So I'm working on my FD trying to wire up my speedo and tach as part of my 2JZ swap, and I've discovered that my entire gauge cluster appears to not be working.

The gauges light up, but no gauges work...even the gas gauge itself is essentially bottomed out, I've noticed.

Looking at wiring schematics and various web-sites I'm finding that there appears to be only one ground signal wire for the entire gauge cluster, on connector "X-14".



The "B" in the bottom left is the ground signal wire I'm referring to.

- So some questions I have are:

1.) Should I consider splicing that ground wire to a new grounding location? Maybe during my swap process, the old ground location is no good now.

2.) Are there any other wires I am forgetting? Are there any other 12V power signal wires that I am missing that I should be looking at?

I've taken the gauge cluster out to examine it myself and the only thing I noticed was one of the screws was missing. I replaced it with an aluminum screw without a copper washer...could that be a problem? Is the gauge cluster that finicky, perhaps that the screw NEEDS to have copper washer? Here's how it looks:






While the car was in the shop last year for a few months, they re-flowed the solder on the back of the circuit board because they reported it as having some intermittent connectivity issues due to corrosion and some "cold-solder".

So yeah...

Any thoughts or suggestions?

What about fuses?

Are there any simple things I am just totally spacing on, here?

Thanks, guys!

 

The ground you're suspect of in X-14 is definitely what I'd put my money on. Like you said, it's the primary ground for the cluster and if you're doing an engine swap without your emission harness (you won't keep it as its basically the engine harness for the stock FD), you'll have to ground that wire out yourself. On the stock FD, that wire gets passed to the emission harness and it grounds on top of the stock engine. When you swap an engine and ditch the emission harness that ground wire just sits in X-14 unterminated.

Good luck
Lane

 

i second the checking of the ground. on my first v8 swap, i ran for a few years without a speedo nor tach... i thought I had everything wired up correctly... then I went back and re-read the guide I was using and noticed I left off the ground in X-14... plugged it in and my tach worked (i had other issues preventing the speedo...) but I think because I had ran for 2+ yrs without the ground, my tach wouldn't go over 4k...

i cut the ground wire going into the connector and spliced in an extention then bolted that to my chassis...

the x-14 is tucked up behind the glove box on the passenger side of the dash... it tends to hang out along the firewall... if you find where the emissions harness comes through into the cabin of the car, go a few inches towards the drivers side.

 

Awesome. I'm glad we're all thinking the same thing, and thank you lt1_rx7 for confirming that wiring up that ground made your gauges work. That's super encouraging and let's me know I'm on the right track.

I'm gonna go ahead and cut/splice that wire and just run it straight to a known good ground point or an existing ground wire from my 2JZ harness and see if that works!

I will update this thread and let everyone know if it works so that the NEXT person who has this same issue and finds this thread will actually have a definitive answer. lol

Thanks guys!

 

How are you sending pulses to your tach? The FD tach needs 2 pulses / rev to scale properly. Sounds like you're sending it 1 pulse / rev.

Lane

 

Well, for you V8-swapped FD guys it's easy because according to Granny's Speedshop web-site: http://grannys.tripod.com/3LS18.html

"...The stock rotary engine put out a tach signal that was the same rate as a 4 cyl piston engine. The LS1's PCM puts out a 1/2 rate tach signal for a V-8. Simply using the LS1's tach signal to drive the RX-7 tach will result in a correct reading tach."

Where-as with the 2JZ, if I want to avoid having to buy the Dakota Digital SGI-8 Tachometer adapter, I know that I CAN manually configure the pulses/rev through the AEM Tuner software, but through my web-searches I haven't found anyone provide 100% clearly-defined AEM Tuner configuration settings for making the tach work, so I'll likely have to tinker around with it a bit myself.



That's the default 2JZ setup in the software.

I know I have it wired correctly to pin 38A which is the LS7 (TACHO Out) signal according to the AEM manual, but again I will likely have to tinker around with the AEM Tuner settings to get it to work just right.

Input/advice is certainly welcome.. lol

If it gets to be a big enough PITA, I might just buy the stupid Dakota Digital SGI-8 Tach Adapter.

I already have the SGI-5 Speedo Adapter....lol

I actually bought two of them by accident, if one of you guys needs one... $50 shipped. haha ;P

 

YoshiFD3S - That question was more directed at lt1_rx7 since he was the one mentioning that his tach wasn't scaled properly and it sounds like the reason is due to his pulse/rev setting.

For you, you need to get your tach working before I'd worry about pulses/rev
If you can get it reading anything, it should be obvious if you need to add or subtract pulses/rev from the AEM. As far as how that's setup, I wouldn't know as I've never owned a AEM but I do agree with you; there should definitely be a place to set it up.

Like your Granny's documentation alluded to, LSX V8's are the exception as they output 2 pulses/rev by default, which is ideal since the FD's tach takes 2 pulses/rev natively. LSX guys can get easily get themselves into trouble though since pulse/rev can be adjusted in the popular tuning software packages.

Just remember, most V8's = 4 pulses/rev, V6's = 3 pulses/rev, and 4bangers = 2 pulses/rev by default. If you setup your 2JZ, it's default is most likely going to be 3 pulses/rev which you'll need to correct to properly use the FD tach, but like I said, it should be obvious what you need to do once you resurrect the tach.

Lane

 

Interesting...

I e-mailed AEM about how to configure the AEM software for the Tach and got back this response:

I guess once I get my gauges working I'll find out if he's right or not, won't I? lol I'm not sure if he understood my question, though..

Yes, that configuration is correct for a 2JZ-GTE...but is it correct for converting a 6-cylinder (3 pulse/rev) to the rotary (2 pulse/rev) tachometer?....Doubtful... lol

Either way, I'll post updates in here and in my "official" Build Thread (signature) as well if you guys wanna stay tuned.

Thanks again for all your help.