get hood clearance. Things are fine now (since 2005) with the new paint job and stinger hood. I have driven in weather with humidex readings of 100*F (yes, it does get that hot here) with no problems other than losing 5 lbs of body weight through water loss. Get a NAPA fuel pump and go from there. I always seek the most inexpensive route first.
With the original setup with a SB hood I had to use a 2" air filter to get hood clearance. Things are fine now (since 2005) with the new paint job and stinger hood. I have driven in weather with humidex readings of 100*F (yes, it does get that hot here) with no problems other than losing 5 lbs of body weight through water loss. Get a NAPA fuel pump and go from there. I always seek the most inexpensive route first.
I'm running an Edelbrock on a 327 - 300 hp. I had an episode of fuel percolation/vapor lock a couple of months ago. I had a spacer, but had not installed it. After putting in the spacer, there has been no repeat of the vapor locak/fuel percolation problem. I'd recommend getting an insulator/spacer. I'ts a simple installation and can't hurt.
Steve Phillips
Steve Phillips
#12
Team Owner
Ron,
Just a last thought for today before I tuck things away (including myself) for this evening. You do have a vented gas cap? Just trying to cover all possibilities. Don't need pressure in that gas tank.
Just a last thought for today before I tuck things away (including myself) for this evening. You do have a vented gas cap? Just trying to cover all possibilities. Don't need pressure in that gas tank.
#13
Le Mans Master
Thread Starter
Thanks for the suggestion, though!!
Ron
#15
Le Mans Master
Thread Starter
#17
Le Mans Master
Thread Starter
Yep, but usually starts at a slower speed. Then, by pumping the accelerator & shooting a little gas in the carb with the accelerator pump I can get it going up to 25-30 before it starts to stall again. This cycle goes on repetitively for 2-3 times before completely running out of fuel, none in the carb bowls.
Then, after waiting 20-30 minutes for some gas, pour some down the throat, keep it running a few seconds by feeding gas, it'll pick up and go until next time.
Happened 2 or 3 times, but has run out as you ask when slowing down for a 30 mph curve after a 8-10 mile drive. Kind of inconvenient . . .
Then, after waiting 20-30 minutes for some gas, pour some down the throat, keep it running a few seconds by feeding gas, it'll pick up and go until next time.
Happened 2 or 3 times, but has run out as you ask when slowing down for a 30 mph curve after a 8-10 mile drive. Kind of inconvenient . . .
#18
Team Owner
Ron,
Get a new fuel pump. I was out today for a show in 85*F heat. My car normally runs at 180*F. Sitting in line to get into the show the temp went up to about 210*F. I have seen this before. But no runnings problems.
Get a new fuel pump. I was out today for a show in 85*F heat. My car normally runs at 180*F. Sitting in line to get into the show the temp went up to about 210*F. I have seen this before. But no runnings problems.
#20
Race Director
Ron you can order the Holley heat shield and it comes with the spacer I would recommend that you install both. This is a classic problem with Holley's and Barry Grant Carbs for that matter. JMO. Dave
You should be able to see the shield in this pic as well as the same phenolic spacer that Paul is using.
Paul BTW is there a reason you are not running the stock drop base filter housing? Dave
You should be able to see the shield in this pic as well as the same phenolic spacer that Paul is using.
Paul BTW is there a reason you are not running the stock drop base filter housing? Dave