LR3 Engine Stall, Vapor Lock

[JAK]

On our last SCLR trip to Death Valley, two out of four LR3s had engine stalls at 9200 feet then again at 4200 feet. The climb to 9200 feet was perhaps 2 hours worth of trail time. The climb to 4200 was heading over to Panimant Valley with about 1/2 tank of gas each. The smell of gas was prevalent. Temperatures were moderate, 75-80F. All four LR3s gassed up at the same station in Olancha. Speaking with other members in our club, there are at least two others have had stalling issues on other trails at varying altitudes. Not very repeatable unfortunately. A few common threads would be partial tanks and trail runs where tanks would slosh. My faultmate does not indicate any faults with the the ECM or EVAP system.

A search on the Google has not resulted in much. The conversation on SCLR can be found here, http://www.sclr.org/roverboard/20-t...gine-stalls-in-death-valley.html?limitstart=0

Any insight or help would be appreciated.

Thanks,

Jeremy

 

[Scott Brady]

Almost no chance it is vapor lock. When was the last time your fuel filter was changed.

Does the vehicle restart immediately? Does it stall while under power, or at low RPMS under a load?

 

[JAK]

Fuel filter was a few thousand mile ago at 90k. Here is the strange bit. While going up the grade into Panimant the other LR3, two vehicles behind me, gets on the radio and says that he has a problem an that the engine stalled. As soon as he says the word stalled, mine stalled. The stall was on the grade pulling about 3500 rpm. Attempting to restart resulted in the engine stalling at idle. A second restart with throttle down resulted in revs to 3000 rpm with no stall. Shifted into drive and stalled. Switched to low range 1. Restarted and kept the revs high until I could pull off to the side of the road. Opened the hood and the smell of gas was bad enough for me to look for a fuel leak. It smelled exactly like flooding my old Holly four barrels. The smell was also pronounced from the rear of the truck. I kept my hand on the extinguisher just in case. I let her sit for about ten minutes and tried again. She never stalled again for the remaining two much hotter days. Repeated the same climb out of Death Valley both into Nevada and back to 395 with no problems.

I'll look into changing the filter again as that is simple thing to do. Thanks Scott.

 

[Scott Brady]

That sure seems like fuel being pushed from an overflow on the evap system. The pressure increase could be pushing the fuel into the evap and then filling it up. Once full, those evap systems dump into the motor, causing them to sputter and stall. They will run at the higher RPMS because the engine is able to burn off the excess.

Were the trucks full of fuel (or close to full) at the time?

I am not certain this is the case, but sure seems like it. . .

 

[nwoods]

This exact thing happened to me twice in my LR3, once in Big Bear (6,000 feet), and once at Coyote Flats (8,000 feet, maybe higher?). The smell, the symptoms, everything. I think I wrote about it on LRRforums...in 2006 or 2007. The dealer was stumped. The problem "self cleared" after a few minutes wait (while something reached equilibrium?), and the problem did not reoccur on either trip. I had been higher plenty of times both before and after without issue.

 

[JAK]

That sure seems like fuel being pushed from an overflow on the evap system. The pressure increase could be pushing the fuel into the evap and then filling it up. Once full, those evap systems dump into the motor, causing them to sputter and stall. They will run at the higher RPMS because the engine is able to burn off the excess.

Were the trucks full of fuel (or close to full) at the time?

I am not certain this is the case, but sure seems like it. . .

Both tanks, half full.

 

[Scott Brady]

Both tanks, half full.

I am still reasonably convinced it is an evap canister / altitude / pressure issue, especially since multiple vehicles have experienced it and none resulting in a fault code or failure to start.

It might be worth checking the pressure in the tank the next time you gain some serious altitude. Just pull over and unscrew the cap - listen for the big whoosh.

 

[JAK]

Actually did that at 9200 feet, nothing spectacular. I thought that would actually solve the problem until it happened again at 4200 feet. One of the other guys in the club just replaced the canister. He will be going out again soon. Hopefully it solves his problem.

Thanks for the feedback.

 

[long dong silver]

Actually did that at 9200 feet, nothing spectacular. I thought that would actually solve the problem until it happened again at 4200 feet. One of the other guys in the club just replaced the canister. He will be going out again soon. Hopefully it solves his problem.

Thanks for the feedback.

Some old EFI systems around the mid to late 80s would set their atmospheric pressure value by measuring the manifold pressure just before vehicle start up. A 6000ft climb would result in a very rich running vehicle until the engine is killed and reset.



This does not explain why a vehicle made in the 21st century stalls during climbs, more of an anecdote.

 

[roverbuild]

Throttle Body!

 

[long dong silver]

Throttle Body!

yup, and even the last of those would reset atmospheric pressure on the fly at WOT.

how long did it have to sit before restarting?

Also, its been said but there is no way it is vapor lock. The fuel is pressurized from the tank forward and just can't switch to vapor in the lines under those conditions.

 

[JAK]

We let the truck sit for about 10 minutes. Some updates from others in the club. Apparently this is a common undiscussed issue until now. Another two 2006 LR3s have reported the smell of fuel, the last being this weekend on the way to the AZ, Expo. No stall but a lot of vapor smell.

Common factors so far are, high mileage >90k and high altitude. One of the 2006 LR3s has had its vapor canister replaced recently. We are waiting to see if there is a recurrence of the issue. I will be replacing the canister soon.

 

[nwoods]

My pre-production 2004-and-ahalf LR3 had relatively low miles on my first occurance, maybe 20-30k miles?

 

[JAK]

My pre-production 2004-and-ahalf LR3 had relatively low miles on my first occurance, maybe 20-30k miles?

Wasn't yours a V6?

 

[nwoods]

Yes, but the fuel delivery system is the same.