89civicdx

Friend came over with crx , had 2 main relays(soldered) both didn't work , was driving his car with jumped relay connector. He tried my working relay right out of my ef sedan...didn't work, no click. I tried one if his relays in my car ...same thing no click.

I then tried my relay which was working fine ..now it doesn't work, no click , engine light stays on. I then tried my relay in my EF hatchback...,clicks,works fine.

I then tried jumping my connector, pump turns on...car starts fine. Tried a couple more relays same thing....can't get it to click engine light stays on...no codes. Swapped ecu...same thing

What should I look for? Blown fuse?

CRXcaliber

Not sure, but maybe check this...



Doubt it though, since car starts when you jumper the connector. Although not sure what you are jumping in the connector, so may possible just be fuse 14 blown. After my main relay went out, I replaced it and still nothing... No fuel pump action, checked ECU- No power to it. Ended up being this fuse. Hope that helps you.

4drEF

Check thermostat ground.
Typical with the solid ECU light - maybe why your CEL is lit.

CRXcaliber

Makes sense. All part of the same circuit. I see there is also a connector in there. Could be bad as well. I'd check it all.

89civicdx

thanks guys This car is stock 1990 DX sedan. Let me go check this ground on thermostat . If it was the ground wouldn't that mean pin 2 in diagram below wouldn't be grounded when I test with the multimeter?

This is what I am jumping, there is one power lead and it is jumped to the pump. The pump doesn't turn off when you shut down the car so you have to un-jump it

The car drives fine like this , no CEL jumped , pull out the jumper and you get cel. I see there is a code 15 on the ecu...but the car drives fine...just came back from 1hr drive.

Honda'sAreDank

I'm having a similar issue. No CEL here. Yesterday I couldn't hear the fuel pump turn on. It was 95 degrees out, so I pulled the main relay out and some of the solder points looked bad so I re soldered them. I still couldn't hear the pump come on. I jumped the BLK/Yel and Yel/BLK with a paper clip to test the voltage and it checked out and it was getting proper voltage to the pump. The pump came on when it was jumped and I felt the click in the relay so I assumed I was good. I pulled the jumper out and tried starting it a few times and the fuel pump came on again and it worked for the rest of the night. I went out to start my car this morning, and it wont turn over again. Same thing that was happening before. I bought a new relay anyways and nothing. This morning after it wouldn't start, I jumped the pins got it started and pulled the jumper out. Now it's fine again. If I let it sit for a while (overnight) I have to jump the pins again and I'm good for the day. I'm sanding down the spot where the ground connects to the thermostat lightly to see if that helps with the contact. Let me know if you find out what your issue was and I'll do the same.

89civicdx

Hey all thanks

I checked Fuse 14 and it was blown. I think what happened is when I tried this guys relay that he had soldered he must have soldered it wrong. then when I tried his it blew my fuse. I replaced the fuse and it clicks and starts.



thanks

CRXcaliber

Sweet! Glad to help...

Btw, I'm not sure, but that fuse may blow in certain instances when the main relay goes out. I never tried a resoldered relay, didn't have my soldering tools available to fix mine (although I would have not soldered it wrong anyway). Just went and bought a new relay. Still got the old (bad) one and plan on fixing it for a spare to keep with me in the car for emergencies. I didn't bolt mine back to the car, just left it loose and stuck it back up under the dash. Figured maybe the vibrations wouldn't be as bad and mess up the new one as fast. They usually go bad because of vibration and the heavy coil on the board will ruin the solder joints over time.

Honda'sAreDank

Went out to start my car today and the pump won't turn on again. Jumped pins 5 and 7 and it comes on. Still having my issue here.

Ayrexxx

Solid! Good work HT

CRXcaliber

My guess is that the contacts I have circled in blue in the main relay are bad/dirty or not closing at all. Or the primary coil windings are open between pins 4 and 8. Doubtful that's happened though since your ECU is working. There is no way to measure the coil with an ohmmeter since you have a kickback diode in the circuit to prevent voltage spikes from going backwards when the power is removed and the magnetic field in the coil collapses, inducing a current into the circuit. You may be able to clean the contacts by using some 800 grit sandpaper or an eraser, but I doubt it. Probably a sealed unit. Never really looked at the actual board. Just because it is clicking doesn't mean that the contacts are closing. Especially if they are burnt or dirty... As for the rest of the circuit, everything must be fine because it works when you jump it. You are, in fact, just eliminating the contacts when you do this. Hope that helps.



The only other thing there is the pin 8 circuit which goes to the ECU A12 and 14. It is labeled FLR 1 and FLR 2 on the ECU pinout. My guess is that it supplies ground for the relay when whatever conditions are met. You could try another ECU if you have one lying around, but I'm guessing that if it's not putting a ground there something else is causing that. What, I don't know... Probably nothing wrong there though since it also provides a ground for the ECU circuit at pin 3 when the other contacts close and the ECU seems to be working, which also tells me that the coil primary has to be good.

Honda'sAreDank

Yeah that's the crazy thing I bought a new main relay and it does the EXACT same thing. Yesterday I cleaned all my grounds (ECU thermostat ground, battery ground, and radiator support ground) with sandpaper. Since I had started the car running earlier via the paper clip jump (yellow/blk blk/yellow) it was good for the day so I couldn't tell until this morning of that was it. Of course this morning it does the same thing. It's just amazing because once I jump it to turn the fuel pump on it runs great all day. Can a bad battery cause the fuel pump to not come on unless it's jumped like that?

CRXcaliber

I doubt it. The battery cranks the car and that takes about 300 amps, so if it was bad you wouldn't get that far. Give me a min. There are some grounds in the back you may wanna check. I'll get you some diagrams up ASAP...

CRXcaliber

I don't know if you have a CRX or not, but this is the fuel pump ground. Check it and the connector in the harness. Even if you don't have a CRX it's probably similar and you can most likely find what you need. I'm gonna say the ground is good because you don't have any problems with the other stuff connected to it. Go for the connector and possibly the pump connections also first.





May be the pump going bad as well.

Honda'sAreDank

That's just the diagram I was looking for! Thank you. Yes I have a CRX. I will check that end of the wiring tomorrow. I checked the voltage at the pump connector and it was around 12v.

Honda'sAreDank

I went over the main relay ground and the rear ground that you showed me in the diagram. I sanded the contacts down and re installed. Still does the same thing. With out the pins jumped I checked the voltage at the pump and it was 12.13V via the multimeter. I wonder if the sock is plugged or something maybe the pump is just on its last leg.

CRXcaliber

Kinda wondering that myself. Doubt it's the sock, wouldn't work when jumped I would think. It is looking like a loose connection or maybe a pinched wire grounding out or something. I would check the pump first. There are connections on it where the harness attaches. As for the pinched wire, could be anywhere. Probably the pump though. Since there is no rhyme or reason to the problem (hitting a bump causing it to not work, etc...). You could take the pump out and see what happens when you check the voltage at the physical connection on the pump while it's not working. If you have it there and it's still not running it's going bad unless it isn't grounded. Just don't run it for more than a second or two since the pump uses fuel to lubricate it or you will burn it up for sure then. I would also check to see if you have ground to the chassis from the pump (while it's acting up) as well. Just make sure that it is showing its a** when you do the checks obviously, since you won't get anything useful if it's not messing up. You are running out of options here, so the pump is a good bet...