Apparent fuel system issue

[MPlayle]

Bruce and I were heading to the Dripping Springs C&C this morning when I had a break-down.

The Mini Van had a sudden loss of power.  No real sputtering, but loss of acceleration and the engine would die if I put the clutch in.  We got to the shoulder of the road at someone's mailbox pull out and did a brief check and I do not seem to be getting fuel to the carb.  I have a clear filter near the carb and it had run dry.  I got down under the back and the electric pump appears to be trying to work.  I can hear the pump whirring and feel the motor spinning when I put my hand on it - just nothing seems to be getting to the carb.  The pump does have a metal pre-filter attached.

I have ordered a motorcycle gravity feed fuel bottle to use to verify things, but it won't get here until Wednesday.

I suspect one of three things: a) clogged filter, b) clogged tank pickup, or c) pump gone bad.

I was fortunate that Bruce was behind me to give me a ride back home to pick up my Crosstrek and trailer to tow the Mini home.  Many thanks to Bruce for his help loading and unloading the Mini.

(Pictures courtesy of Bruce.)

[MiniDave]

oh man, that's too bad.......

[MPlayle]

With the fuel bottle I ordered, I should be able to test the basic line from the pump to the carb (either all at once or in stages) to be sure that is clear and there are no other issues.

Once I know that it becomes determining if the pump is bad, the pre-filter is clogged, or the fuel pickup in the tank is clogged.

I topped up the tank when I met Bruce at our usual spot - a QT gas/store.  We got about 7 miles down the road when it conked out.

Edit:
Here's the confusing part - I drove just over 20 miles at 65 - 70 mph to meet Bruce, topped off the tank with just over 3 gallons, and then drove 7 miles before it died.  Attempts to restart after sitting were unsuccessful.

At least now I have something to do on it as it has been very reliable up until now.

I am going to try to get it up on stands tomorrow and begin syphoning dow the tank for checking the lines at the pump.  Not sure how to check the pump versus the pre-filter that screws directly into the pump.

[MiniDave]

On one of our Texas runs, still well within the Texas borders on the way home Don and I stopped at a fairly sketchy looking gas station and a few miles down the road his Pup died. After sitting a bit it did restart but died again shortly after....it did this several times before we finally made it to a "real" station and I added a bottle of Heet, car ran the rest of the way home with no issues. Give that a try?

[MPlayle]

The place I met Bruce at is a QT (Quick Trip), which is a national chain.  It is generally a busy place.  Bruce uses it regulary and I use it most times we meet for going to area C&C events.

One of the things I noticed is the clear fuel filter I have at the carb is empty - no fuel getting there when the pump seems to be running.  Thus, my suspicion of something at the pump or tank.

[94touring]

Real easy to diagnose with a full tank. Just clamp/pinch the hose from the tank to the pump, undo hose from pump, then undo the the pinched hose and see if anything gravity feeds into a canister. Undo the pre filter to pump and blow a little air backwards and see what all comes out.  Pinch hose and reconnect to pump.  Disconnect hose to carb,un pinch hose, and turn on pump and see if anything flows to a canister. 

[MPlayle]

Today's plan is to get the car up on stands to do pretty much what Dan has suggested.

[MPlayle]

I put the rear of the car up on jack stands to give me more room to get underneath and I tried the suggestion Dan made.  I have gravity flow out of the tank.

I put a spare clear filter on the line from the tank and started to troubleshoot the pump.  I took off its pre-filter and poured out the fuel that was in it then was able to blow air backward through it.  I am still a bit suspect of that, so I made up an adaptor to connect the clear filter directly to the pump.

With that set, I tried to pry off the output line from the pump.  Instead of the hose coming off the pump's nipple, then nipple pulled out of the pump!

I am going to find a replacement pump even though I was able to tap the nipple back into place.  I just don't trust it now.

I did go to the front of the car and found the fuel filter at the carb was now full of fuel where it was empty yesterday.  I am not sure what I did at the back that might have fed fuel to the front.  I disconnected the line into the filter and blew air back through then whole line to the rear and it seems to be clear.

I need to locate an appropriate replacement pump and see when it will get here.

[94touring]

Probably just the pump then. Especially if it's falling apart like that!   You can grab a low psi pump locally, usually it's an Edelbrock 17303.  60-70 bucks last time I bought one.

Edit:  one suggestion I've been telling people with these electric pumps I was reminded about just now in the fuse box thread.   Have it's own dedicated fuse you can pull anytime you need the ignition on to work on something.  I've burnt up a couple pumps on my bus by having the ignition on and the pump running with the engine off. It uses fuel to cool itself and will overheat and die if the fuel isn't actually flowing through it.  They die quicker than you'd expect and will burn your hand if you touch it.

[MPlayle]

Got an replacement pump ordered - expected delivery is May 30.  It is an equivalent to the Mr. Gasket 42S I had in there.

I have an idea on how it suddenly got fuel at the filter at the carb.  I am suspecting the pump packed up and as the engine ran on what was in the float bowl, it put mild suction on the line as it ran our of gas.  The pump has a one-way valve in the nipple that pulled out.  As I was working on things in the rear, I effectively opened the line and the slight vacuum from running out of gas pulled what fuel was in the line into the filter (and possibly the float bowl).

I will still use the motorcycle gravity feed fuel bottle I ordered to do a full line test from the rear to the front of the car to be sure that much is working right.

I had tried one of the locally available Edelbrock pumps when I first converted to an electric pump shortly after getting the car 3.5 years ago.  It was DOA out of the package.  The Edelbrock ones have a lot of bad reviews lately for that very problem - lots of DOA units.  That was why I went with the Mr.Gasket 42S back then.  I have ordered the Jegs equivalent to the 42S and will see how that does.

Nobody local has anything other than the Edelbrock in stock that is the low pressure needed by the SU carbs.  I would have to order it and wait until Thursday or Friday for it to arrive.

[94touring]

Yeah they all kind of suck for quality unfortunately. I went back to mechanical on the bus because it's difficult to swap out electric on it, but have electrical on the mini because it's difficult to swap mechanical on it. I only use an electric pump on the bus to transfer fuel from the aux tank to the main tank, but the pump is easy to access where the aux tank is.

[MiniDave]

I went thru three of the Mr.Gasket pumps before I got one that worked....I've heard Facet pumps (the little square ones) are supposed to be pretty good.

I've had the best luck with the electronic versions of the SU pumps, I put one on my Jag and it ran more than 10 years with no issues.

Facet pump from Moss   https://mossmotors.com/377-420-solid-state-electric-fuel-pump-by-facet

When I was buying these from Victoria British, they were about $150!      https://mossmotors.com/377-255-solid-state-electronic-fuel-pump-by-genuine-su-negative-ground

[cstudep]

I have one of the Facet pumps on my car, it's got to be 15+ years old now I would guess and still works just fine. No idea if the newer ones are as good or not, just like everything else these days.

[bikewiz]

Pegasus Racing has Facet low pressure pumps and they ship quickly.
https://www.pegasusautoracing.com/group.asp?GroupID=FUELPUMPLOW

[MPlayle]

I thought about switching to one of the facet cube pumps.  I decided to stay with the basic model I had for now.

I'm still investigating some aspects of the issue while I wait for parts.

[MPlayle]

I think I found the true nature of the original problem: vacuum lock on the tank.

When I starte my troubleshooting yesterday, I was going to syphon off a buch of the fuel from the tank before trying Dan's suggested tests and changed my mind.  I remembered starting to open the cap, then reclosing it and proceeding to Dan's tests.

The fuel tanks on the lwb Minis (Vans, Pickups, Estates) are not vented.  They require a vented filler cap.  I did a careful inspection of mine and it was not vented (it is now).

I guess I have been lucky until now in that this problem has not happened before in my three and a half years of owning the car.  The cap not having any gasket inside may help explain why I haven't had the problem before.  I guess I managed to get it seated just right when I topped up the tank Sunday when I met Bruce that it fully sealed and when enough vacuum built, the pump could not draw anymore fuel.

[MiniDave]

I remember the vented cap on Buzz leaked like a sieve when we were on our runs in Texas that time......coming out the vent I assume - so watch for that. I remember it took the paint off the side of the car under the filler.....

[MPlayle]

I made just a tiny 1/16 inch hole in the top center of the cap.  It should be just enough to prevent the sort of vacuum lock I suspect was the real problem.  There is a raised center piece inside the cap that I had to also drill the same size hole into so it is vented clear through.

Thinking about it, I may add another tiny hole on the inside for that chamber to drain back out in case any fuel splashes into it.

[MPlayle]

I got an email from Jegs regarding the fuel pump I ordered: it is backordered until 6/27/2025!

I went back to digging online and found a different low pressure pump at O'Reillys the was instock at a local store near me, bought that one, cancelled the Jegs order and will try the Precision brand one from O'Reillys.

I hope to get back to it tomorrow afternoon or Friday.

[MPlayle]

Well, I got the new fuel pump in and working.  It pumps fine into a container at the carb end of the line and seems to stop when the line gets pressurized from the float valve closing.  I do have fuel in the float bowl.

It still won't fire up - just cranks fast.  I do have 12 volts at the coil when the ignition is turned on.  I tried to check the #1 plug for spark, but could not tell for certain.

More troubleshooting to have to take place tomorrow after some morning work meetings.  I got too melted today to do more.

[94touring]

It wasn't that long ago I had my coil die and I suspected the fuel pump.

[MPlayle]

I just tested my coil and inspected the points in the dizzy.  The points are moving and gapped correctly.

The coil measured 2.9 ohms at the primary coil and 34.2K ohms at the secondary.  The coil is the standard "gold" coil available on Mini Spare and is supposed to be 3 ohms primary and around 7K to 8K ohms on the secondary.

The 2.9 is close, but the 34.2K is way above what is supposed to be normal.  It looks like time for a new coil and see what happens next.

[MiniDave]

You may in fact have a bad coil, but a bad coil would not have emptied out the fuel filter .....

[MPlayle]

I am thinking I got hit with both a vacuum lock on the tank keeping the pump from refilling the filter and carb AND the coil going out.

The filter was definitely empty for a while.  It suddenly was full again when I started fiddling with things at the tank.

With the new pump installed and confirmed working (pumping through the whole line and filter by the carb into a container AND when connected to the carb) I was still not starting, which led to checking for spark which has in turn led to the coil seeming bad.

I just got back from some errands that included getting a new coil.  I will try to test, install, and try it for starting the car in a short bit as I still ahve some things to do from the errands.

[MPlayle]

This is being really frustrating.  I pre-tested the new coil and it has 3.3 ohms on the primary and 9.1K ohms on the secondary - right where it is supposed to be.

I put it in the car and no change - still won't start, although the tach jumped to max and back each time I tried to start the car.  I disconnected the signal feed for the tach from the coil and still nothing.

I have a spark plug tester light, so decided to check the quality of the spark from the coil directly to the block.  I get spark, but it may be weak: not bright and very yellow/orange in color.

I tried the same spark test at #1 by going through the cap/rotor out the #1 line through the tester to the block - no spark.  Would that mean it is too weak to go from the rotor to the plug lead?

I pulled the condenser to test it and it seems erratic.

I'm starting to think I may just need to replace points, condenser, rotor, cap, and wires just to cover everything.  Also beginning to wonder whether to convert to electronic.  The distributor is a 59D4 with the blue, sliding points.

None of the local parts outfits have it - all have to order it for basically $20 at any one of the big chains and 1 week delivery time.