Original problem:

1993 Civic, 1.5, standard transmission would bog, stumble, stutter, stall, and recover when the fuel tank was nearing ¼ on the gauge. Problem was first noted when exiting from the freeway, on a hot day (temp at near 100ºF), stopping, and then shifting away from a stop. If the car sat still, it would recover. This led me to believe that a fuel sloshing, contamination, or loose baffle in the tank was to blame.

Replaced: Fuel filter under the hood.
Cleaned: PCV and hose
Cleaned: EACV
Installed: 1 bottle Techron Fuel Injector cleaner

There was no help when replacing/cleaning the above components.

Tried through 2 tanks of fuel, problem recurred when level fell below ½ slightly, and worsened as the tank level reached ¼.


Fix as found is below:

I have found the definitive fix for the problem of bogging/stalling when the fuel level reaches below somewhere under ½ to ¼ of a tank-full of gasoline. The fuel pick-up screen, or in tank fuel filter had detached from the fuel pump. The slip fit of the plastic components would not adequately hold the filter in place, so I used an epoxy called ‘tank repair’, which is two-part, to adhere the plastic elbows/fittings used for the filter to pump pickup. The car now runs down to 1/32 of a tank with no problems.

My theory: air bubbles from sloshing and low fuel could get into the orifice for the fuel pick-up and cause the sputtering/bogging/stalling conditions. The bubbles are more pronounced and closer to the pickup when the fuel level is low. Even with the in-tank baffle in place and secure, the small bubbles in the fuel are picked up by the pump inlet. The fuel filter, with its very small mesh screen, acts as a sieve to keep the bubbles out of the pick-up tube and therefore out of the fuel circuit, which of course includes the injectors. Air bubbles are simply too big to make it past the screen.

Side note: use epoxy very sparingly, as any dislodged would find itself in the pump and it dries as hard as stone. A very small bit will hold the plastic elbow bits together. I first cleaned them with “Acryli-Clean” that I get at a body shop supply, but Acetone or IPA would suffice here, and then scuffed the mating surfaces very lightly with sandpaper to offer some mechanical bite for the adhesive mentioned above.

Thanks for reading, and special thanks to Ron J for sticking this out with me.

 

Great info, thanks for posting your solution. With all the threads like "help my engine died," it's nice to see a solution. Good find!

 

Thanks for the kind words. I agree, it is nice to see a solution as a follow through. I must credit "mundy5" for giving me the idea to post it with 'problem solved' in the heading. It must have garnered some attention. Another thank you goes to Ron J whose cool head and monitoring of my problem helped me think through it all to the solution. It really helps having such a logical and patient person to bounce things off of, and this list is lucky to have him aboard.

I have been on many other lists, including one for older Mercedes roadsters (talk about needing help!), Jaguar convertibles, BMW e30 series, and even a Lexus IS300 recently. I can tell you that every list has its frequent posters who are simply there to help and they do it selflessly. I hope that this list treats the ones on here with the respect that they deserve, including the moderators and administrators. It is a lonely world when all alone in the garage with an intermittent problem...

Ed Fisher
Dallas, Tx

 

congrats on the fix. i agree, it's nice to see a thread where the problem was solved. There's so many threads on here where people ask questions, we help, and they never tell us if they got it fixed or not.