Mid 80s-Early 90s Accord, Civic & Prelude: Main Relay Fix

[Kaspin]

This may apply to mid 80's - early 90's civics and accords as well. The pictures and instructions below are specific to 88-91 Preludes, but should other cars should be similar. The Symptoms: Car will crank, and maybe run for a second, then dies quickly, and won't restart on a hot sunny day or after running the heater full blast for a while, and will start fine after cooling for a couple minutes. The Cause: The solder points on the printed circuit board inside the main relay become cracked/loose over time and the heat causes them to expand just enough to break electrical contact. (the main relay provides power to the fuel pump) If you don't know how to solder or are unconfortable in repairing your own, you can probably take it an electronics store (not radio shack) and they can do it for you. Or just buy a whole new one. What you'll need: - Philips head screw driver - small flat head screw driver - 10mm socket - rachet with 6" extension - a soldering iron (I have a 30watt, but a 40w probably would've been better) - some solder - some time. If I had to do it again, I can get it out and back in, in about 30min. But you should probably give yourself about an hour to be safe. Before starting, be sure you're ready to solder or have a replacement relay ready to go (your car won't run once you remove it). Remove the coin tray covering the fuse panel. Remove the 5 philips screws holding the plastic cover under the steering column. (1 in each corner, 1 where the coin tray was) Unplug the 3 electrical connectors attached to the plastic cover, taking note where each one goes. Using the 10mm socket and the rachet with extension, remove the 2 bolts holding the fuse panel up. Work the panel out from under the dash. You'll have to disconnect some of the shorter wire connectors to get it all the way out. Unplug the connector from the main relay. Use the small flat head screw driver to press on the tab that locks the main relay onto the fuse panel and slide the relay off. Remove the plastic cover from the relay. You'll see the printed circiut board and all the solder points. Add a little solder to each making sure you melt the old solder. Put everything back the way it came out and start it up!

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[98CoupeV6]

Good stuff. Thanks for posting

[95AccordEXR]

SWEET... my 88 accord will be getting this treatment

[chorusoftribes]

I've poured about four hours into finding my main relay and i don't believe i'm missing it anywhere. there are quite a few good links out there on how to and why.

1. http://autorepair.about.com/cs/troub.../aa010301a.htm
2. http://techauto.tripod.com/mainrelaydefine.htm
3. http://mustardcat.brinkster.net/p3g/.../mainrelay.htm

But still can't find the bloody thing. I'm in a 1988 Accord LX. It's carburated, i just aquired it. Yesterday i narrowed it down to no fuel. (It started when I poured down the carb) So it's either fuel pump or no power to it. I've got the fusepanel out even just to get a good look around (3hrs worth) and still nothing. I'm not blind either.

Is there anywhere else it could be? Is it possible that it wouldn't have one?

Help!!!

Jason

[VPUPPY]

i think the main fuel relay applies to PGMFI cars or fuel injected honda. i don't think they are for carburated hondas, could be wrong though.

[JimBlake]

Got a repair manual for your '88 LX? The 'main relay' is a combination relay to power the fuel pump, ECU, & fuel injectors. Since you don't have injectors, Honda probably did something slightly different for the carbed cars. Like maybe a normal-looking relay instead of a long one. The PGM-FI 'Main' relay is really just 2 or 3 relays combined into the same case.

[91Lude]

A week ago I had the described problem, only it was about 40 degrees outside when my car wouldn't start. I checked the fuel pump/alternator fuse under the dash and it was a little lose so I plugged it in all the way and fired right up. Today I am having the same exact problem in the same cold weather after my car has run fine for a week. Do you think that I need to replace my relay? I was thinking maybe there is a relay fuse, but it's not in the fuse box in the engine or under the dash, is there another fuse box I don't know about?

Please help

Thanks,
JP

[Demonsport]

Thanks to the info in this thread.. I've now replaced the relay and my 'lude is back roaming the streets.. and to think, all it took was $75 and 20 min. Now I feel like an a$$ for letting the thing sit for so long, of course, with nearly 200k miles.. you tend to think the worst.

Now all I gotta do is get my money back from taxes and its ACCESSORY time!!

[Zain]

1990 Honda Accord Main relay

I have located the main relay left to the steering wheel. I have also disconnected the wire connector to the relay. Can any one guide me how do I take out the main relay ?
Thanks
Zain

[wedley2]

Originally Posted by Zain

1990 Honda Accord Main relay

I have located the main relay left to the steering wheel. I have also disconnected the wire connector to the relay. Can any one guide me how do I take out the main relay ?
Thanks
Zain

i think there are 2-3 10 mm bolts holding a silver box, you need to take these off and the box in order to acess the main relay. i need to do this soon on my accord as well.

[razirbel]

Thanks to this thread for help diagnosing the problem, and displaying how to fix the relay without blowing a wad on an overpriced new one. I'd like to add that the reason the old solder joints most likely failed is due to the thickness of the connector prongs that the printed circuit board needed to connect to. You need alot of heat in order to get those pins hot enough to accept solder wicking. We have a nice HAKO adjustable soldering iron here, i cranked it all the way up to 900 degrees Fahrenheit in order to get the prongs hot enough to accept solder. Just don't leave the iron on too long, or you could melt some plastic or cause a trace to come off the pcb (you'd have to really have it on a long time to damage something though). So, just make sure you hold the solder tip against the pins and the circuit board, and don't just melt the solder on the printed circuit board, or chances are, you'll have the same problem again. (It's fairly easy to notice when the solder doesn't adhere to the pins, in a previous photo on this thread, you could see where the solder kind of mounds up, and there's a slight crater with the prong in the middle. A good solder joint will not have the crater, because the pin will be hot enough for the solder to stick to it, should be nice and smooth).

[mikemerc85]

i had this problem when i first got my lude, that it would start but then die and sometimes didnt wanna start when it was cold, and it ended up bein the main relay.

[Carfan1]

Had this problem on an old civic I owned. Simple way to diag this is crank the car and smack the panel where the relay is...see if it starts. I did this for about two weeks, then one of the techs told me he had an extra...doh

[90crx]

If you're going to take the pgm-fi relay completely apart to repair the solder joints you can replace the two individual relays real easy. NTE part # R52-1D40-12. The specs on this relay is twice the ratings of the original and they only cost $3.00 or less apiece depending on where you get them. I have rebuilt two relays that were toast for less than $7 each and they work great.

[Joshatdot]

tag, my 91 Accord LX has the same problem

[3rdgear]

I wish I would have seen this like 2 weeks ago it would have saved me 50 bucks..

[tayabd]

i have aflat tire, cause me alot of damage like the whole front driver side of light was broke

[Colnago]

Thank you VERY much for this great thread. I have had this problem with my car for a few months already and couldn't figure out what the problem was. I didn't think I had the money to fix it, and it would start fine for the most part so I ignored it for a while, until yesterday. My car just would not start up for a full 24 hours and it finally turned on today. It never ran rough while it was running.

It was a $7 fix to just re-solder the relay and it's working great now.

btw....if anyone's curious as to why the car only has difficulty starting up but once it's running doesn't die, a good explanation can be found in the following:

http://www.tegger.com/hondafaq/mainr...y.html#michael

Everything made sense once I read it.

Thanks again to everyone for taking the time to put this stuff up.

[themonsteraria]

Nice. I'll use this on my buddies Accord, that is having exactly those symptoms.