Rep Power: 0

So this should be simple enough but no help at the dealership parts dept. I have diagnoised a failed fuel pump on my 2002 Civic EX and would like to just replace the whole assembly. I believe this may resolve my gauge issues as well. I called around and the dealership shows 2 different pumps for that model (Yachiyo and Kautex). They ran the VIN with no luck and told me to pull the pump out and look for indentification as to which pump I need. So I pulled it out and I do not find anything showing me which pump I need. Will either pump work? What is the difference? I need to get this figured out because if I order online ($100 cheaper), these places say they have a no return policy on pumps. HELP!!!

 
Rep Power: 517

I see the same choices for the pump assembly and no clarification for why.

Pumps are awful rare to go bad, these cars aren't like GMs. What exactly did you diagnose? What problem does it have?
Relay problems are more common than real pump problems.

What is the issue with the gauge?

 
Rep Power: 0

No sound from the pump before starting. Test light on 2 wires to the relay showed hot when ignition is turned on. Relay is "clicking" when ignition is turned on. Test light on 2 wires (I think yellow/green and yellow/brown although I would need to double check that) at the pump showed hot with ignition. Fuel gauge inaccurate, not showing full when full and seems to be showing less near empty. Any other way to completely rule out fuel pump? I had the guys at Manchester Honda tell me the same thing about pumps never breaking down.

 
Rep Power: 517

Prove it is not the pump when it acts up. If the pump has power and ground, and it does not run, the pump is most likely bad. If power or ground are missing when it acts up, then it ain't the pump.


Is the pump DEAD all the time now? Car won't run at all?


You say you connected a test light to 2 wires at the relays......

Well, there are multiple relays back there, and each one should have a minimum of 4 wires each. I have no clue what you were doing, or if it would have made sense to me at the time.

The FP relay (PGMFI Main relay #2) has yellow/black and green/yellow, for the electromagnetic coil, and yel/blk and yel/grn are the contacts of the relay.

Yel/grn should be powered up when the relay clicks ON, this wire runs the pump. It will light the test light when the pump should be running (test light clipped to a ground and probe touching the wire terminal).

So stuff your test light into that one and wait for the pump to not run.... If the light is lit up, the relay is still doing its job and the pump is dead (or wiring problem between the relay and the pump....I have seen rodents eat the wires too!). If the light isn't lit, the relay isn't doing its job. More checks to figure out why, if necessary.

Main relay #1 has to operate before relay #2 can operate.


Those relays are dirt cheap compared to the price of a pump, and far more likely to be the issue..


Here's another thought: The ground for the pump and the sending unit are both attached to the beam under the front edge of the passengers front seat. Make sure that is tight and clean.




Not sure what to say about the gauge.
The PCM data could be read to see what it sees as far as a fuel level (MAYBE).
You could do a self check on the gauges. You could ohm test the sending unit.

The PCM has a strategy for keeping the fuel gauge from bouncing all over, and for refueling situations. This is C&P from a Honda service news article: "If you refuel the vehicle with the ignition switch
turned to ON (II), the fuel gauge CPU is in the
%u201Cdrive mode.%u201D In this mode, the fuel gauge needle
movement is dampened by raising the needle one
graduation every 60 seconds. In the %u201Cdrive mode,%u201D
the fuel gauge can take 20 minutes or longer to
read FULL."
EDIT:I have no idea why those %things are in there.

There is another mention of the low fuel light can come on with 5 gallons remaining in the tank, due to fuel slosh.

The fuel level sensor is probably available separate if necessary (I found instructions to replace it but I can't find it in the parts catalog!!)

There is another service news article talking about charting the gauge, by draining the tank, and adding 2 gallons of fuel at a time, and making a chart for each 2 gallon point on the gauge.

I don't recall ever needing to replace the sending unit either.

 
Rep Power: 0

Lots of good information. Yes, the car won't start and the pump is dead all the time as far as I can tell (no sound... nothing). I did test at the PGMFI Main relay #2 shown in my service manuel. This is a blue relay and it also clicks when ignition is turned on. I will check a few things that you mentioned and will post soon. Thanks!

 
Rep Power: 517

More ideas...

Ok, remove the FP relay. Ohm test between the pump feed wire (yel/grn) at the relay and a ground. Open circuit? Or is there an ohm reading like 2 ohms? (no idea what a real reading would be, probably under 10 ohms though).


Is power and ground available at the tank unit connector?

Have someone cycle the key or crank the engine, or just power up the pump by jumpering the pins at the relay, whatever......Bang on the bottom of the tank with a 2x4 or something. Does the pump run now?

 
Rep Power: 0

OK so... Yellow/green that plugs into the pump is hot every time (tested many times) with ignition "on" using a test light. Relay "ticks" and it's hot after a few seconds relay "ticks" and yellow/green is off as it should be I believe. I plugged into pump several times and only twice did the pump turn on briefly. All the rest of the time, no sound from the pump. I do have the pump assembly out of the tank. Now I'm thinking it may not actually be the mechanical part of the pump but maybe the wires that feed the pump (electrical short somewhere). I'm still thinking replacing the whole assembly. I don't want any more headaches down the road. Have any other feedback?

 
Rep Power: 0

Sure enough, the problem was a short within the pump assembly. I monkey rigged some wires to run from the battery directly to the pump and it ran fine. So I disassembled the pump assembly and reassembled making sure everything was tight. Dropped it back into the tank and it's working fine for now anyway. Hope this little gremlin doesn't rear it's ugly head again. If it does I guess a new pump assembly maybe in order. Thanks for all your help!

 
Rep Power: 517

Good to hear.
I bet this would be a good place to try a labscope with an amp clamp, get a pattern from the pump and watch the 8 individual sections as the pump motor turns. Probably a little too high-tech for a non pro though. Hell, it's too high-tech for most mechanics that I know.

Any loose terminals in there? Female terminals that didn't have a tight grip on the male terminals? Oh well, I guess it will be getting a pump later on.