Fuel check valve (underneath car)

[MIGHTY 8]

Hello,

Am having again some fuel starvation issues. After 150 road trip yesterday car dies. AAA to the rescue...loaded up on flatbed...arrive at shop...fires right up and I end up driving home another 5 miles to garage as if nothing ever happened!

I have a small fuel pressure gauge inline between carbs which was showing zero psi. Disconnected fuel line and sure enough with battery switch on, no fuel coming out of line.

Whole time I could HEAR AND FEEL electric fuel pump running.(which is about a year old.)

Haven't had opportunity to test the fuel (bad fuel?) and confirm if I can eyeball any contaminants there. Note to self-Will eventually purchase inline clear fuel filter for future sake.

Similar problem last year which was traced to clogged check valve located underneath car near rear axle.

Question is, could it again be the culprit as to I have no idea if when it was replaced if it was just some ancient derelict piece my mechanic pulled out of some used parts bin lying around?
Wanted to ask you all what you can tell me about this check valve.

Seems to be a recurring $1 part causing $500 headaches!!

Thank you,

[majicwrench]

No fuel coming out of line so "bad fuel" isn't an option.

Check valve, who knows?? Ya need to test something, no point guessing.

MOST of the time things like clogged filters/check valves etc are consistant, they don't work/don't work.

What sort of fuel pump?

[MIGHTY 8]

Airtex 5.5-9PSI 12V.
Nothing to write home about....but it works.
Bad fuel could have caused the clog, hence my assumption.
Only thing that separates the moment of fuel starvation and back up and running, is the ride atop the flatbed.

Could that simple tilting up the ramp effect the solution??

Further test drive/analysis will have to wait till next weekend unfortunately.

Thanks for replies

[majicwrench]

Tough to fix things that are working, all the testing will , of course show good. yes, bad fuel can plug stuff, my point, poorly typed in my first response, is that few "plugs" come and go. And few things "plug" so securely that no fuel can get thru.
One thought, after a long drive, if you don't have a fuel tank vent, vacuum will build up in tank to the point that the pump cannot pull out fuel. Once shut down and allowed to sit, this will generally correct itself, and generally will not give you problems on short trips. Worth looking into. Much more likely than something plugging.

[MIGHTY 8]

Magic,

One of the first things I did when the car died and wouldn't restart was to check the gas cap for signs of over pressure.
I have started to always note that pressure every time I pumped gas, to get a feel for what was supposed to be normal.

Sure enough, now that you mention it...unlike when I pumped gas earlier that day of my drive (and pressure seemed normal) when I broke down and checked the gas cap, it was excessively tight!

Suggestions from here on out? Drill a tiny hole in the cap (I believe I read that somewhere?)

Thank you greatly!

[MIGHTY 8]

Just to note...
Googled "drill a hole in your gas cap"

And results ranging from Corvette forums, Vespa forums, to Harley guys talk about solving vacuum under pressure problems by drilling small holes.

"DRILL BABY DRILL!!"


And now that I recall, I did remove my charcoal canister awhile back and surely did cap off the tank vent lines.

Hmmmmmmm.....

[bradartigue]

While you're googling search for Airtex fuel pumps. Probably have as many negative reviews as positive ones. Those cheap electric pumps are worth about a year at best.

[MIGHTY 8]

While you're googling search for Airtex fuel pumps. Probably have as many negative reviews as positive ones. Those cheap electric pumps are worth about a year at best.

Yeah.... I was afraid you would say that. I had to buy it cause it was the only type/brand available at the time.

Any recommendations? I'll give another peek at your (indispensable) IDF pages shortly.

Would like to steer toward the trunk (vertically) mounted type just because of the easier access if/when things do go south.

[MIGHTY 8]

Well,
I'm sitting in the car trying I figure some things out.
Sure enough, with the key on, I can hear and feel the elec. pump run and pressure builds to around 3 PSI. Sure enough, she fires up and runs for awhile then I can see the fuel pressure gauge slowly go to 0 PSI and then it dies.
Let her cool for awhile and a repeat from above. I would periodically remove the gas cap to see if there is a build up of negative pressure, but the cap pressure remains the same. Also, I removed the plug I had put over the return line in the engine bay.
I ordered the Facet elec. pump from IAP and will start by replacing the Airtex brand I currently have. Last time this happened, I was using the Airtex and although I could hear and feel it, replacing the pump resolved the issue.
I hate to throw parts at these problems, but in the case of Facet vs. Airtex, I can see no wrong in replacing the pump.

Any suggestions, please let's have them.

Will report results with new Facet pump by Tuesday.

Thanks!

[RoyBatty]

Hi S8,
I just got finished going thru a similar issue as you seem to be experiencing.
I had installed the idf clones from Auto Ricambi back in December, and had been running them with great success on a normal facet metal cube pump since then. I was using that pump because that's what was in the car when I installed the carbs and I planned to install a different pump were it needed to make the idf's run. But such as it was they ran fine on the facet for the last several months.
In the last couple weeks I noticed I was loosing power at the top of the RPM range, The engine stopped revving as free as it had when I first installed the idf's. This slowly continued to degrade to the point that if I downshifted to pass a slowpoke in 3rd and revved her up thru the range and then went to 4th, the engine flattened out and acted as though she was starved for fuel.
Even after I went into 5th and backed off the power, it took a mile or two of staying off the pedal to allow the float chambers to refill to the point that I could tip back into the power.
I started into the troubleshooting process and found contamination in my fuel supply line and that some of the finest particle had made it past my fuel filter and into the carbs float chambers.
I throughly blew out all passages and jets and such in both carbs and installed a new filter.
I also installed a rotary fuel pump from summit that came with a fuel pressure regulator.
I did my first test drive with this new pump and regulator, after setting the pressure to just above 3psi, and found my problem had not gone away. Knowing from my inspection of the system that there was no more contamination getting thru to block flow, I took the only logical action and bumped the regulator up to an indication of 7 PSI on the indicator between the carbs. This made a bit of a difference but still not totally right. So I again adjusted the regulator to an indication of 10 psi on the fuel psi indicator. The beast is BACK! I was looking for any indication of the needles beling blasted off their seats and flooding, but it never happened.
All I can figure is that either my indicator is WAY inaccurate or the idf clones are not as sensitive to higher fuel psi as the real Webers, or maybe a little of both.
In any event, I drove it for a couple 20 mile test runs and all seems well.
I'll keep you posted and be watching your progress.

[seabeelt]

Funny you mention drilling a hole: .

I was working on the car last summer after replacing the fuel tank and heard a hissing noise. The photo shows a tiny and I do mean tiny hole in the overflow tube to correct for make-up air. The car was missing the vapor canister when I got it and the two way valve in the trunk was disconnected for probably the same issue. Anyway, when I get around to it, I plan on reinstalling a vapor canister and a new valve and then plugging the hole back up. I will replae all of the fule lines while I'm at it just to be on the safe side.

r/

[majicwrench]

IF pump runs and no fuel comes out, and no vacuum in tank, sounds like bad pump. If you really want to make sure, "T" a vacuum gauge into line before pump and see what it reads.

I see soooo many fuel delivery issues on this site w electric fuel pumps, mostly cheapy pumps. The mechanical pumps are pretty dang good, not sure why everyone want to run electric pump, crap wiring etc.

When checking fuel delivery issues in my shop, I "T" pressure/vacuum gauges before and after pump, hang em on the wiper arms, then drive till condition occurs.
Keith

[MIGHTY 8]

Thank you all for your replies.
Would like to report that after installing a Facet electric pump purchased from IAP, it seems to have resolved my car's problems.

Nothing more to say about Airtex pumps at this point other then just they're good at to practice throwing things into the garbage.