It seems this summer has been a tad hotter than usual in the So Cal desert...and my off road Passport (Isuzu) has gotten vapor lock a few times, when it never has before. I have been using a different gas (Sinclair)when I fill up the vehicle when I meet my family/friends. Possible different gasolines could "vaporize" easier? Thanks in advance
Any additive helps stop "vapor lock"?
- Thread starter tenderloin
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Install a check valve on the pressure line.
Fuel injected or carb'd? Our Sinclair station is supplied by shell so I don't think it's the fuel
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Originally Posted By: Chris142
Fuel injected or carb'd? Our Sinclair station is supplied by shell so I don't think it's the fuel
FI from 1998 We meet up and fill our tanks at the Sinclair on Main Street not far from your shop before we head out to the desert/mountain trails (before fire). Just odd the ol' girl would be acting up now.
Fuel injected or carb'd? Our Sinclair station is supplied by shell so I don't think it's the fuel
FI from 1998 We meet up and fill our tanks at the Sinclair on Main Street not far from your shop before we head out to the desert/mountain trails (before fire). Just odd the ol' girl would be acting up now.
We have been using that gas innour cars with no problems. It's shell gas. I don't think a pressurized fuel injected system can vapor lock. Carbs did but the gas was just sitting in the bowl or line
either the fuel line doesn't stay pressurised (find the leak then: pressure regulator, non-return valve in the pump, injector or external) or it's not vapor lock. Could be a temperature sensor acting up aswell
I wouldn't have believed it if I hadn't seen it, but a few years ago a buddy had a mid-90s GM car that was vapor locking during the hot months. However, if he ran non-alcohol gas (probably not available where you live), it would run fine. I suspect his fuel pump pressure was marginal, but I never went out of my way to screw on a pressure gauge to verify this.
A couple years earlier, I set up one of those large-scale water pumps that a local business had bought that was powered by a V-Twin Briggs & Stratton engine (prolly about a 16 horse or so) to drain a flooded clay pit. Of course, the carb sits right between the cylinder jugs and the fuel tank sits on top of the carb. At the time, the temps here were 100+ every day and the pump would run for about 15-20 minutes and stall. The owner couldn't figure out why it would quit and several calls to the tech help at B&S didn't help. Just on a guess, I unbolted the gas tank, moved the tank away from the engine and hooked up a fuel line that I unrolled from a spool. It happened to be about 30 feet and I simply had it on a gravity feed. The engine never quit after that until it would run out of gas.
Vapor lock can be a hard problem to fix and then it just sometimes goes away. (When the temps get cooler, lol)
A couple years earlier, I set up one of those large-scale water pumps that a local business had bought that was powered by a V-Twin Briggs & Stratton engine (prolly about a 16 horse or so) to drain a flooded clay pit. Of course, the carb sits right between the cylinder jugs and the fuel tank sits on top of the carb. At the time, the temps here were 100+ every day and the pump would run for about 15-20 minutes and stall. The owner couldn't figure out why it would quit and several calls to the tech help at B&S didn't help. Just on a guess, I unbolted the gas tank, moved the tank away from the engine and hooked up a fuel line that I unrolled from a spool. It happened to be about 30 feet and I simply had it on a gravity feed. The engine never quit after that until it would run out of gas.
Vapor lock can be a hard problem to fix and then it just sometimes goes away. (When the temps get cooler, lol)
I have a Chrysler industrial flathead 6 mounted to a 4" fire pump, they have always had a history of vapor-locking. Originally the fuel tank was mounted above the engine, I moved it and it helped but didn't cure the problem. Snapping 4 clothespins onto the fuel line eliminated the problem, they work as cooling fins.
I did not think car EFI engines got vapor lock. My brothers boat with EFI has fuel coolers (water cooled).
None. You have a mechanical issue that exhibits symptoms of "vapor lock" which I heard of since 1980's or likely 70's.
A weak fuel pump and a low tank will create vapor lock in hot weather on an EFI engine. Happened to a buddy of mine on the way home from Lost Wages The hot weather BMWs and my Jaguar XJ6 ran The gas lines through the HVAC to prevent it.
I have many comments:
1) Are you sure it is vapour lock? All of the FI vehicles I have ever owned have the fuel pump in the gas tank, therefore the entire fuel line is under pressure during operation and vapor lock will not form easily (or at all). It was in older cars with the fuel pump mounted on the engine that drew fuel from the fuel tank and this caused a pressure drop in the suction line that made conditions ripe for vapour lock. Plus the pump was hot from being mounted on the engine thus exacerbating the issue. Aftermarket FI systems that have an electric pump located midway between the tank and FI system can have issues as well.
2) Absolutely ethanol blended fuels are more susceptible to vapour lock (and a host of other maladies). The RVP (Reid Vapourization Pressure) is generally about 1 psi higher than the seasonally equivalent pure gasoline. It is my understanding (and experience) that many parts of America do not readily offer ethanol free fuel so you may not be able to avoid this type of fuel. However, see point #1, an in-tank mounted electric OE type fuel system really should not vapour lock, even with higher RVP fuel.
3) Did you get caught with a winter blend of fuel? The RVP will be much higher in the winter blend. But I will mention again is it really vapour lock?
Is your fuel pump submersed in the tank or is it an in-line pump mounted along the underbody somewhere. If it is the former, I doubt you have vapour lock, If it is the latter then perhaps.
1) Are you sure it is vapour lock? All of the FI vehicles I have ever owned have the fuel pump in the gas tank, therefore the entire fuel line is under pressure during operation and vapor lock will not form easily (or at all). It was in older cars with the fuel pump mounted on the engine that drew fuel from the fuel tank and this caused a pressure drop in the suction line that made conditions ripe for vapour lock. Plus the pump was hot from being mounted on the engine thus exacerbating the issue. Aftermarket FI systems that have an electric pump located midway between the tank and FI system can have issues as well.
2) Absolutely ethanol blended fuels are more susceptible to vapour lock (and a host of other maladies). The RVP (Reid Vapourization Pressure) is generally about 1 psi higher than the seasonally equivalent pure gasoline. It is my understanding (and experience) that many parts of America do not readily offer ethanol free fuel so you may not be able to avoid this type of fuel. However, see point #1, an in-tank mounted electric OE type fuel system really should not vapour lock, even with higher RVP fuel.
3) Did you get caught with a winter blend of fuel? The RVP will be much higher in the winter blend. But I will mention again is it really vapour lock?
Is your fuel pump submersed in the tank or is it an in-line pump mounted along the underbody somewhere. If it is the former, I doubt you have vapour lock, If it is the latter then perhaps.
Intrigued by your issue I surfed a bit:
http://www.arb.ca.gov/fuels/gasoline/rvp/rvp.htm
California is very strict on their RVP, much more strict than my jurisdiction. Your gasoline, ethanol or not, should have a low enough RVP number as to not be a part of your issue if your fuel system is in good condition.
When do you notice your issue... after stopping for a while... or while running? Stop and go... freeway? Can you provide more information?
http://www.arb.ca.gov/fuels/gasoline/rvp/rvp.htm
California is very strict on their RVP, much more strict than my jurisdiction. Your gasoline, ethanol or not, should have a low enough RVP number as to not be a part of your issue if your fuel system is in good condition.
When do you notice your issue... after stopping for a while... or while running? Stop and go... freeway? Can you provide more information?
My 2000 Jeep Cherokee "vapor locks" on hot days, especially with ethanol gas. 2 catalysts right under the fuel rail always causes it to have a cylinder 3 misfire, or if it gets real toasty under the hood it'll start missing on 2-5 randomly.
I usually just hold the gas pedal to the floor for a few seconds. That seems to help.
And toggle the factory electric fan on
I usually just hold the gas pedal to the floor for a few seconds. That seems to help.
And toggle the factory electric fan on
Originally Posted By: marc1
3) Did you get caught with a winter blend of fuel?
definitely not.its a busy station on main St and is supplied by our local shell supplier
3) Did you get caught with a winter blend of fuel?
definitely not.its a busy station on main St and is supplied by our local shell supplier
It started occurring in the afternoon when the ground/roads seem their hottest Car is hard to start several times and will not idle. Once up to speed all is well. When engine cools or outside temp goes down it runs like new. I believe the fuel pump is in the tank.
Originally Posted By: tenderloin
It started occurring in the afternoon when the ground/roads seem their hottest Car is hard to start several times and will not idle. Once up to speed all is well. When engine cools or outside temp goes down it runs like new. I believe the fuel pump is in the tank.
Is the engine overheating?
It started occurring in the afternoon when the ground/roads seem their hottest Car is hard to start several times and will not idle. Once up to speed all is well. When engine cools or outside temp goes down it runs like new. I believe the fuel pump is in the tank.
Is the engine overheating?
Are you out 4wheeling in this heat?
Chris I was...I know I know
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