Mt. Antero 2, Jim 0

J

Jim A.

New member
Back in '04 during rmihr I tried mt. Antero (14k+ ft) with my then carb'd Scout. Made it to tree line and that was about it. I had to turn around because the carb didn't like the bouncing and elevation. I ordered a afi kit and installed it earlier this year. This past Saturday, my club went back up mt. Antero. I made it about a thousand feet higher but still died out. This time I think it was a vapor lock. I had to back down that steep trail about 100 ft to a switchback and it fired back up. Then I drove back down the mountain without any other problems.
I purchased the afi system just for mountain trails like this, never expecting a problem. I'm looking for ideas for a fix. I've heard that an in-tank fuel pump May solve the problem, any other solutions?

Thanks,
jim
 
Sorry, posted this in the wrong forum. Should have been in the FI forum. How do I move it?

Thanks,
jim
 
I did antero right after I started in FI and had no problem. Bill thebert led the trip.

Even went with a few others down to mt blanca for a 2 day trip on the way home.

I did see a guy on antero with a Holley system with tank vent problems.
Did you think to remove the cap to check for vacuum or pressure built up in the tank.
I don't think an in tank pump would make any difference. You May have vapor lock at altitude tho. It is normally caused by excess heat around the steel fuel lines and the TBI.

Verify the path of your lines and sources of heat. Mainly the exhaust.

My 454 pace arrow tow rig was the only thing I had vapor lock and that was heading over the pass on the way home from rmihr.
I had an old Holley TBI system and it didn't like the wot 30mph climb up the hills! Built up too much heat and would boil the fuel in the lines.
Had to dump water on the TBI and lines to get fuel back to the throttle body.
 
Thanks bill. This May be a gremlin that I hunt down for some time. I checked my fuel lines and the routing should be ok. I went to a junkyard to look for some hood vents off of anything to get rid of some under hood heat and one of the owners had a suggestion I wanted to run past the FI guru's here. He used a tranny cooler from a late 90's grand cherokee (about 4x6) to help cool the fuel. He ran a fuel line from the tank to the cooler near the grill back to the electric pump which helped with his problems. I asked about winter driving and he didn't mention any problems.

Sound plausible?

Thanks,
jim
 
The winter will only affect it if you get moisture in the fuel. Then it will freeze.

But that's a lot more connections and hoses to worry about too.
Use good lines for the runs.
 
Hi jim,

vapor lock generally occurs in low pressure areas of the fuel system. This is because the temperature where the fuel vaporizes is a function of the pressure.

With an external fuel pump, the hose from the pump into the tank is vacuum. I did an efi conversion for an oem with a rail mounted pump. During vapor lock testing, we instrumented the pick up line for temperature and pressure. We also installed clear tubing and made a video of the pick up line.

In this case, the bubbles causing vapor lock could be seen forming in the pick up line. Although the fuel temperature was reasonable, the temperature and pressure combination in the pick up tube were in the vapor region of a fuel phase change chart.

The problem was resolved with an in-tank, immersed pump. No pick-up tube, no low-pressure/vacuum.

Since the fuel between the pump and fuel injectors is pressurized, there should be less risk of vapor lock in this region than on a stock Scout with the engine mounted fuel pump and a carb with an un-pressurized bowl. So stock routing for fuel lines should work.

Although an in-tank pump is more resistant to vapor lock, that does not mean it will always happen. I am very interested to hear how many folks have issues, and under what conditions (altitude, temperature, etc) with the external pumps common in conversion kits.

I had vapor lock problems on my carb equipped Scout. I put an electric pump back near the tank, and although the situation improved, still got vapor lock on long, hot, high altitude climbs (sunny August afternoon at 12,000 feet in co).

I know the issue was in the pick-up tube because I disconnected the fuel line under the truck with the pump running and got no fuel. Ran fine after it cooled down.
 
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