Car running rich, fuel tank gurgling

[Mstng93SSP]

I went to a cruise this afternoon with my 1993 coupe with a 331 stroker. I filled my gas tank and the handle kept clicking off as if it is full, but it wasn't. After getting it full I drove to the cruise with no issues (about 12 miles). Upon returning home the car was running "burn your eyes" rich and when I parked it I could hear the fuel tank make a noise like a flushing toilet. It did this three times. Would a blocked/clogged tank vent cause these issues including the running rich?

Thanks

Chris

 

[Monkeybutt2000]

Drive it then remove gas cap. If it makes the whooshing noise you have an issue.

 

[General karthief]

Purge tank and solenoid still there?

 

[Noobz347]

The filling portion of your story makes me think about checking the vent line to make sure it's clear from end to end.

The rest of the story makes me want to ask what fuel pump and pickup you have in the tank. If my suspicions are correct then I have a theory:


Your 255L pump is making lots of bubbles when the return line is 'gushing' unused fuel. The closed-off vent line is exasperating the issue.

Somewhere on this site, there is a thread and video about this. Maybe one of the others will remember where it is?

 

[Mstng93SSP]

Purge tank and solenoid still there?

Yes.

 

[Mstng93SSP]

I agree @Noobz347 I think I need to make sure that vent lines are clear and change the tank vent.

 

[Noobz347]

There also exists a new style of pickup that puts the return down into the lowest portion of the fuel tank so that it doesn't make bubbles and excessive vapor.

Somebody will hopefully pop up with a link to what I'm referring to.


Alternatively, I suppose you could add some flex hose to extend the return line to a lower portion of the tank.

 

[Mstng93SSP]

I run the dame pump in 3 of my foxes. Never had an issue with the pump before but you never know, could be.

 

[Noobz347]

I run the dame pump in 3 of my foxes. Never had an issue with the pump before but you never know, could be.

I have not had the issue either. I run a 255L high-pressure. I mention it because I've seen it come up before for others.

It's also something I intend to swap out the next time I have the tank down for some reason.

 

[Noobz347]

OH hey! I found the thread with the video I was thinking about:

Thoughts On Fuel Pump Cavitation

View: https://www.youtube.com/watch?v=Ium8jf4Jm04 IMO this video seems to exaggerate what really happens. Since when does 100% of the fuel get returned back to the tank? Has anyone with a 255lph fuel pump experienced unusually high pressure at the fuel rail caused by cavitation?

stangnet.com

 

[AeroCoupe]

Just reworked the whole fuel system on my Coupe and have that video and another one in the first post.

Fuel - Fuel Pump Rewire, New Fuel Lines, and Installation of New Fuel Pump Hanger with AN6 Connections

So I wired in a secondary relay a long time ago when I switched to a Walbro GSS340 255 lph pump but it was pretty much all on the stock wiring. I have finally started the laundry list of things that need to be addressed on the Coupe and upgrading the wiring on the pump is at the top of the list...

stangnet.com

 

[rednotch]

Tanks not venting.. Besides the vales and evap selenoids, check to make sure the canister isn't flooded with fuel. Pretty rare on those cars with it up front in the engine bay but has happened before.

 

[Mstng93SSP]

Ok. Will check it out. Thanks