Can a leaky gas tank cause hard starting?

Kinja'd!!! "razorbeamteam" (razorbeamteam)
07/01/2019 at 12:40 • Filed to: None

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I’m asking because I’ve gotten conflicting information on this. Normally when I fill up the Rover, I stop the pump before the auto shutoff. Last weekend on my epic roadtrip to Michigan, I was washing the windshield and didn’t realize the pump hit the auto shutoff.

I looked under the car and saw a good amount of fuel spilling from the top of the tank. Mildly concerning obviously, but made me wonder if the non-sealed fuel tank could be causing my hard starting issues.

Basically, when I go to turn the key (on hot or cold starts, but it’s worse when cold) it takes 5-10 seconds of cranking before the engine catches. It then seems to come to life one cylinder at a time and idles horribly until I give a few throttle blips, then its all good. Settles in and idles pretty well.

I’ve been chasing this issue as long as I’ve owned the car, with plenty of work done on the relevant components of the engine. Once the car is started, it runs like a peach. I’ve never considered that the fuel tank wasn’t sealed completely. It would be akin to starting the car with the fuel cap off, but that shouldn’t affect things either.


DISCUSSION (5)


Kinja'd!!! Long_Voyager, Now With More Caravanny Goodness > razorbeamteam
07/01/2019 at 13:01

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It may cause issue as it allows the fuel to run back out of the lines when the vehicle sits. When you go to start it, it has to completely re prime the system before it can run properly. I had this issue with the car when the tank was leaking, it would start fine if it was only off for a few minutes, but overnight it was hard starting.

Try this trick before you start it, cycle the key a few times before starting the engine, this should prime the system before you start the engine and should alleviate your issue until you can get the leak fixed. .


Kinja'd!!! Sovande > razorbeamteam
07/01/2019 at 13:02

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It could be allowing air into the fuel line, maybe? 


Kinja'd!!! RamblinRover Luxury-Yacht > razorbeamteam
07/01/2019 at 13:37

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I think this is actually more likely with a modern car that has a vapor-control system in place. But, in almost an opposite way than you’re thinking*. If the gas tank is pressurized and only reluctantly lets air into the tank, then if you’re leaking it might pull a slight vacuum on parts of the fuel system. Either drawing fuel back through the weak check-valving in the pump or out of the “excess”/overflow loop of the injection system with low-pressure injection. Hmmm.

*a leak in the tank above the fuel level and compromising the integrity of vapor control could also allow fuel to pass back through the fuel pump if the system normally relies on tank pressure “helping” the system to stay primed.


Kinja'd!!! razorbeamteam > Long_Voyager, Now With More Caravanny Goodness
07/01/2019 at 14:29

Kinja'd!!!0

I’ll certainly try it. I think I need to get a pressure gauge on the feed line so I can properly asses whats going on. It could be the regulator as well. Appreciate your input.


Kinja'd!!! Long_Voyager, Now With More Caravanny Goodness > razorbeamteam
07/01/2019 at 16:01

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Get a gauge on the pressure line, I’m sure you’ll see the pressure drop as it sits.