shintorojin

Hey all,
I have checked the post on testing the main relay.
What I need clarity on is how do I wire my battery and ground to it for testing while out of harness or if I am misunderstanding the process.

Any help would be greatly appreciated.
Car is a 1995 honda ballade(civic) 160i(sr4).
If I could get instructions to do a bench test without the car that would be great. But if not possible it's okay.

Why I am asking is that I tested and found that my relay was faulty, it smelt burnt so I got a new one which also appears to be faulty.

As a side note, if so. We one could tell me what varies I should get out of the power supply points from the harness that would be great to...

Thanks in advance,
Regards

Former User

The main relay has two separate power sources - directly from the battery and from the ignition switch. Have you tested voltage at both pins of the main relay connector?

shintorojin

Hi, I tested all 3 as recommended by previous post, the 3rd being the ecu power when key is cranked to start engine. I receive 11.5 on the first 2 and about 10.5 from the ecu port as I understand it. This was done while battery was running low. But I charged it and tried the relay again no response. Jumping terminal 1 and 7 and 5 and 7 causes the pump to prime.

Thanks for quick response

Former User

Check whether the ground wire attached to the thermostat housing is clean and tight.

When the key is turned to ON(II), does the CEL turn on and stay on or does it turn off after 2 seconds?

shintorojin

Hey, I decided to clean that ground before putting in the new relay actually, though it looked alright one difference I did notice after cleaning it was that with the battery drained from being unable to drive, where prior to cleaning it my starter would either crank or not, afterwards I got the clicking from the starter as is described when low battery.
So I left the car charging off my dad's car with jump leads for a while to make sure there was decent juice in the battery and the starter did it's crank thing as its been doing since the fuel pump hasn't worked.

As for the cel, from the get go it has stayed lit as long as the fuel pump doesn't prime. Initially when this first started, usually after driving a bit the cel would stay on and the pump wouldn't prime then after waiting/cycling the key on and off the pump would prime and the light would go off, second click(?) As I understand the order of the start system and the car would start.
I did notice increase battery drain but I initially thought the starter might be shorting out and causing the trouble.

But then obviously it just wouldn't get that far which is what prompted me to research and end up pulling the old relay and get a new one.
As far as I can tell I do hear what sounds like the first click but cel stays on and no other clicks.
I have checked the under dash and hood fuses, pulled and reseated them, all appeared still good.
Also cleaned the battery terminals and the negative terminal wire ground point, as well as the fuel pump connector and contacts just in case there was maybe some extra resistance the relay couldn't overcome.

Sorry if I'm coming across a bit confusingly, I am actually just a tech with a passion for fiddling with electronics and such, no real car repair experience aside from a few things I have fixed on this one over the years.

Former User

How do you know there's a parasitic drain? Or is this speculation?

shintorojin

Mostly speculation I guess, just seems like I've had to charge the battery more often of late. Though it could just be due to reticence to drive the car lol

Just as a side, most of the diagrams haven't matched my relay exactly so I thought I'd post a pic so you know what I mean when I talk about Jumping the 2 terminals




Original relay

Thanks again

Former User

Test the alternator.

Post pictures of the main relay connector showing the wire colors that match with the relay terminal numbers in your picture.

shintorojin

Had the alternator tested about a couple months back but will do so again though the battery is really the least of my worries at the moment. I did try getting the car going while jumped if that helps.
Sorry about the quality, not much light where the car is parked atm





Black blue and last one green/yel are on the clip side




Going to hit the sack for a few hours, will follow up in the daytime.
Thanks again for the prompt assistance!
Have a good evening!

Former User

Do the wire colors match with the second diagram I posted?

shintorojin

Last post then off. Thanks
Yes they appear to match, only saw the white line on the blue wire with the picture.
must stick a light under that dash.
Thanks again

shintorojin

Hey,
Yes the wire colors definitely match, just the numbering on my relay that doesn't.

As far as that testing procedure you posted, am I supposed to pull the battery and ground from the harness and use those to power the relay?
Would there be a way of doing it out of the car? (can I just use any 12v battery?)

Regards,

Edit 1: just to follow up, I realized I didn't actually test the ground on the harness yesterday so I went and did that quickly, everything still tests fine(11.5v on battery and ING power supply points and 10.2v on ecu power)

Looking between that harness diagram and the relay electrical schematic, they don't match up as far as I can see.

from my previous picture of the relay the pairs tested were 1&7, 5&7 and 6&7 on the harness side obviously. Still. Not sure how to power the relay without pulling the connectors from the harness which I am sort of reluctant to do.

Thanks again for the assistance, going back to the shop to get the new relay swopped if I can, seeing as I can energize the fuel pump with the testing procedure..

Former User

The pictures seem to indicate an exact match.

Yes

Open the main relay and inspect the solder joints. If cracked, you can resolder them.

Main Relay Fix, Troubleshooting (Honda, Acura) and how to solder

If the main relay tests fine, then the next step is to test voltage and ground at specific ECU connector pins. If these too are fine, then the ECU is bad.

shintorojin

I went back to the guy I got the "new" one from and he stopped it out with a used original one he says works. He can't test them so yeah.. .. Lol

If it is a problem with one of the ecu connectors do I have to be concerned with blowing the relay when I plug it in?
I'm thinking I should test the ecu connectors first either way. Wouldn't I have gotten no voltage on crank if the was a problem there though?

Can you give me link to the testing procedure for the ecu connectors?

Thanks for baring with me

Update1: I decided to pull the ecu while I was waiting and opened it up, everything appears to look good inside, no burnt smell no burn marks that I can see and no apparent dmg to any of the solder points.
I can post a pic if you'd like.

So I am hoping that it is safe to plug the new(old) one but I will wait to hear from you concerning testing the wiring and such.

Not sure if it means anything, but I tried Jumping the service connector before pulling the ecu and both without and without the old(my original) main relay plugged in I get a solid cel light, so not sure exactly what that means.

Former User

What ECU? OBD1?

There's a way to test whether the main relay works by grounding a wire in one of the ECU connectors.





CEL code 0

shintorojin

Yeah I got that it was code 0 but with ecu not looking damaged I wasn't sure if it actually meant a bad ecuecu or if it was to do with the missing or faulty main relay...

Could you explain to me how to do the test with some detail or if you have a link to a guide?

Also for testing the grounds for the ecu please?

Um I'd like to say obd1 since it's a 95 car, but how do I tell?
Update1: Just checked it out, it says p27 on the side so def obd1

Former User

Code 0 means the ECU doesn't have power or ground, or the ECU is bad. A bad main relay generally prevents the ECU from receiving power or ground.

See diagram I posted.

Plug the main relay back in.

Unplug ECU connector A. Turn key to the ON(II) position.

In unplugged ECU connector A, ground ECU pin A7 or A8 (Grn/Yel wire). Sometimes A8 doesn't have a wire, so grounding just A7 is sufficient. Does the fuel pump run as long as A7 is grounded?

shintorojin

Yes the pump runs when terminals a7 or a8 are grounded

Former User

Your main relay is fine. The problem is power or ground to the ECU or a bad ECU.

Now unplug both ECU connectors A and B.

With the key in ON(II), ECU connector pins A25 and B1 should read approximately battery voltage to body ground.

With the key off, ECU connector pins A26 and B2 should have continuity to body ground.

If all these tests are fine, then replace the ECU.

shintorojin

Hey just a quick clarification 1 starts from the beginning of connector A on the clip side or the back?

Former User

http://www.phearable.net/images/tech...schematics.gif

Maybe this will help:

A25 = Yel/Blk
B1 = Yel/Blk

A26 = Blk/Red
B2 = Brn/Blk

shintorojin

Thank you yes that helped perfectly and thanks for the diagram

On the other hand
A25 and B1 get 11.3volts - so close
A26 and B2 both have continuity.
So i guess that is that right?

Former User

Buy a known good ECU and enjoy a running car again.

shintorojin

Yep okay thank you so much again for all the help!

Guess this will be my xmas present to myself, at least I will be back on the road.

Will try to pick one up tomorrow, the guy said it would be about $140(R1700)

Any way i can get a new ecu, even aftermarket for this car?
Any use in trying to locate the problem in this ecu?

Former User

Probably, but it will be very expensive.

I don't this so. Used is the usual way to go.

Most people just buy a used ECU.