PGM-FI Main Relay repair

[knarg]

My main relay has been failing to run the fuel pump, so I removed, inspected, and repaired the PCB on the main relay. Most of the joints were dry and did not have enough solder. I found some cracks and other abnormalities, so I de-soldered and re-soldered these connections. Here's what I've done, in picture summary,


https://images.oreillyauto.com/parts/img/large/sti/ry-156_front.jpg


Documented this because I know others have had this problem. This is a cheap, easy solution if you have the time and know-how.

[Nio]

Great guide.

I remember when mine failed, it was a pain to get to, and then I just bought a new one for like 50-60$.

:3 would have been nice to know this, should be good info for future use.

:thumbup:

[2ndGenGuy]

Nice work man! Glad to see you're still around workin' on that sweet, sweet hatchie!

[DBMaster]

When mine started acting up I just ordered a new one. I took the old apart and sprayed the innards with tuner (electronics) cleaner spray to keep it operating while I waited for the one I ordered. It did just as much for it as re-soldering. The device is part mechanical, too. Since the part's not that expensive I'd just as soon replace the thing. I think I paid $40.

[knarg]

I took it as an opportunity to practice soldering and save some money in the process. It's working great now.

[Dr_Snooz]

The relay in my relay was bad. I had to replace the whole unit.

[DBMaster]

I figure once it gets to be this old the relay, which is mechanical, has gone through so many cycles that I would rather pony up the $40 and be sure not to get stuck.

I personally think it's that handling and jostling of the innards that temporarily frees up the relay rather than the actual soldering being the fix. That's just my opinion and you know what they say about opinions.

[AccordEpicenter]

in ALL of the main relays that Ive taken apart that had issues, the solder joints where most def bad, like terrible bad. As long as you de solder the bad joints (using a solder sucker or desoldering braid) and re soldering them and making sure they are good joints, you should be good to go

[DBMaster]

You KNOW what they say about opinions.

If I have the car long enough for the relay to go bad again, I'll try the re-solder fix. Maybe Mitsuba resolved the issue since our cars were new and the new relay I bought almost a decade ago will last forever.

[AZmike]

in ALL of the main relays that Ive taken apart that had issues, the solder joints where most def bad, like terrible bad. As long as you de solder the bad joints (using a solder sucker or desoldering braid) and re soldering them and making sure they are good joints, you should be good to go

I resoldered the main relay in my hatch about 6 years ago. After a few years I started having very occasional trouble starting so I resoldered it again. A few weeks later I ended up stranded for about an hour until I got the fuel pump running. The main relay passed all tests so I replaced the fuel pump--same problem. My resoldered relay would pass all diagnostic tests, but the fuel pump still wouldn't run. A new relay solved the problem and my 410k fuel pump is still working fine.

The bottom line is if money's not too tight a new replacement is a better choice. Solder joints aren't the only thing that can go bad.

[AccordB20A]

yeah ive had a couple internally fail with the relays in side them

[A18A]

I've always kept a spare one in my glove box lol

[DBMaster]

^^That's an EXCELLENT idea. I may order one for myself. Since I did not put it back in the original screwed up location it's easy to change with no tools.

[knarg]

UPDATE: Main relay is working like a champ so far--repair success!

[JDMPrelude23]

great thread.. I just replaced mine.. i couldnt even get my old one out it was way too much work so i just have the new one there hanging lol

[Oldblueaccord]

Main Relay info (https://www.3geez.com/forum/efi-tech/45595-main-relay-info.html)

I'll add my write up to the bottom. The tech power up link might need permission to use it. The tech link is the 100% best way to troubleshoot the Main relay.

[charliekuney]

lol, I forward this thread to people on Craigslist with these cars that "crank but won't start."

[rodan32]

Darn it Charlie, now where am I going to get a cheap back-up Accord?

[pedrosa]

nice work friend! i had same problem with fuel pump, many thanks for your info

[pedrosa]

main relay repaired following your INFO,7646
many thanks !7647

[Oldblueaccord]

There seems to be some misinformation on the main relays function I wanted to try and clear up.

First off I have a 1988 Lx-i with about 260k ( this was in 2005). J code car.

I started the car with the relay hooked up. Runs.

I unhooked the relay and start the car again. Car cranks over will not start.

I hooked the relay up started the car. Runs.

EDIT: http://67.129.153.73/CGv2Production/...9400SE3003.jpg (picture from rock auto)

While it was running I unhooked the relay. Car stalls.

Understand that a bad main relay means you have no fuel, but the car will crank over but not run.

12-64 Helms service manual step 9. Connect a jumper wire between the Blk/Yel #5 and the Yel #7 the pump should work with the ignition switch on.

This is a good test to see if the relay is faulty or not. Also to get you home in a jam if you car wont start.

Remember the relay is there for safety purposes so that in the event your in an accident the pump does not keep running and cause or keep fueling a fire.