Hi, my apologies as I know this topic comes up often, but I can't seem to find a solution. I recently purchased an LR3 and I have been trying to get it ready for a 1500 mile trip to Florida in a few weeks. It does not show any engine or evap related codes, but it is very difficult to fuel up. It takes ≈15 min to go from 1/4 tank. It also has suction in the fuel tank particularly at low speeds when the engine is running at high vacuum. I believe this is due to the purge valve being open. I purchased the GAP tool and I can see that shortly after start up the purge valve opens to about 35% and stays always in that position. It was my understanding that the purge valve opens "periodically" but I have not seen a definition of what that period is other than when needed. After reading the attached documentation, I am beginning to wonder if I have a bad DMTL pump. But with no codes showing, I don't want to just start throwing parts at this thing. Is it possible the normally open atmospheric vent is stuck closed and causing these symptoms? Does anyone know if I can test the DMTL pump? I looked through the GAP menus, but didn't find a test, but I am still familiarizing myself with it. Any other thoughts on what could be causing these problems? I should mention, that I also read that one of the vent lines could be pinched if the fuel tank was removed and put back in place. This did happen by the previous owner, but I could not find anywhere that it appeared to have a pinched or kinked line.

Thanks!
Benjamin

 

Did you try pulling the evap system fuse? Not sure if the pump has a relay, could look and try that? But basically if you kill power to the evap system you could probably determine the issue. As far as I know the solenoid valve for evap, located behind the engine, should open and then close after startup. So if its staying open, you are right that engine vacuum is causing the suction. And my killing power to the pump, you an be certain of that. Really surprised no code tho.

 

@DakotaTravler thanks for the input. I am fairly certain the suction is from engine vacuum. I tested by removing the line and plugging the port on the intake. In doing that, the suction appeared to have gone away. I thought this pointed to a stuck purge valve so I replaced it. However, the behavior persisted. This is when I got the GAP tool and can see the solenoid is at about 35% PWM. So I think the purge valve itself is functioning as expected. Though I am not sure how often it should be open. But it seems that the EVAP system shares a vent with the DMTL pump for when the purge valve is open, based on this line from the document.

Though it seems this valve is supposed to be an NO valve so I am not sure it could fail in a closed position? I will probably replace the DMTL pump anyway, I just was hoping to avoid throwing money at it if I could verify the part functionality first.

Cheers,
Benjamin

 

I know this is sort of off topic but can anyone help me understand where the purge valve is? It seems like it is not on top of the engine but behind the top part of the engine close to the firewall? If it’s back there, it will certainly not be east for me to reach / replace.