fuel pump relay location?

The black and yellow wire from the PGM-FI main relay going to the fuel pump is open.Dunno if you direct both power and ground from the battery -also check ground circuit see below if all okay here-think! computer

Check fuse no.2 and 4 in underdash fuse/relay box-

where is the fuel pump relay

The PGM-FI main relay powers the fuel pump relay. Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

93 Prelude Vtec sat for 5 months in hot Vegas weather & won't start now. I checked distributor & it meets all voltage to spec + I get spark at all plugs. Pulled fuel pump & connected it to 12volts it was locked up. Bought & tested new fuel pump with 12 volts and it runs fine. Installed new fuel pump and it won't turn on. Jumped black/yellow wires at fuel main relay & tested for continuity = new pump passed continuity test. Removed fuel shut off main relay, re-soldered all board connections & reinstalled. Visually inspected all fuses. The fuel pump still won't start.

Any thoughts?

Thanks,

Justin

Hi Justin,

Did fuel pump run when power was applied to Yellow/Green wire?

The fuel pump was not grounding properly. I properly ground the fuel pump and it works as it should.


Thanks all the same.


Justin

Hi Justin,

That was what I suspected ;)

Cheers. :)

my question is simple, how difficult would it be for me to aquire/change the fuel pump relay on my 1992 honda prelude? the reason i ask is because i took her to a mechanic i've used in the past and he quoted me right at $200 and i think he might be full of $#!^. I've attached a picture of what i think the fuel pump relay looks and its only $50 online. Basically, what i need to know is do i have the right part in mind and can i replace it myself? thank you

The PGM-FI main relay also powers the fuel pump located behind left side of dash above clutch pedal bracket.

i have spark but no fuel. i didn't hear the fuel pump kick on when i turn the key, so i pulled the access panel inthe trunk floor to check for power to the pump. my understanding was that if i had power to the pump, when i turned it over, then one of those wires should light my test light for a few seconds and then go out. but i tested all 5 wires and 2 green wires had power anytime the key was on but didn't shut off after a few seconds. the other three were white and did not light the tester. my first question is there a relay switch or a fusable link somewhere that i can check, and if so where the heck is it. i lost the manual!! also when this happened it happened all at once. i had just got done putting an oil pan on it and when i was done i started the car to see if it was leaking and then shut it off then i tryed to start it to pull it out of the garage and it wouldn't start so when i saw the gas gauge said empty i thought that was why it wouldn't start so i went and got gas and it still wouldn't start do you think there is any connection. or is it something electrical any help is greatly appreciated and i'm sorry i have nothing to donate but this car is nickle and diming me to death thanx jason

Hi jason carson,

The relay is located underdash above driver left leg. See pix by merlin2021.

Take it out and resolder the circuit board, it would save you time, money and many headaches later on.

.

KHlow2008 We do survive by donations, so don't encourage otherwise, please!

We help as much as we can with what you can give if nothing we will try to help. But the money does keep things going, kind of a catch 22.

I have a 1986 Honda Prelude 1.8L Carbureted Manual Trans. I'm only getting 2.7 volts to the fuel pump through the wire harness with the cut off relay in. When I try to by-pass the relay to test the fuel pump I get 0 volts with the ignition switch in the on
position. What could it be??

Power the fuel pump direct from the battery and see if it'll come on.If it does best test the main relay thoroughly-could be the injectors shorted out dragging down the voltage they tied in together to include all the solenoids-

The fuel pump powers on with 12 volts applied directly to it. This is a carbureted engine 2 carb 1.8L. No main relay just a fuel cut-off relay that tested good. What else do you think it could be?? The ignition module is new and I have a good spark also, pump is just not turning on when it's plugged into the harness. Can't even hear it turn on...really low voltage like 2.7 all the grounds are good. I have 12 volts at the fuse block. The pump doesn't have a fuse just the relay between it and the fuse block.

Sounds like a problem with the ignition switch-check the ignition coil if you have battery voltage on the pos. term. See diagram

Thanks I'll do that. Also when I measured the coil primary it was 1.9 ohms. The values should be 1.07 to 1.6 ohms so it's out of range slightly. The secondary is 9,300 ohms, the range should be 7,000 to 11,000 ohms. Could a bad ignition coil primary cause the pump not to turn on too by dragging the voltage down? I'm trying to understand this from an electronic perspective.

I checked the voltage on the + side of the ignition coil and it's 12 volts (battery voltage). Do you have a wiring diagram of the ignition coil, where ALL the wires go. There is a blue wire, a black/yellow wire and a black wire from the distributor harness. Could this possibly be the problem, the wiring of the coil? Right now the blue wire is on the - negative terminal, the black/yellow is on the + terminal, There is a brown wire from the switch harness going to the - terminal on the coil also.There is a larger black /yellow wire going to the switch harness that is on the - terminal. A gray ground to the body from the switch harness and two blue wires that go to a harness on the - terminal. The black wire from distributor harness is a bullet connector that plugs into a black/red wire on the harness. I'm going to check all the grounds and see if I have continuity.

Bad fuel pump relay! thanks for the help!!

Electrical problem
1985 Honda Prelude Front Wheel Drive Manual 120000 miles

I have a car which otherwise runs okay but cuts out after a while. I another Honda which wouldn't start if it was hot inside the car. I eventually heard about this safety cut off relay and replaced it. That was the end of the problem. But in the mean time we ended up replacing the fuel pump which didn't help by the way. I just need to know where it is on the 85 prelude. By the way when I went fro the replacement part the honda parts person said they were replacing 30 of these a year in a relatively small dealership.

For a 1985 Prelude The fuel cut off relay is located in the fuse and relay block under left side of dash