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!

 

Good stuff. Thanks for posting :thumbup:

 

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

 

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

 

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.

 

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.

 

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

 

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!!

 

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.