Tach signal?

[240slidekat]

i have a 89 240sx with a RB25det on it. im finishing up everything and everything works EXEPT the tach. i have the tach and safc2 spliced into #7 pinout but i dont have any readings at all. i checked the ecu wire and i am getting a signal from it. I had also searched the forums and from what i have read people have used a 10k Resistor.

I just want to make sure that the resistor method works. has anyone tried this?

[armysweitzer]

ahhh im in the same boat, it seems nobody really has any good answers. It seems with sohc wiring its a PITA but hopefully someone will chim in. Are you using a r32 tach or a stock usdm 240 tach?

[240slidekat]

im using the stock tach but i am going to use the safc2 as my tach.

[kickboxin]

I had to do the resistor trick. It worked to get my aftermarket tach working, but my gauge tach in the cluster isnt. I have to pull it out one day to check it. I have a rb20det in a 89 s13 (sohc cluster)

[Kansei240sx]

I did it to my RB25. You have to pull the gauge faces off and the needles off as well, and inside there is a variable resistor, and you either turn it all the way to the left or right, i cant remember. Ill let you know when i remember.

But once you turn it you may need to turn it a tad back one way or the other to get it properly calibrated. Its almost perfectly accurate below 5 grand, once its above that around redline its about 200-500 rpms off, depends on your cluster.

420th post... lol.

[NightKids2]

I still havent found a way to get mine working. I purchased a MSD DIS Tach adapter, but I havent had the time to install it.

[Bluefire]

Those with 89-90 240's having problems with the tach not working, need to swap the tach out with one from a 91-94. Tach will not work with a KA24DE, SR, or RB swap. Once you swap it out then you can try and figure out how to switch it from 4-6 cylinder...

-Bluefire

[240slidekat]

yea im going with a rb cluster

[RB13sKi]

how hard is it to wire up the rb cluster

[s13_rb25det]

I did it to my RB25. You have to pull the gauge faces off and the needles off as well, and inside there is a variable resistor, and you either turn it all the way to the left or right, i cant remember. Ill let you know when i remember.

But once you turn it you may need to turn it a tad back one way or the other to get it properly calibrated. Its almost perfectly accurate below 5 grand, once its above that around redline its about 200-500 rpms off, depends on your cluster.

420th post... lol. <IMG NAME="icon" SRC="http://images.nicoclub.com/forums/image ... smoker.gif" BORDER="0">

could u maybe please try to remember

and did u have to install any resistors, or just turn the variable resistor (is it positioned around the area of the REVs or Speedo?) ?

thanks,

nico

[Valley]

the variable resistor is on the speedo if i'm not mistaken.

i too have a 89' rb25, i never gotthe stock tech to work, i swapped out the entirecluster for the rb one, its not hard, just about 3 hours with crimp butt connectors and looking at the back of both tachs... if i'm not to busy working on my own car i may make up a sohc to rb cluster.. who knows..

[kickboxin]

Ok.. I got my tach to work last night. I have a 89 240sx with a rb20det. I had to do a few things:1. 10k resistor on the tach wire. This I had to do to get a tach signal for my aftermarket tach

2. Used a dohc tach gauge from a dohc cluster. Put that gauge in my sohc cluster.

3. used a tach adapter like the link below to convert the 6 cyl pulses to a 4 cyl pulse like the tach is looking for:http://cgi.ebay.com/ebaymotors...30745

When comparing the tach in the gauge to the megan racing aftermarket tach it is just a little off. It starts off a couple hundred rpms below the aftermarket and around 6k it is about a couple hundred over the aftermarket tach. Close enough for me!

[blues14]

you can send your cluster to LS auto and they will convert it to properly read the 6-cyl signal. do a search for Ls automotive.