91 SE Main Relay

In the summer months, there were several occassions when my car wouldn't start, and on this forum I learned that the problem might be due to heat building up inside the car causing the main relay to fail. My cheap solution was to open all the windows and let the car cool down. No problems occured in the fall. Now that winter is here, my car has stalled a few times while in motion (at slow speeds). Luckily it restarts quite quickly.

Might this be due to the same fault, because I have the heat cranked, thus warming the interior?

Gaffertape
Toronto Canada

I doubt it. If the main relay were at fault, I don't think it would restart so readily.

That's not to say that you mightn't have a main relay problem ALSO!
:(

One good thing is that the main relay fix is easy and should probably be done in any case. If it hasn't failed by now it probably will soon. You need to remove the relay and resolder all the pc board connection points and then reinstall. That will probably take care of your summer problem and might take care of the winter problem too.

mpumas - I've owned 3 (used) Hondas, and put 100,000 miles on each of 2 of them and 30,000 on the third. And the main relay has NEVER gone out.

I don't question that this might be Gaffertape's problem, but it ISN'T like changing the timing belt on a regular basis!

Accordcodger you may be just lucky. There are so few things that can be fixed on the HONDA so cheaply. And based on his statement that he has had problems during the hot weather, it isn't a bad idea to just do it.

I might be able to help you out. Here is how the sequence went with mine (91 SE also). This was before I owned it but have the paper work from Honda when it went in for a no-start problem.

8/13/03 (166,535 miles) - customer states the car was parked in lot for several hours in the heat & would not start.

1) replaced ignition switch $70.64 and found no spark.

2) Replaced coil $98.98 & checked several times sitting in the heat. Started OK.

8/19/03 (166,615 miles) - (She didn't get very far :lol2:) same problem as above

1) main relay ($65.66) replaced - been running fine ever since.

Might help, might not....figured it's worth a mention.

I had hoped the problem might simply be some ice in the gas line, but even after an evening in a warm garage with methyl hydrate added to the tank, the car behaves the same.

Could be fuel supply, could be power. If its power, it only affects the engine: Warning lights come on and the headlights remain active when it stalls. Yet if it were a fuel issue I'd expect some jerkiness, some sign that it was about to stall, but it runs like a top right up until it decides to quit.

The Honda mechanic told me that they might spend hours trying to find the problem, it would cost a bundle, and they still might not find the source of the problem.

Will I see anything unusual if I yank the Main Relay? In other words, if its faulty, will it LOOK faulty?

The main relay module really is two relays and a few diodes. If it fails, the problem is usually bad solder connections where the relays attach to the mounting board. The fix is cheap and easy once you get the assembly out. Just reheat all the connections with a soldering iron. You might see the problem if you look at the connections with a magnifying glass. In my troubleshooting guide, I recommend isolating the problem to an area, then doing the easy cheap things first then moving to more expensive difficult fixes.

New main relay purchased, but we haven't swapped it out yet. Hopefully it will make the difference. I'll report back when we find out if it was successful in curing the problem or not.

Replaced the sparkplug leads, the distributor cap and the main relay. Also hooked up a fuel pressure gauge to the manifold and a lead to plug # 1 to check for spark.

Car continued to stall. During the few minutes trying to restart immediately after the stall, fuel pressure was fine, but no spark. After a few minutes the spark re-appeared and it started. Thus an ignition problem and not a fuel problem.

Swapped out an item within the distributor (the ignitor I think it was called) and we had the car up and running for a good hour and a half without stalling. More road tests planned for tomorrow to confirm that the problem is truly fixed. If it fails again, the only items left are the ignition coil and the computer module.

Gaff

Looks like the ignitor (hope I have that name right) was the key. Its a ceramic unit with about 4 electrical connections attached to a heat sink within the distributor.

The car is up and running again.

Gaff

That is what they call it but I think they call it an igniter. You may have also solved your problem on starting problems during hot weather with the change to the main relay. I hope you saved the parts. The main relay is repairable.