Fuel Tank Vents

[yazuki101]

So I woke up this morning and my 2005 Sport Track (4.0L) would not start, turned over like crazy just no combustion. After I tested the fuel pump fuse and relay, my father (the previous owner) mentioned it did the same thing to him once and to fix it he had to start the engine with the fuel cap off. So I tried removing the fuel cap and starting the truck, and it fired right up. I am wondering if vacuum pressure was building in the tank and had no where to vent, but I cannot find any information about how and where the fuel tank relieves vacuum pressure.

Also, I am not sure if this is related, but anytime I put more than 25-30L of fuel in the tank it has trouble starting, almost like the injectors lose their priming during fueling. Never at any other time, just when I fuel up.

 

[04S-TracJon]

I've heard of fuel caps going bad. I've never had that problem but some mechanics I know said that is a common problem.

 

[swshawaii]

Any dash warning lights or trouble codes? EVAP system, fuel filter, fuel pump or regulator, etc. Many possibilities.

 

[gtyates]

My '05 did the exact same thing last summer. It was the fuel vapor purge valve. It is located in the engine compartment between the battery and the relay box. Basically mine was stuck open so it was constantly venting fumes into the intake, effectively flooding the engine. I could smell a faint gas semll as well. I did have a start-up problem or two in the mornings but my biggest problem was start-ups after fueling. This web site explains the issue: http://www.professionalfleet.com/la...ehicle_will_not_start_after_filling_with_fuel

 

[yazuki101]

Any dash warning lights or trouble codes? EVAP system, fuel filter, fuel pump or regulator, etc. Many possibilities.

I plugged in my OBD-II reader and found the error code: P1233- which I googled and found it was a problem somewhere in the FPDM circuit. I am still trying to pin point where in the circuit the issue is. I removed my FPDM and had a look at the back plate (I read corrosion was a problem with this unit) but the plate looked fine.