Little beeping box. What is it?

[herhuskyZ]

Hello there everybody. I bought a 280z about 2 years back that has clearly been heavily modified. Unfortunately that means often when I try to fix things, the original service manuals aren't much use because the previous owner added whatever he thought would be cool.

 

Recently something started beeping constantly and I found this little plastic box with a PCB in it underneath the center console. The 3 lights on the side are flashing and it is emitting a beeping noise. I know this box is not original, but I am not entirely sure what it does. My best guess is some sort of ECU tuning device. I swapped out the little 3V battery, hoping the noise would go away, but it did not. I just wanted to post here to see if anyone else has any clue as to the purpose of this little box and possibly has any idea about a solution for the beeping.

 

Thank you so much!

 

 

[Josh280z]

Not sure what the box is, but your best bet would be to start tracing the wires and see where they are going. Only then will you find out its true purpose.

[AZGhost623]

Hello there everybody. I bought a 280z about 2 years back that has clearly been heavily modified. Unfortunately that means often when I try to fix things, the original service manuals aren't much use because the previous owner added whatever he thought would be cool.

 

Still have the previous owners contact info? Thats where I would start...

[logr]

Warp drive engagement transluctor.

[LanceVance]

Warp drive engagement transluctor.

Hope he has a nice set of hydrospanners...

[herhuskyZ]

Hope he has a nice set of hydrospanners...

I'm always jealous of people in movies who are able to fix their warp drives in less than a minute while under blaster fire. It always takes me at least a day to fix mine.

 

 

But in all seriousness, I tried looking to see if I still had the previous owners contact information and had no success. I was hoping someone might recognize it or have seen something similar so that I could attempt to track down documentation for the thing since it has next to no information included on the PCB.

 

If I were to go tracing wires, does anyone know of any guides that could point me in the correct direction so that I am not going in totally blind? Thanks for the help.

[herhuskyZ]

Ok I found this image online of the Megasquirt v3. It has the same 3 LEDs along the side which seems to lend credence to my theory about the mysterious box acting as some sort of fuel injection brain. Is this some sort of home brew DIY contraption?

 

Edited July 21, 2014 by herhuskyZ

[NewZed]

Not sure what the box is, but your best bet would be to start tracing the wires and see where they are going. Only then will you find out its true purpose.

Here's a start.  Also, don't forget to look at the other side of the box.

Edited July 21, 2014 by NewZed

[AkRev]

Well, it is not Megasquirt. My best guess is the transistor went out, and your previous owner made a DIY CDI Trigger. The whole point of it is to read the trigger on the distributor and fire the coil. (should be the two wires on the bottom of your picture that go to the distributor.) 

 

Did you push the reset button?

 

Good Luck

[AkRev]

And I meant TCI not CDI, my bad. 

[herhuskyZ]

Well, it is not Megasquirt. My best guess is the transistor went out, and your previous owner made a DIY CDI Trigger. The whole point of it is to read the trigger on the distributor and fire the coil. (should be the two wires on the bottom of your picture that go to the distributor.) 

 

Did you push the reset button?

 

Good Luck

 

Sorry it took me so long to get back to you. Hopefully you're still around. And yes, I tried the reset button, but the beeping persisted :/

 

Thank you for giving me a direction to start poking around. I did a bit of research on CDI/TCI triggers and it unfortunately has left me more confused than I was before. If the box is controlling when the distributor sparks the plugs, how is the engine still able to run when the box is completely removed from the circuit? Does it just revert to some default mode?

[Six_Shooter]

Have you followed the wires yet?

[AkRev]

Trying to follow your question; are you saying you removed the box and the car ran? If so I am impressed and confused.

But in all seriousness this is the part that that box replaced. As I said before, I believe your previous owner had the part go bad, and went the DIY route.

You could do a few things, you could pull the tape off of the processor and try and search more about the board to trouble shoot. Also you can pick up a transistor unit from a member here (if you are desperate I can find one and send it to you, it would take a wile to find it in my storage but I am sure I have three) and rerun the wiring to the box. Helpful wiring diagram here. http://www.4moores.com/280z/files/test_76_280z_wiring%20copy.jpg

Things to keep in mind, PO might have done this due to a different coil with a dwell time unlike the stock coil. 

 

So, to be more helpful, let me give a few tips.

Pull the tape off of the processor and post a pic of the stamp underneath and I will see what I can dig up to help you troubleshoot. The buzzer is a warning, this warning could be do to two things, electronic failure on the board or coil that is on its way out. (notice any symptoms when driving)

Show us what you got, Take a picture of the coil, and the under side of the mystery box. This will allow me to see what it is that the previous owner did and changed. 

[AkRev]

And I just looked backed and missed answering your question. Instead I answered the question I wished you asked. (just kidding)

Basics of your distributor, you have electronic ignition. Inside the distributor, you will have a vr circuit with a 6 tooth trigger. This vr sensor creates a grounding signal each time a tooth passes by. The "Little beeping box" translates this low current grounding signal into a high current ground that fires the coil. Your coil will have a constant 12v power supply, as the "little beeping box" grounds the coil it will fire the coil for a set dwell time. During that dwell time, the coil will send a high voltage power to the rotor, the rotor must pass a plug in the cap to send this high voltage power during the dwell time of the coil. If this happens the only place the high voltage power can go is to jump across the spark plug and ground out. Without that little beeping box, non of this should happen, and your car will not run. 

 

Hope this helps. 

Good Luck

Edited July 27, 2014 by AkRev

[Tony D]

I don't think it's ignition related at all, more likely some sort of Alarm interface.

There would be no use putting multiple lights on a Reluctor Amplifier, and also a buzzer to beep, nor a battery.

 

I'm curious where the wires go to...since it was removed and it all "still works" telling us where the wires were connected would give us an idea on what it actually was doing.

 

It's a programmable EEPROM on there, so it may have had higher function ECU tweaking, but again, finding it in the center console instead of nearer to the ECU kind of throws that out---as well as only having two wires on it... An O2 sensor tweaker would have no need for a beeper or internal battery source.

 

Because a device simply has three LED's on it doesn't confer any similarity other than there are three LED's. Note the MS are all red. They indicate status of different circuits. Yours are Red Yellow and Green, indicating a 'good warning caution' sort of progression. Something checking one variable. 

 

Any Crank Trigger or CDI I ever dealt with rarely had one warning of failure light, if that. Input devices give a go-nogo again only needing one LED.

 

My curiousness surrounds what it was connected to in the vehicle. Anything else is wild supposition, and likely incorrect.

[Six_Shooter]

I don't think it's ignition related at all, more likely some sort of Alarm interface.

There would be no use putting multiple lights on a Reluctor Amplifier, and also a buzzer to beep, nor a battery.

 

I'm curious where the wires go to...since it was removed and it all "still works" telling us where the wires were connected would give us an idea on what it actually was doing.

 

It's a programmable EEPROM on there, so it may have had higher function ECU tweaking, but again, finding it in the center console instead of nearer to the ECU kind of throws that out---as well as only having two wires on it... An O2 sensor tweaker would have no need for a beeper or internal battery source.

 

Because a device simply has three LED's on it doesn't confer any similarity other than there are three LED's. Note the MS are all red. They indicate status of different circuits. Yours are Red Yellow and Green, indicating a 'good warning caution' sort of progression. Something checking one variable. 

 

Any Crank Trigger or CDI I ever dealt with rarely had one warning of failure light, if that. Input devices give a go-nogo again only needing one LED.

 

My curiousness surrounds what it was connected to in the vehicle. Anything else is wild supposition, and likely incorrect.

 

 

For once we agree on something.

 

Without finding what the other end of the wires are connected to, there's absolutely no way to know what it is, and even then, it can be speculation.

[Josh280z]

I'm so glad we've come to that conclusion ^

[Tony D]

It's amazing how the first question asked... the one that would shed obvious light was totally ignored.

 

I mean, really guys... You've told us everything but what we asked!

[herhuskyZ]

I wanted to get back to you guys before a week went by like the last time, but obviously I completely failed on that one so I’ll try and make up for it with a mega post with ALL the details.

 

Tony D, on 27 Jul 2014 - 04:31 AM, said:

 

Because a device simply has three LED's on it doesn't confer any similarity other than there are three LED's. Note the MS are all red. They indicate status of different circuits. Yours are Red Yellow and Green, indicating a 'good warning caution' sort of progression. Something checking one variable. 

 

You’re absolutely right. Assuming 3 LEDs meant anything was a bit of a ridiculous assumption. The real reason I started looking into that avenue at all was the CAT5 port on the side. I figured ecu tuning profiles were probably the only thing someone would want to upload onto a box in their car.

 

 

On a more positive note, I went ahead and tore everything apart over the weekend so here’s what I found:

 

So first things first, I feel like I owe you guys some back-story on this whole thing. I am apologizing in advance for the huge wall of text coming up so skip to the end if you just want the end result. It was probably around an entire year ago the first time I heard the beeping. After searching through the car a bit, I found the previously shown box resting inside the center console.

Tony D, on 27 Jul 2014 - 04:31 AM, said:

I don't think it's ignition related at all, more likely some sort of Alarm interface.

 

 

 

This is the same conclusion I came to at the time, figuring it was merely a security device of sorts. Eager to stop the beeping, I disconnected the power to it and the car still seemed to run just fine so assumed no harm done and moved on.

 

But here is where the story started to get interesting. Fast forward a year and 5000 miles later and I start noticing serious emissions problems and initially suspected an exhaust leak. I'm talking a face-full of fumes every time I let off the gas to use the engine's compression for engine braking. Now my mind moved on to fuel control/ ignition timing and I remembered the strange little box I had unplugged a year back. I plug it back in and sure enough, it starts beeping away and that’s how I ended up here. After receiving a couple responses that seemed to validate my belief that the box could be responsible for controlling the fuel system, I decided to go all in and try to figure out just what the previous owners had been up to.

 

First off, here are some more detailed pictures of the board. One thing that I think threw people for a bit loop in my original pictures were the wires. The grey wire came out when I pulled out the box to take its picture.

 

 

 

Using the traces on the bottom, I plugged the grey wire back into the terminal on the far side because that was the connection that seemed to go to ground.

 

Here's a picture of the dash before I took it out (look at the poor heater control panel that was gouged out to make room for a shitty radio/dvd combo player)

 

I see the wires run up the whole center console so this will all have to come out.

 

I always wondered what these switches sitting here were for.

 

It turns out the answer is: nothing.

 

Here is the underside of the console. You can already start to see just how "neat and tidy" the wiring is here.

 

They seem to get spliced together here to light up a set of LEDs on the dash.

 

This is where the lights blink on the dash.

 

Here is where the real fun mess of it all starts. This just seems like an electrical fire waiting to happen.

 

Here I've highlighted where the "box wires" enter the fray.

 

I follow the wires as they go in front of the passenger's feet in the direction of the fuse box. Unfortunately, this grey one seems to head up towards the engine somewhere and this is as far as I am able to follow it.

 

Frustrated at my inability to make any headway through the rat's nest of wires, I decide to call it quits for the day and put everything back into place without putting in the hardware. Later that evening,  I had to reset my internet router, which had a little reset button that needed to be pressed by something tiny like a toothpick. I pressed it and nothing happened so I pressed it and held it down. 5 seconds later the thing clicked right off. All of the sudden I had one of those mini light bulb moments when I realized I had done the same thing to the box's reset button. I ran out to the car, started it up, held down the reset button for 5 seconds, and then voila! The blinking lights and beeping gave way to a silent, single light. I have never felt so simultaneously relieved and dumb at the same time.

 

However, the real moment of truth was still yet to come. I needed to know if my car was still dumping unburnt fuel straight into the exhaust. I take the car around the block and lo and behold, the smell of gas was gone! The exhaust even sounded notably different: less throaty with another sound that I can only think to describe as "intake noise". I could not believe how much I lucked out after failing at my attempt to fully trace the thing.

 

Unfortunately, luck can only take you so far. Before the week was over, the light in the box went out and the sound of the exhaust changed again. The smell didn't come back, but it did take thousands of miles for that to happen last time anyways. My best guess here is that the wires shorted on something somewhere in the jungle of wires so I suppose that is my next mission. Well that and finding out once and for all what this thing actually is.

 

So there you have it! Thanks for reading through that massive monologue and putting up with my incredibly delayed post schedule. Again, thanks for all the help everybody, and if you have any idea about those crazy wires, please let me know.

[Tony D]

There was a CAT5 port on the box? That would have been a clue up front!

Interesting, I shall. Have to review this closer after work!