My 99 would die unexpectedly. Turned out to be the ign switch. Replaced by Honda for free. After a few years it started doing it again. Called Honda and they said they would replace for free but it had to die in front of them. Well, I did not want to drive the van any longer because it was not safe. So I bought a replacement switch from ebay aftermarket and it has been fine ever since.
My main relay has been fine. I've taken it out and inspected for solder cracks.

 

Odds ar


Odds are that it is the Main Relay. Do a search in this forum for Main Relay for more info.
Many times it is after the relay warms up that the failure happens due to expansion and contraction.
Buffalo4
PS: It is possible to be the ignition switch also, but the Main Relay is more often the reason.

 

And considering the main relay can be inspected for a grand total of $0, I would start there before considering an ignition switch.

 

Update:

Removed the main relay and this is what I found, see photo below. Is that damaged solder going to the pump relay behind it?

Guess soldering is going to be the answer for now and try and find one at a junk yard

 

use some flux and silver solder youll be good as new... the track isnt lifting from the board, just seems like poor quality solder that couldn't take the heat.

 

Bro that's always been my downside, soldering. I have a craftsman pistol solder gun and I guess basic solder and I can't get the solder on the relay to melt. I have soldering paste but when the solder I have melts it just turns into a ball and slides away not sticking to the existing solder. Do I need specific Flux? How can I tell if my solder is silver?

 

Here are the only soldering tools I own, let me know if I'm missing anything or if I'm just not using them right.

Below is also the only thing its managed to do to the existing solder on the relay lol

 

I just found one that looks similar to it. The one I removed from the 02 ody is RZ-0158 and the one I found was RZ-0159. Are they interchangeable? I looked up online but cant find any answers also looked it up on a parts website and when I put my year, make and model…they show a RZ-0159 so not sure if I can use it or if one is a superseded part number maybe?.

 

the gun will be overkill unless you're very good and fast.
you'll burn the board and lift the track.

make sure the tip on the iron is clean and tinned, a wet sponge works well when its at full temp... then flux the post on the board, heat it and hit it with solder.

you're not trying to make a mil spec solder joint, as long as it flows well to the pin/connection and board you're good.
even if the solder balls up that wont be a big deal.

anything will beat what it looked like before.

 

Ended up going to HB and buying a cheap $5 solder iron and a $4 tube of rosin solder and this time it melted it as it was suppose to created a nice layer of solder above the damaged area like all the other solder points. I guess it was the other solder iron/gun that would not solder due to the tips being burnt/not cleaned. I was about to buy a $60 solder gun but glad this worked. Will install tomorrow and report. I will also check the ignition solder points for damage.

Here's the finished product:

 

GM everyone, installed the main relay and everything appears to be working normal. I mean it would start up before never had a start up issue but one thing it did have was like a slight “studder” at idle that isnt there anymore. Also, when I revved it the other day to about 5k, the needle came back down and van shut off, turned it back on and when I revved it again at idle, the needle would dip to about 500 and back to 1k rpm giving a slight sensation that it would shut off. Now I rev it high and it comes back down to normal rpm with no dip.

Its raining here so I will also be inspecting the ign switch for possible terminal solder damage and fix accordingly if so. I just hope this is the fix as I dont want to get stranded with the fam.

 

GM everyone, installed the main relay and everything appears to be working normal. I mean it would start up before never had a start up issue but one thing it did have was like a slight “studder” at idle that isnt there anymore. Also, when I revved it the other day to about 5k, the needle came back down and van shut off, turned it back on and when I revved it again at idle, the needle would dip to about 500 and back to 1k rpm giving a slight sensation that it would shut off. Now I rev it high and it comes back down to normal rpm with no dip.

Its raining here so I will also be inspecting the ign switch for possible terminal solder damage and fix accordingly if so. I just hope this is the fix as I dont want to get stranded with the fam.

It sure sounds like the Main Relay was the problem. I wouldn't worry a lot about the ignition switch unless some symptoms show.
Great job fixing it and posting back!!
Buffalo4

 

Man, you did a good job. I use a flux paste called Nokorode that works wonders with any type of solder (rosin core or solid), and given you did that without flux paste and only cored solder ... my hat's off to you. Great result.

Very wise to get a low-wattage soldering pen (as noted by @2011.2017.odyssey )

OF

 

Its 1st timers luck i guess. Kinda makes me want to have more to solder haha…

 

don't forget to tin your soldering iron tip when storing the iron, a good blob of solder on the tip then let it cool before moving it.

your tips will last significantly longer without oxidizing.

 

Regarding the mismatch in junkyard parts, generally with Honda main relays on any model if the connector is the same it's compatible (bring photos with you for reference), and more likely when it's definitely from the same model (Odyssey) and series (99-04) and even more likely when it's the same year as yours. This may not be quite as true for other parts but for main relays I find these rules to be very reliable. I don't think I looked at the number on one, ever, lol.

Also still a decent idea to have a used/junkyard spare and pre-resolder every large connection on the board which is what I have done for my 95, just in case it acts funny I can just field swap to the known good spare even just for process of elimination, as these solder joints can and do fail again even after a fixup, and the degradation is not always as completely obvious as yours was, it can be almost microscopic therefore the just resolder them all tactic. This relay is also a great security device considering if you unplug it and take it with you nobody can even hotwire it if they didn't bring their own spare, or find your spare hidden wherever, and are that smart. Mine no longer rides on the mount it just hangs so I can swap or remove it in seconds with no tools and less crawling around on the floor. Then again I'm not sure if the 99-04 series always has transponder keys (my 95 does not, and didn't have the option either, so it's easy to hotwire).

 

Great info!!! I was also told that by a Honda mechanic that as long as the plug fits, it would work as well. Drove the van and so far all is good and hopes that the issue doesnt return. Now I know to always carry an extra Main Relay in the glove box for safety reasons lol. Thanks all for your support.

 

You can test your ignition switch by wiggling the key around in the ignition while it is running. If it dies while wiggling the key around (but not turning the key to shut it off), there is a back electrical connection in there. Glad resoldering the main relay did the trick!

 

Wiggled the key while on and doesn't shut off or anything like that. Wiggled it for over a minute

 

Took it out for a drive today and while driving on a curve I noticed the van stuttered, attempted to shut off and regained power while driving at about 30mph. It all was in about 1-2 seconds. The van then felt a bit shakey but nothing else happened. I am afraid the main relay solder wasnt the only issue and now concerned to take it on longer drives that it will stall again.

I am now thinking of changing out the fuel filter and possibly buying a new main relay instead of leaving this repaired one on.

Further ideas of things to look into welcome!

 

Did you get a number of lights illuminating on the dash when it just about died, or a "dead dash"?

OF

 

It was all very fast as I mentioned, a quick 1-2 secs. I dont recall any lights going on just the RPM needle dropping all the way down as when you shut your car off and quickly back up.

 

stick to your original strategy, swap the relay and observe.

 

This.

It's not common at all, but late Gen 2 Odysseys can develop a situation where the EGR valve lift is both commanded and interpreted incorrectly, causing a stumbling that almost shuts down the engine .... and then it revives itself after pumping the gas pedal while decelerating.

I had this happen several times with my 2003 EX, and it almost always happened in either 4th or 5th gear, at a very small part throttle deflection at 40 to 50 mph.

Still, I would still stick with the relay swap as mentioned before, and see what transpires.

OF

 

For me, the van would be running fine, I'd be at very light throttle in 4th or 5th gear, and it all-of-a-sudden felt like the rug got pulled out from under me. Kind of like the engine saying "Okay, let's stop nearly all fuel delivery right now."

Then, after what felt like coasting for a while, back to normal. No rhyme or reason.

OF

 

Hmm, well my symptoms was only that 1 time but perhaps it's just starting. My only thing that I haven't been able to fix is the slight vibration at idle and hiccup every few seconds, otherwise van runs great at all speeds and shifts great too

 

Replaced the RZ158 Main Relay with a OEM RZ159 and felt very good at startup. No apparent shake anymore. Let's hope it doesn't start again. I'm not sure I'll replace the EGR as most common symptoms of a bad/failing EGR don't match mine. Not to mention, no CEL in my car like almost all who experience a bad EGR