fuel issues 2006 LX470 (1 Viewer)

[kklaus121]

I have a 2006 LX470 that I purchased a little over 3 months ago. When hot out and driving quite a bit it would be hard starting, just like a vapor lock, until it cooled down then starts fine.

Also I get a fuel vapor/alcohol odor when it is hot out as well, and this odor comes from underneath the vehicle near the charcoal canister or filler tube.

Problem got to the point where the car would stall in traffic. I replaced the fuel pump as fuel pressure when hot was 32psi, and 38 when cool. New pump measured at 40psi according to my mechanic. Still get the occasional hot start issue when temperatures are hot, but not as bad and no stalling.

I have checked the fuel lines that run near the exhaust and don't think that is casing the problem.

replaced fuel cap, dealer performed evap check...everything fine.

Based on recommendations I am looking toward the fuel pressure regulator. I would like to put a mechanical fuel pressure gauge connected in on the front banjo bolt, drivers side closest to radiator, on the fuel rail. This way I can observe actual fuel pressure in the rail under varying conditions.
Does anybody have the size specifications on this bolt? The fuel rail looks aluminum to me so I don't want to mess it up with the wrong bolt.

 

[kklaus121]

wire routing through the firewall

On this 2006 LX I have figured out how to put the fuel pressure gauge on there and have decided to go with a longer term solution and run the electric gauge to the cab. Any recommendations on where/how to route the wires through the firewall?


All of this is in an effort to solve a hot start/vapor lock type issue I have when it is really hot. I want to monitor the fuel pressure in the fuel rail to observe what is going on when this happens and unfortunately it may be next summer before it happens again.

I have replaced the fuel pump, helped with the problem. Replaced the fuel cap. no difference. Had the dealership perform EVAP check as I suspected the charcoal/evap cansiter, checked out fine of course.

When I pull the fuel line off the fuel filter I get quite a bit of vapor that comes out along with liquid fuel. Not sure if this is "normal" but seems odd to me.

Looking at the fuel pressure regulator and pulsation dapner next. Could also be a clogged vent or something like that.

Any suggestions?

 

[kklaus121]

I finally got the fuel gauge installed and have included some pics. Pressure is running a solid 42psi under normal driving and bumps to 44psi when I get on it. Definitely as it should be. Looks like I will have a good amount of time to baseline the fuel pressure through the winter here in CO. When the temperature gets hot again in June I will see if the pressure changes and that may help me solve the vapor lock type problem.

 

[Abalonehunter]

I finally got the fuel gauge installed and have included some pics. Pressure is running a solid 42psi under normal driving and bumps to 44psi when I get on it. Definitely as it should be. Looks like I will have a good amount of time to baseline the fuel pressure through the winter here in CO. When the temperature gets hot again in June I will see if the pressure changes and that may help me solve the vapor lock type problem.
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Hi, I realize this is a post from way back, but did you ever figure out the problem? Same thing has been going on with a family members 2006 LX470 as well.

 

[Escape Artist]

The VVTI models have a proclivity towards vapor lock. There’s really nothing that can be done. Change all the fuel pumps and fuel filters and regulators and wrap the fuel lines and heat shield that you want. If you live in a hot climate, these trucks are not suited to that. Just something you have to learn to live with.