Ron Miller

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?

magicv8

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.

Ron Miller

Thanks Magic, I'll keep that in mind. What pump did you use, and where did you power it from?

Paul L

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....

magicv8

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.

Ron Miller

I can see where you'd be confused Paul, I've corrected my stupid original entry. I've got a SS braided flex line from the fuel pump to the Edelbrock filter, and then about 8 inches of solid line (same as yours) from the filter to the carb.

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

Ron Miller

Thanks for the info and pictures, Magic. I may go this route if all else fails!!

Ron

wmf62

i suggest you try the carb spacer block, it should help against percolation.
Bill

Paul L

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.

soppeng

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

Ron Miller

Both good advice, I think!! Appreciate it much, believe I'll try the spacer first, then go for the replacement fuel pump if I continue to have problems.

Paul L

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.

Ron Miller

Yep, sure do Paul. Already checked that, but thanks. I also replaced the flex line going to the fuel pump from the steel line (haven't replaced the flex line at the fuel tank yet, gotta do that) and had good flow from the line when I pulled it off. But, can't always go by that, either.

Thanks for the suggestion, though!!

Ron

Matt Gruber

ron
what is the idle speed?
can u raise it? by 50-100%?
works with engine fan only.
keeps everything cooler-nice breeze under hood.

Ron Miller

Usually notice the problem at slower speeds, but have had it even at 30-35 mph, maybe faster. Which leads me to suspicion of fuel pump perhaps contributing to the problem . . . . .

Matt Gruber

it stalls at 30 mph?

Ron Miller

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 . . .

Paul L

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.

Ron Miller

I believe you're right, Paul. I'm gonna spring for the carb spacer and a new fuel pump, too. Thanks!!

By the way, hope your passing gear is still working out OK!!!

Ron

Hitch

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