I know somebody here has the wiring diagrams for the dash, so post 'em up!

I found this: http://www.stealth316.com/2-stim.htm

but it doesn't have any wiring diagrams. I'd like to test the speedometer to see how "off" it is. The tach is off by a lot, at 1200rpm for a v6, it is reading 1600rpm. I'm not sure if they use some wierd tach signal like 2.25 pulses/revolution? I'm looking into recalibrating it for a V8 anyways...

I have a huge 38 meg PDF with all the electrical info that I had received from Riceburner some time ago but I don't have a website to host it. Suggestions??

Nolan

That's a good question. I'll see if I can find something

OK, I'll give it a try.

Nolan

Thanks! Has anybody else tested the tach for accuracy? I'll have to sweep through the range to confirm my findings...

I can't get the file to upload past 18%.

And what's the solution for the speedo?

Looking at the rear of the speedometer, there are 4 terminal screws. Left top is the signal input, left bottom is +12, right bottom is ground. I have no idea what the 4th one is for, which was throwing me off. Here is data on the signals used:

Tach:

RPM    Frequency
1000    35.3Hz
2000    82.4Hz
3000    130.4Hz
4000    178.2Hz
5000    223.7Hz
6000    270Hz
7000    322Hz
8000    372Hz
9000    420Hz

99.99% correlation, RPM = 20.803(Hz)+298

For the Speedo:

MPH    Frequency
40     39.5Hz
60     62.1Hz
80     84.0Hz
100    106Hz
120    129.4Hz
180    199Hz

99.99% correlation, MPH=0.878(Hz) + 5.92

I believe I have found the charge pump circuitry, so the tach can be recalibrated for I4 or "true" V6 or V8... The stock v6 must put out some wierd signal, like 2.5 pulses/rev or something.

OK Here's a link for the Electrical PDF:

http://www.uploading.com/files/24YQY84D/92_96_3KGT_ELEC.pdf.html

Have at her!

is 700 pages really necessary?

LOL, I told you it was huge, but it has everything I think.

Nolan

Well, without a datasheet on the SE094 Nippondenso chip, I think recalibrating the tach will be very difficult. I've played with the value of the cap, and the resistors, and the scaling does change, but it always makes it non-linear. None of the driver chips I've seen follow a similar circuit, so I have no idea how to modify it. Sooooo..... I think I will need to create a new tachometer board using a common air core meter driver. Luckily, it will be relatively simple, and cheap. I can probably transfer a lot of the parts to keep the cost and "new parts count" down.

Doh! Sorry to hear that... I just figured it was set up for a "Normal" pulse from a V6. That really does blow. Guess it would be possible to physically attach the Fiero's tach driver and air-core movement to the 3KGT gauge. I hope! I won't have time to look at it any time soon unfortunately. The PDF file is so big because it has all the years from 92-96. Tons of info in there, unfortunately it's the usual stuff like instead of having the entire pinout of the Instrument cluster on 1 page, you have to go to the brake light page for that light, the speedo page for that, the xxx for xxx... Kind of a pain, but good info if you need something specific! I have scans of the pinout info I did of the instrument cluster somewhere if it's of interest? Just traced out all the idiot lights and such.. edit - found a pic of when I was installing the gauges... I don't know if I actually had the Tach connected or not, but it's showing a reading in the pic... I swear my brain's fried. I drove the thing for a year and I can't remember if I had the tach working, that's bad!


------------------
Bob Williams
Working on the next 3800 swap.. Missing the one that worked!

[This message has been edited by Riceburner98 (edited 08-30-2006).]

pinout info would be good. It will take hours to sift through the 700 page manual.

I admire the intelligence and persistence you guys have for interfacing japanese gauges to an american car... it makes the firebird conversion look like child's play.

My brain hurts just thinking about it

Ryan...Man you play with the coolest sh(stuff). I'd love to pick your brain for a few hours. I've been in the "industry" for a long time now, and man, you've got talent. You make my my swap look like Mickey Mouse crap. I'll be watching this thread (like all your others) like a hawk.

Bob

...will these work?

(sorry about the size, but left them large in case it makes it unreadable)

[This message has been edited by Mickey_Moose (edited 08-31-2006).]

What year dash??? I have the electrical manual for a '92 Dodge Stealth, it's the same car as the 3000GT.
I have a scanner at work or I can take digital pics of the pages. Let me know exactly what you need and I'll see if I can help.

Dragon1/Brian

Thanks guys.

Correct me if I'm wrong, but I believe the 91-93 stealth/3000GT dash has a mechanical speedometer, and won't work here?

The 94+ gauges should all be the same, I would think...

quote Originally posted by ryan.hess: I assume there will be some other people out there who want to recalibrate their tach to I4/V6/V8? If I get an assembled board together, that you would just need to swap the meter/face assembly on to, would you be interested? Estimated cost would be about $20, and you could "dial it in". I'll make one for myself anyways...

I'll pay double! You guys have me freaking out ! Resistors, Omz , Flux compacitors I am feeling dumber by the second reading the threads on the topic.....I am wondering if I should not have gotten the 93 3000GT dash. The spedometer on mine is mechanical.

I'd buy one too. And my cluster also has the mechanical speedometer, rats.

Nolan

Yeah, the "ideal" combination seems to be a 91-93 dash (because it doesn't have the airbag door on the pass. side, and the 94+ cluster.

quote Originally posted by cornersonrails: I'll pay double!

Okay, you can pay $40.

[This message has been edited by ryan.hess (edited 08-31-2006).]

WOW, I'll take 2!!

OK, who can dig up a 94 cluster for me??

Humm... The 1st dashboard I got has an electronic speedo and no pass. airbag, but I can't remember what year it was from. The 2nd one had an airbag and an electronic speedo 'cause it was either a '94 or '95. (the one with the stereo controls on the 'wheel) I wasn't even aware there was a mechanical speedo! I love making electronics and all, but I'd pay $20 to not have to work on that issue myself. As for the cluster, there's a '94 on eBay right now for $25 + $15 shipping. Not too expen$ive...

and there's a cheaper one... I sent him the link. I guess he has to worry about canadian shipping.

Thanks for the links. Maybe it's US shipping that I have to worry about. Occasionally there are sellers that don't want to ship to Canada but it's no big deal really.

Thanks
Nolan

Bought enough parts for 5... Those chips are hard(!!) to find. I should have a proto put together in a few days when they get here. I'll let you know how that goes.

Ryan.. what chip did you end up using?

CS8190 was the only one I could find. LM1819, CS4121 and others were pretty much gone.

Where'd you get the chips? Digikey? I'm still trying to find a place that sells the CS4122 or SA5778 (the Philips equivalent) before I bump down the coolness level and get a CS8190 for my custom tach project.

I think I got them at either Arrow or Allied. I can check if you want. It started with an A I know there was a $40(?) minimum order per item, or they would tack on some outrageous fee. So if you're planning on buying the 8190, plan on buying 10 Digikey and mouser don't stock them.

I can't imagine a tach being a single coil type. That's cheap, even for GM! The 3000gt tach uses the standard sine/cosine coils with a spring return to zero. (so you save the 2000uf return to zero cap in their app note)

I have a GM tach and speedometer from a 91 Grand Am right here and both meters look exactly like a galvanometer. The speedometer on my Fiero, on the other hand, looks like a typical air core meter.

quote Originally posted by ryan.hess: Digikey and mouser don't stock them.

Digikey has them minimum qty 1, $4.24 each. They're in stock.
Arrow is probably where you got them; they tack on a fee if any line item is less than a certain amount.

[This message has been edited by Steven Snyder (edited 09-03-2006).]

quote Originally posted by Steven Snyder: Digikey has them minimum qty 1, $4.24 each. They're in stock.

hahaha... how in the hell did I miss that? I had to buy 10

what's sad is I had to buy the rest of the parts from digikey...

[This message has been edited by ryan.hess (edited 09-03-2006).]

quote Originally posted by ryan.hess: hahaha... how in the hell did I miss that? I had to buy 10 what's sad is I had to buy the rest of the parts from digikey...

I will buy some from you if I can't find any of these serial chips.

Go figure, the digikey stuff got here yesterday, but the arrow stuff was shipped UPS and won't get here till monday.

Good news... I ordered more stuff from digikey, and go figure it got here before the arrow stuff. I ordered a chip from them, so I was able to play with my prototype today.

Great news - it works perfectly. I had some issues with a swapped component, and I ended up removing the return to zero spring because I thought it was causing the problems... Well it wasn't, but since I removed it before I figured out the problem, I don't know for sure that it won't cause a problem... In any event, the spring's torque should be linear, so it shouldn't affect anything.

One of the cool things about the mitsu tach, is the redline is at 135 degrees. This makes calibration 100% dead on. So everything up to redline is perfect, after redline is a little off (9000rpm read as 9100 or something).

The components I chose should give enough adjustment room for I4's and V6's as well as V8's of course.