She quit....
Thread Starter
Instructor
Joined: Jul 2010
Posts: 103
Likes: 1
She quit....
I wanted to start by thanking everyone for helping me through some of my 'education' my '73 L82 4-spd has been running hot, straight and normal right up to last Saturday when I experienced another unusual incident.....
Because of a prior issue, I installed a clear gas filter in line between the fuel pump and the carb which is turning out to be one of the smarter modifications I've made. When I raised the hood there was no gas in the filter and when I turned it over, you'd see a sputter of gas into the filter but no where near enough to start the engine let alone run it. My initial thought was that my new Holley fuel pump failed me as that is the exact same thing that happened when my last one went. However, three hours and a $160 towing bill later she fired right up, the filter filled and life was good again....
Any ideas what happened and how to correct it?
Jim
- Outside temp was mid 90's, certainly not the hottest we've driven in.
- Engine temp was running around 210, a bit hotter than normal but excessively high.
- Everything running fine until she stumbled, coughed and died at a traffic light.
Because of a prior issue, I installed a clear gas filter in line between the fuel pump and the carb which is turning out to be one of the smarter modifications I've made. When I raised the hood there was no gas in the filter and when I turned it over, you'd see a sputter of gas into the filter but no where near enough to start the engine let alone run it. My initial thought was that my new Holley fuel pump failed me as that is the exact same thing that happened when my last one went. However, three hours and a $160 towing bill later she fired right up, the filter filled and life was good again....
Any ideas what happened and how to correct it?
Jim
Drifting
Joined: Aug 2005
Posts: 1,372
Likes: 4
From: Springfield VA
Well the good thing is you have a place to start, the fuel. I have seen issues like this and when it restarted they did not know what was wrong.
Is the fuel line near anything hot that could cause vapor lock?
Is the fuel pump electric? Check the wiring to make sure its ok? is the fuel pump run off a relay?
I would start the car and let it idle and see if it happens again. When it does then check voltage or open the fuel line to vent it and see what happens. Be careful of course when working with fuel.
Is the fuel line near anything hot that could cause vapor lock?
Is the fuel pump electric? Check the wiring to make sure its ok? is the fuel pump run off a relay?
I would start the car and let it idle and see if it happens again. When it does then check voltage or open the fuel line to vent it and see what happens. Be careful of course when working with fuel.
Thread Starter
Instructor
Joined: Jul 2010
Posts: 103
Likes: 1
Hey, Marlin thanks for replying....
The Holley fuel pump is mechanical and the fuel line runs up past the lower radiator hose. They don't touch but they are close. I didn't think that it would be a problem since the fuel would be coming from the tank and continually flowing past the radiator hose so it wouldn't have time to vaporize. I did feel the fuel line and it was hot to the touch (not hot enough to burn you when you grabbed it but not warm either).
The Holley fuel pump is mechanical and the fuel line runs up past the lower radiator hose. They don't touch but they are close. I didn't think that it would be a problem since the fuel would be coming from the tank and continually flowing past the radiator hose so it wouldn't have time to vaporize. I did feel the fuel line and it was hot to the touch (not hot enough to burn you when you grabbed it but not warm either).
Drifting
Joined: May 2005
Posts: 1,968
Likes: 44
From: East TN
Check all the rubber fuel lines, front and rear, and replace any old ones that may be collapsing. Also, do you have a charcoal canister or vented fuel cap. May have an issue with one of those causing vapor lock. Good luck.
Drifting
Joined: Aug 2005
Posts: 1,372
Likes: 4
From: Springfield VA
Hey, Marlin thanks for replying....
The Holley fuel pump is mechanical and the fuel line runs up past the lower radiator hose. They don't touch but they are close. I didn't think that it would be a problem since the fuel would be coming from the tank and continually flowing past the radiator hose so it wouldn't have time to vaporize. I did feel the fuel line and it was hot to the touch (not hot enough to burn you when you grabbed it but not warm either).
The Holley fuel pump is mechanical and the fuel line runs up past the lower radiator hose. They don't touch but they are close. I didn't think that it would be a problem since the fuel would be coming from the tank and continually flowing past the radiator hose so it wouldn't have time to vaporize. I did feel the fuel line and it was hot to the touch (not hot enough to burn you when you grabbed it but not warm either).
Thread Starter
Instructor
Joined: Jul 2010
Posts: 103
Likes: 1
Thanks Mike....
I was having fuel delivery issues so I replaced everything in the fuel system from the gas cap to the screen on the sending unit, all rubber hoses and the canister over the past couple of months (even dropped the gas tank to clean it, blew out the steal fuel lines and even replaced the rubber lines on the vapor canister). Good news was that it solved those issues...now my Gremlins seemed to have relocated!
Marlin....
It's a one in, one out. Where does the second out line on the factory pump route?
I was having fuel delivery issues so I replaced everything in the fuel system from the gas cap to the screen on the sending unit, all rubber hoses and the canister over the past couple of months (even dropped the gas tank to clean it, blew out the steal fuel lines and even replaced the rubber lines on the vapor canister). Good news was that it solved those issues...now my Gremlins seemed to have relocated!
Marlin....
It's a one in, one out. Where does the second out line on the factory pump route?
Last edited by jtramont; Jul 16, 2012 at 02:43 PM.
Drifting
Joined: Aug 2005
Posts: 1,372
Likes: 4
From: Springfield VA
Thanks Mike....
I was having fuel delivery issues so I replaced everything in the fuel system from the gas cap to the screen on the sending unit, all rubber hoses and the canister over the past couple of months (even dropped the gas tank to clean it, blew out the steal fuel lines and even replaced the rubber lines on the vapor canister). Good news was that it solved those issues...now my Gremlins seemed to have relocated!
Marlin....
It's a one in, one out. Where does the second out line on the factory pump route?
I was having fuel delivery issues so I replaced everything in the fuel system from the gas cap to the screen on the sending unit, all rubber hoses and the canister over the past couple of months (even dropped the gas tank to clean it, blew out the steal fuel lines and even replaced the rubber lines on the vapor canister). Good news was that it solved those issues...now my Gremlins seemed to have relocated!
Marlin....
It's a one in, one out. Where does the second out line on the factory pump route?
Thread Starter
Instructor
Joined: Jul 2010
Posts: 103
Likes: 1
Okay, I am familiar with that line, right now it's capped at the engine but hooked up at the tank (came that way when I bought the car)....Sorry for the really dumb question. I thought that that was a return line, how does that prevent Vapor Lock?
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Drifting
Joined: Aug 2005
Posts: 1,372
Likes: 4
From: Springfield VA
I would get some good heat wrap and try to move the line from the Rad hose or other heat sources. If that does not work then get a good 3 line Fuel Pump and install that to see if it fixs it.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Don't take much to perk/boil gasolines, and ethanol makes it worse, the modern way is with that ~1/4" return line and the typical 3/8 ID hose on the fuel line to the pump, but this hose is a nasty little bastard in that it has to be a MOLDED hose, from the source, due to the nasty kinks it needs take.....
In the dim past and forever, the solution is a rear mounted fuel pump keep pressure on the lines leading forward....nothing over 5 psi, and have done with it.....since these cars were designed, there have been SO many changes to gas formulations thanks to the EPA/green weenies, it's very hard to predict behavior under HOT/high ambient temps, much less your engine cooling capASSity....and other engine internals, as well as headers.....
IF you do a rear electric pump, the wiring must be a specific way, you want that pump to quit if engine stops, oil pressure activated....
BUT be running full bore when cranking/running....
In the dim past and forever, the solution is a rear mounted fuel pump keep pressure on the lines leading forward....nothing over 5 psi, and have done with it.....since these cars were designed, there have been SO many changes to gas formulations thanks to the EPA/green weenies, it's very hard to predict behavior under HOT/high ambient temps, much less your engine cooling capASSity....and other engine internals, as well as headers.....
IF you do a rear electric pump, the wiring must be a specific way, you want that pump to quit if engine stops, oil pressure activated....
BUT be running full bore when cranking/running....
Burning Brakes
Joined: Jul 2006
Posts: 1,047
Likes: 12
From: SoCal
Just a caution that's been posted many times on this forum: Although the clear gas filter you bought lets you see what's going on, they have been known to break. Care to guess what happens when they do (hint: Car-b-que) and how quickly a fiberglass body car can be consumed by fire?
You should give serious thought to getting rid of the clear gas filter. Just my $.02...
You should give serious thought to getting rid of the clear gas filter. Just my $.02...
Melting Slicks
Joined: Mar 2007
Posts: 2,520
Likes: 11
From: Hinckley OH
Couple of thoughts:
If it is vapor lock you can pour a jug of water over the fuel pump and it will recondense the fuel and it will start pumping again. If you can confirm it is vapor lock by doing that, then at least you'll know that you are chasing the right problem.
Is it possible you replaced a vented gas cap with an unvented one? If so, then there could be a vacuum building up in the gas tank that the fuel pump can overcome at the higher RPMs when driving but not at the lower RPMs when stopped. If loosening the gas cap allows it to start pumping again, then that is the likely problem.
If it is vapor lock you can pour a jug of water over the fuel pump and it will recondense the fuel and it will start pumping again. If you can confirm it is vapor lock by doing that, then at least you'll know that you are chasing the right problem.
Is it possible you replaced a vented gas cap with an unvented one? If so, then there could be a vacuum building up in the gas tank that the fuel pump can overcome at the higher RPMs when driving but not at the lower RPMs when stopped. If loosening the gas cap allows it to start pumping again, then that is the likely problem.
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
Just a caution that's been posted many times on this forum: Although the clear gas filter you bought lets you see what's going on, they have been known to break. Care to guess what happens when they do (hint: Car-b-que) and how quickly a fiberglass body car can be consumed by fire?
You should give serious thought to getting rid of the clear gas filter. Just my $.02...
You should give serious thought to getting rid of the clear gas filter. Just my $.02...
totally!
Thread Starter
Instructor
Joined: Jul 2010
Posts: 103
Likes: 1
69 Chevy....you are too funny! If you knew the history I've had with this car over the past 18 months and you realized the temperament, you'd call her She too! 
My 76 Ray...Thanks, I know it's not vacuum in the tank. After She
stopped running, I did open the gas cap to make sure that that wasn't the issue (its a new non-vented cap).
Thanks for the comments on the clear filter....will replace it with a steal one once I nail this Gremlin.
My 76 Ray...Thanks, I know it's not vacuum in the tank. After She
stopped running, I did open the gas cap to make sure that that wasn't the issue (its a new non-vented cap). Thanks for the comments on the clear filter....will replace it with a steal one once I nail this Gremlin.
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
So in your mind, your Vette makes a conscious effort to torment you? Wow that's just crazy.
Advanced
Joined: Apr 2005
Posts: 89
Likes: 5
From: Madison WI
For what it's worth.
I just went back to the original type 3-port fuel pump because of the exact same problem you are having. Vapor lock. I've had my 2-port Holley pump on for over 20 years. Mostly no problem, but when it's (really) hot outside.....
I got one at at local auto parts store. However, as was mentioned in an earlier post, you need to get the "S" formed 3/8" line. Any of the Corvette suppliers, e-bay (where I got mine) will have it. The 1/4" line you can get at any auto parts store. They sell by the foot. Two feet will more than due. It's cheap.
Dale in Badgerland
I just went back to the original type 3-port fuel pump because of the exact same problem you are having. Vapor lock. I've had my 2-port Holley pump on for over 20 years. Mostly no problem, but when it's (really) hot outside.....
I got one at at local auto parts store. However, as was mentioned in an earlier post, you need to get the "S" formed 3/8" line. Any of the Corvette suppliers, e-bay (where I got mine) will have it. The 1/4" line you can get at any auto parts store. They sell by the foot. Two feet will more than due. It's cheap.
Dale in Badgerland