OBC Chiming - what does it mean?

[songzunhuang]

So I have been having intermittent OBC (On Board Computer) problems ever since the alarm horn went on and wouldn't stop. I ended up disconnecting the alarm horn and everything appeared to be fine. My OBC acted as expected.

Then one day, the OBC screen went dark. While driving around I started noticing an intermittent chime. I've never heard it before. This went on for about 2 days. Then without any rhyme or reason, my OBC screen came back on again. It worked for about 4 days. I checked and utilized all the functions and it was fine. I never heard a chime.

Well, yesterday my OBC screen went dark again. And, you guessed it, the chime is back.

I've driven over 350 miles commuting since my constant alarm horn incident and the subsequent OBC weirdness. All instruments are fine and everything seems to be great - except for the OBC.

Anyone have any idea what the chiming means in my car? It's a 1984 633CSi. Thanks for any insight.

[baders]

Song. On my 1986 635 the chime operates as below;

When ignition key switch activated with drivers door open.
Seatbelt switch.
OBC speed limit settings.

There may be others too, that's all I can remember (old age).

[Stoffie]

For my 1984 M635CSi, the only times I've heard a chime are speed limit and outside temp dropping below 3°C.

[sansouci]

I only get the chime at low outside temp as an icy road warning.

[songzunhuang]

OK, I will have to test the "Door Open" case. I really can't test the below freezing temp case as in California where I live, it may be a long, long time before those kinds of temps arise.

The speed case is interesting. I do notice it chiming when I drive. However, I haven't set any speed (no display right now). Is there a default speed for a chime in a USA version?

Today I am going to pull the OBC main unit and check the fuse and see if I can spot any relays in it. Some have told me that they think I have a relay issue (for the blaring horn). We will see.

I'll continue to gather info and would much appreciate others "chiming" in. Forgive the pun.

[songzunhuang]

I pulled the main OBC computer and looked for something resembling a relay - nothing. The OBC computer is just two circuit boards facing each other with the components on the inside and the PC board circuits on the outside. Not much I could do, but I did check the fuse (ok) and also sprayed some electronics cleaner liberally everywhere. When I put it back together, it was the same.

So today as I was driving to a school event, the chiming reached new levels. I would get a chime every few minutes the entire duration of the trip. The OBC screen was still dark. I returned from the event and the same thing kept happening.

Later, I went to get gas for the car. After the fillup, the OBC screen came back on. I set the clock 3:51p and then checked all the functions. It all worked. During the trip home from the gas station, no chimes. Now tomorrow when I commute to work, we will see what's in store for us. Sheesh.

Maybe I'll just live with it and count it as a blessing when it all works.

[songzunhuang]

Here are a few more shots of the OBC main computer. I thought you may be interested in seeing it, although I am not sure how much help it'll be.

[baders]

Could that copper block way back there be a relay or sorts? That's the only thing that could slightly be a relay, but I don't know.

Yes, that could very well be a relay. Need better pictures.

[GripGreg]

I can see that the serial numbers match!

[Brucey]

on my car the chime is a separate module in the knee panel. If it drives you nuts, just unplug it!

BTW one reason for the chime is if the external temperature drops below a certain point (freezing) . Unfortunately the temp sensor is such that if its connection goes intermittent, or breaks it reads as an absurdly low temperature, and sets the chime off.

When I bought my car it had a failed ext temperature sensor and a failed chime. Probably not unrelated to one another....

cheers

[songzunhuang]

on my car the chime is a separate module in the knee panel. If it drives you nuts, just unplug it!

BTW one reason for the chime is if the external temperature drops below a certain point (freezing) . Unfortunately the temp sensor is such that if its connection goes intermittent, or breaks it reads as an absurdly low temperature, and sets the chime off.

When I bought my car it had a failed ext temperature sensor and a failed chime. Probably not unrelated to one another....

cheers

Brucey, it only drives me nuts when it does it repeatedly every few minutes. A weird new behavior started today. I now get a low tone beep. It's no longer the chime! In the last 24 hours, my screen has come on and off a few times. It would chime when the screen was off and now I am getting a low beep instead of a chime.

I don't think it's my temp sensor as each time that the screen is working, I've checked the temp and it's always been reasonably close. Also where I live in California, it rarely drops below freezing. Lows at night are closer to 45-55 degrees.

I'm thinking that I may try and replace the OBC main unit. I saw a used one on eBay. I'm not sure if a used one of the same vintage will be much better, but who knows.

Are there people on the forum who have spares that they would be willing to let someone swap out temporarily as a test? Are there any know companies that can test an existing OBC main unit?

At this point, I may move on to other things that I can actually affect. I'm running out of ideas with the OBC...

[GripGreg]

Like the suspension?

[songzunhuang]

Like the suspension?

Yes, like the suspension. I was pushing on each corner of the car and watching the rebound this evening. It seems pretty reasonable. There's no uncontrolled oscillation. I've always thought my front was too high. Instead of changing all the springs, maybe I'll just get a lowering front spring.

Oh, and today on the ride home, the OBC came on again. I set the clock and then I drove the 35 minutes to the house and checked temp, MPG, range, set the timer, used the stopwatch, etc. Everything worked! No chimes either.

I swear the OBC is possessed! I'm moving on.

[GripGreg]

While you have both front springs off, that's the time to change upper & lower control arms!
Maybe the center link, too? Then do the rear when you want to.
Then get a four wheel alignment and you'll fall in love!!
Have you checked for your Pitman Arms/dog bones? I remembered, huh?
Doing it at the same time saves you having to repeat things.
You'll notice a hugh difference in handling.
Does your steering wheel look like it should be turning the car because it's not
quite centered? It's because you need an alignment. It happened to me!
The four-wheel alignment straightened it right up!
Good luck,,,,Greg

[sansouci]

One failure point in the circuit boards beside the solder joints is/are the capacitors. Not sure how to check each one but there are high quality (and low) out there that audiophiles drool over.

[songzunhuang]

One failure point in the circuit boards beside the solder joints is/are the capacitors. Not sure how to check each one but there are high quality (and low) out there that audiophiles drool over.

OK, my OBC has been dead for a week now. I am wondering if there's anyone I could send my main unit to that will plug it into their car and check to see if the unit is good. I really don't know how else to troubleshoot this. I'd hate to buy other used (and maybe broken) units just to test this. Arg...

Car is running great. Just stupid sniggling things like this driving me nuts.

[GripGreg]

Enough with the OBC! Get your suspension right,,,,,please!?
On the list of twenty things to do, the OBC should be maybe,,, nineteen?
Sorry!

IMHO, you seem like someone doing 70mph or so on the I #80 or whatever and answering your cell phone just because it rings!
What's more important,, safety, or the extra lights?
Again, sorry but, I'm the victim of a rear-ender because of a stupid ass cell phone!!
Please forgive me,,we all have baggage!
I will continue to offer all I know to you,,,,Greg

[songzunhuang]

Enough with the OBC! Get your suspension right,,,,,please!?
On the list of twenty things to do, the OBC should be maybe,,, nineteen?
Sorry!

IMHO, you seem like someone doing 70mph or so on the I #80 or whatever and answering your cell phone just because it rings!
What's more important,, safety, or the extra lights?
Again, sorry but, I'm the victim of a rear-ender because of a stupid ass cell phone!!
Please forgive me,,we all have baggage!
I will continue to offer all I know to you,,,,Greg

LOL! I'm a computer guy. Malfunctioning computers really bother me. It's just the way I am put together.
I did install a modern stereo with nice bluetooth handsfree so that I can take and make calls without distraction from the road. It works quite well.

I have a feeling I'll just have to replace the entire stinking suspension. I'll have to save up for that one. I'm trying to meet up with some other e24 folks in Northern California and get a 2nd opinion on my suspension. Maybe it's not so bad and I am just totally warped because my other driver is an S2000 and that handles like a go-cart (in a good way).

Right now the excessive play in the steering wheel is bugging me. It just seems so "loose".

[GripGreg]

Again, forgive me! I forgot you're a computer geek. Glad to know about your bluetooth set-up too.
Also, in one of my early postings to you, I suggested what to replace in your suspension.
Knowing what you've replaced, that job won't be too difficult for you.
Just gather everything before you dive in. And get a four-wheel alignment right away?

Also, your car, although it's a GT, will never feel like a nimble go-kart IMHO!
And, your Honda will never have the plush feel of your 633!

Good luck and again, forgive me for my rant and my baggage?
Greg

[songzunhuang]

Greg, it's all taken in a positive spirit. No worries. I really appreciate how everyone is supportive on this forum. I know your intentions are good. With that in mind, I jacked up up the front of my car and messed around with the front suspension links today to see what was going on. Well, the culprit was freaking obvious. I know why my car feels like a boat.

The ball joint in my center link connected to the pitman arm (which is connected to the steering box), is super worn and loose. Check out this video I took of the play in the link.
https://youtu.be/7L3exkEVfys

I basically grabbed a wheel and oscillated it by hand while taking the video.

I've got a new link ordered and I'll get it in this weekend. Can't wait to get it in as I am sure the car will feel SO much better. Yeah, not much scares me on this car now. All the mechanical bits make perfect sense. It's that damn OBC! Not so easy to troubleshoot and fix.

[GripGreg]

I suggest that while you're under the car, that you check the upper & lower control arms for looseness or, if you see any separating of the rubber bushings, change them!! Now's the time! But, have everything in hand in advance.
Again, it'll eliminate you going back to the job. Same for the rear end, maybe the next week-end; then get that four-wheel alignment. Remember I mentioned this before?
What I said was ALL the rubber needs to be replaced.
Good luck,,,,Greg

[songzunhuang]

I suggest that while you're under the car, that you check the upper & lower control arms for looseness or, if you see any separating of the rubber bushings, change them!! Now's the time! But, have everything in hand in advance.
Again, it'll eliminate you going back to the job. Same for the rear end, maybe the next week-end; then get that four-wheel alignment. Remember I mentioned this before?
What I said was ALL the rubber needs to be replaced.
Good luck,,,,Greg

I have realized that the topic of this thread is completely shifted! I will no longer talk about my suspension in the OBC thread.

If you goto my project thread page 6, you'll see that I replaced my Center link with the loose balljoint today. viewtopic.php?f=25&t=25858&start=125

My car no longer feels like a boat. As for the rest of the links, they all felt tight with no play, but I do see a few worn rubber boots and grease seepage. I'll have to get to that one day....one day.

[songzunhuang]

GripGreg - I thought you would be "entertained" to learn that I just purchased a OBC Main unit on eBay. I can't seem to figure out how else to test the operation of mine, so I am going to swap it with another. Perhaps it'll work, perhaps not.

Oh, as a salve, I also got a ball joint separator and will slowly replace all joints with bad boots or seeping grease. I did spot a few suspect joints, but there was no play.

Today, I tackle diodes in my aftermarket keyless remote...that's a different story.

[songzunhuang]

Again, forgive me! I forgot you're a computer geek. Glad to know about your bluetooth set-up too.
Also, in one of my early postings to you, I suggested what to replace in your suspension.
Knowing what you've replaced, that job won't be too difficult for you.
Just gather everything before you dive in. And get a four-wheel alignment right away?

Also, your car, although it's a GT, will never feel like a nimble go-kart IMHO!
And, your Honda will never have the plush feel of your 633!

Good luck and again, forgive me for my rant and my baggage?
Greg

I received my replacement OBC today and installed it this morning. I think my OBC woes may be over! See this post for some details.
viewtopic.php?f=25&t=25858&p=189983#p189983

Now I can focus full attention on the rear suspension.
I'm thinking shocks and springs for the rear and new springs only for the front. I'm leaning towards the BavAuto lowering springs. I have to meter my purchases as I noticed while under the car that I will need new front tires soon. The money pit lives on...

[songzunhuang]

Again, forgive me! I forgot you're a computer geek. Glad to know about your bluetooth set-up too.
Also, in one of my early postings to you, I suggested what to replace in your suspension.
Knowing what you've replaced, that job won't be too difficult for you.
Just gather everything before you dive in. And get a four-wheel alignment right away?

Also, your car, although it's a GT, will never feel like a nimble go-kart IMHO!
And, your Honda will never have the plush feel of your 633!

Good luck and again, forgive me for my rant and my baggage?
Greg

I received my replacement OBC today and installed it this morning. I think my OBC woes may be over! See this post (bottom of page) for some details.
viewtopic.php?f=25&t=25858&p=189983#p189983

Now I can focus full attention on the rear suspension.
I'm thinking shocks and springs for the rear and new springs only for the front. I'm leaning towards the BavAuto lowering springs. I have to meter my purchases as I noticed while under the car that I will need new front tires soon. The money pit lives on...