intermittent fuel pump operation and no start

[todd mann]

This has been going on for serveral months. This car is NOT a daily driver and always sits in garage. yesterday day my 91 honda prelude started after a prolonged period of no-start. Today, i dont hear the fuel pump and it wont start (obviously). I have power to the trunk (yellow) pump wiring confirmed with a multimeter. This is a brand new fuel pump and as i said, it has operated just fine since install and yesterday. but today and last week, it does not make any noise and i cannot start the car.

Some things i’m not sure if related : I moved the battery negative ground a while ago. i moved it because I was looking for bad grounds and it went to a bracket below the battery collocated with a couple connection “boxes” – one i believe has to do with the condensor fan. the other, no idea. I thought it would be a better location (cleaner and more metal) to the front structural member under the car. I dont notice problems from this other than, my oem negative wire had two ground locations and now i only have one. Not sure if this is an issue or not.

I HAD issues with the condensor fan relay clicking (continuously) and totally random starting of the fan (when i drop something in the garage and the car hasnt even been driven all day!). I checked the controller box for burnt/bad soldering and saw no obvious issues, I changed the relay (under hood fuse box) and since have not witnessed this issue again since (a few days). maybe fixed?

A while ago I installed a “kill switch” by splitting the fuel pump wire in the trunk and putting in a toggle switch routed to a hidden spot in front. i have since removed this due to this fuel pump problem that keeps coming back. the kill switch is no longer there and i have confirmed i am getting power through the remade connection. Not sure if tugging wires as i installed and uninstalled this could have caused a weak spot? again, i am reading power to the wire from the battery when i turn key to run.

I believe i may have had air in the fuel lines due to install of pump, new fuel filter, and other diagnostics, but yesterday the car ran and i drove it great so now im just not sure. im having all kinds of trouble opening the banjo bolt due to my filter turning and the mount having a bent portion which will not allow me to turn the bolts. So doing fuel pressure tests has been nearly impossible for me to do. i’m just listening for the pump and i cant hear it.

So having said all that, I am wondering: is this 1. a fuel pump problem caused by an electrical fault such as a bad ground, damaged wire, or maybe a loose pump connection at the pump (i’ve tried wiggling this), 2. Air in my fuel lines that continues to pop up and intermittently cause the car not to start (and i just cant hear the pump, because i keep trying to start the car (it is a very quiet pump). Or WHAT? I’m at my wits end and about to push this car in the street.

Also, the car has a new battery, new alternator, engine runs great (when it starts) …. its a b21a1.

Thanks ETCG.

Topic

[Sam Snow]

I had an intermittent fuel pump on my 1995 Ford Explorer, it would only happen when starting never while running. Replaced the pump (junk yard) and everything was ok for about three weeks then it started doing it again! I connected the fuel pump directly to 12 volts on & off multiple times trying to get it to fail thinking maybe it had a bad spot in the motor, I also let it run in a bucket of fuel for an hour and switch it on & off no problem found. I did the same thing to the original pump and again no problem found they both worked perfectly! I then checked the fuel pump relay with a multi-meter for continuity and voltage, all was good. I then remembered that I had purchased a relay tester years ago but never needed to use it. So for shits and giggles I placed the relay in the tester and BAM! The tester indicated the relay was bad! Even though putting the bad relay back in the truck it worked! So I tested it again, and again the relay tester said the relay was bad. At this point I thought the tester was bad until I tested a new relay, the tester said the new relay was GOOD! Popped in the new relay and the truck has been working fine ever since, it’s been two years and running! Hope this helps you, I know I’ve learned a valuable lesson regarding relays.

[todd mann]

Sam Snow,
Thanks. You led me to the problem. in a roundabout way. Most systems on my car have a dedicated relay. I didn’t see one for the fuel pump on the drawings. I could not see the forest through the trees as the fuel pump relay is in the main relay. I pulled the main relay, resoldered 3 bad connections and viola! Now on to the next emergency (which is brakes!)

Thank you!
Todd

[Sam Snow]

That’s awesome! Glad you found the problem, what a great feeling, Right!
I share what I know.

[Author]

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