A Giblet of Friendly Advice
 

If something is starting to malfunction that can be damaged by heat, don't put off it's repair/replacement.

My damn main relay wen't completely today while I was on the way to my best friend's house. Ended up down a hill quite away from the house in 100 degree weather pushing the car with all my might. A cop even passed me but didn't offer help.

After stumbling inside out of breath and drenched with sweat I have vowed not to put off things that'll get broken in intense heat.

:(!

Yes, I replaced mine as soon as the GS community diagnosed the problem. I have the old one still. I garuntee it will work intermittantly until it fails completely. I will send it to you free of charge.

What does this part do exactly???

Because all of us own hondas so it might be of interest to me.

OBD-0 Main Relay strikes again!!!

Compaq - the main relay supplies power to vital components in the car - most importantly the fuel pump. When you turn your ignition to the 'ON' position, the main relay gets power from the ignition switch and in turn gives power to the fuel pump.

OBD-0 cars (88-91 civics and 4th gen accords) are plagued with main relays with poor solder connections - it's actually a result of a poor manufacturing process. Over the years of heating and cooling (expanding and contracting) of the soldered joints, the solder cracks. I took apart my old main relay and saw this for myself. Once the solder cracks, the trouble begins. On cool days, everything is fine because the joints are making a decent connection. On hot days, the heat causes the joints to expand giving an intermittent connection. This causes 'no-start' or 'shut-off' conditions, mainly when the fuel pump loses power due to the main relay.

If you are experiencing this problem, you should replace the main relay immediately, but in the mean time, I recommend rolling down all your windows and giving your car about 10 minutes, then trying to crank it. Usually this will allow the main relay to cool down enough to start.

For reference, the main relay is under the dash bolted to the inside driver's side of the car...right near the hood release handle.

Another option for someone who is good with a soldering iron is to re-solder an intermittently working relay. It takes some skill but works pretty well. I've been through this with old Volvo relays...exact same problem with thermal effects and cracking. In their case it was necessary to re-solder the contact points as well as trace the electrical paths on the PCB...I wasn't always successful.

I consider myself pretty good with a soldering iron. I tried this and still messed it up. It is an option, but a new one is only about $40. I actually ended up frying some AC components (how I don't know) by doing this. It is an option, just understand the risk.

whats a damn giblet...???
lol

A giblet must be something you are too young to understand!

Dax - thank you for the wonderful analysis of it. I'm just going to resolder mine. Would Dan's spare work for me or are the plugs/operation different for obd1 stuff?

Good luck with the solder. I think where I screwed up is that some of the solder dripped under the PCB and into the coil or something. If you do solder, I would say use as little solder as possible and do it inverted (this is how the board is soldered in the factory).

I'm not sure if OBD-1 main relays will work with OBD-0. Have you checked HondaAutomotiveParts.com to compare part numbers?

I'll do mine before I bug dan on his. I was gonna do it last night but by the time I got home I was too damn tired to care.