need help sr20det!!!!!

[patsS14]

ok so i bought my 95 240sx and the tach doesnt work because he said they didnt connect a wire and he says its an s13 sr blacktop head with an s14 sr block.. i have ordered an autometer tach with the tach adaptor and when i connected it to the blue/red positive wire for the coil packs my car started to sputter bad. i even connected it to the cas wire and it did the same thing.. so im saying fuck that tach and i want to get my stock on working so if anyone knows how or have any input thanks..

[patsS14]

anybody???? bump

[patsS14]

nobody knows about sr wiring????????

[ultimateirving]

Strange configuration man. That's all. Find out if there is an output on your ecu and tap off there for signal?

[fufanu180]

There is definitely an rpm signal that you can tap into, coming off the ecu. Search for an ecu pinout and find out which wire it Is and be done with it.

CenTex240

[wangan_cruiser]

Check the sr power plug for continuity

[patsS14]

i already tried the yellow/red rpm wire and had no signal then i tried the white 180cas wire and same

[patsS14]

bump...???????

[Kingtal0n]

Do not mess with the white CAS wire.

The normal wire for tachometer signal is the Yellow/Red wire coming off the ECU. Normally it plugs into the dash harness on an S13- but you have an S14 so it goes through the F3 plug along with all the other chassis wires off the ECU.

I dont remember the color on the F3 plug but iirc it is also yellow/red. That is, yellow wire, red stripe. First make sure the yellow/red wire off the ECU goes into the yellow/red wire on the F3 plug and verify the wire location against a pinout for the 95 240sx.

If the wire is connected correctly and the factory tach does not work then you need to investigate further- either the ECU or factory tach or wiring is at fault.

[zombiewolf513]

What ECU do you have: S13 or S14? The colors and pinouts change between years.

Your ECU should definitely give you a signal.

Someone chime in if I'm wrong, the images of the pinouts are off the internet. You can double check an FSM... I would.



The S13 ECU has a yellow with a red stripe wire coming from the ECU that should mate up to the yellow with a red stripe wire on the brown dash connector.

The pin it should come from is number 3 shown in the picture below:

http://www.innovatemotorsports.com/resources/ecu/nissan_sr20det_1991_1995.jpg


The S14 ECU has a blue with a black stripe wire coming from the ECU that should go to the brown dash connector and take the place of the yellow with a red stripe wire on the brown dash connector.

**Zenki ECU**
The pin it should come from is number 7 shown in the picture below:

http://www.innovatemotorsports.com/resources/ecu/nissan_1989_1996.jpg

**Kouki ECU, aka the ECU labeled "NA"**
The pin it should come from is number 2 shown in the picture below:

http://www.innovatemotorsports.com/resources/ecu/nissan_sr20set_1997_2002.jpg


For anyone that wants to know, the S15 ECU has a blue with an orange stripe wire coming from the ECU that should go to the brown dash connector and take the place of the yellow with a red stripe wire on the brown dash connector.

The pin it should come from is number 2 shown in the picture below:

http://www.mys15.org/images/web/ecu2.gif

[patsS14]

i have an s13 ecu.. i followed the yellow/red wire all the way to the plug and it is hooked up fine??? now the aftermarket tach works without the adaptor on the cas wire. idk how accurate it is in high rpm cant drive it yet.. when i cut the cas wire and had the adaptor to it, the car wouldnt start so i connected the cas wire back together and it started. so then i took the green wire from the tach NOT the adaptor touched the rpm wire nothing... then touched the cas wire and it worked..

[patsS14]

when i was able to drive the car the tach would just move up real slow til after like 5 mins its buried all the way??

[Darren]

The white CAS wire will not give the correct signal IIRC, you need to pull from the aforementioned Yellow wire with Red Stripe. I had a tach hooked up to the white wire and it would only go to ~2500 rpm max, even when the motor was obviously going higher.

Also something that has not been touched on here ... I'm sure your car came with a DOHC motor in 95, but if it came with a SOHC the tach will not work, as they are different.

So if it's the case your car came with (or has now) a SOHC tach, ie KA24E motor, you'll need to source a DOHC tach and plug it into your cluster housing.

Hope that helps

[zombiewolf513]

Here's what I want you to do...

1) Take a test light, and with the dash harness unplugged, see if you get a signal from the yellow/red wire coming from the ecu.

If you don't get a signal, the pin is in the wrong place, or your ecu is messed up.
If you do, see number 2

2)Plug the connector back in, and pierce the shielding of the yellow/red wire on the chassis side of the plug and see if you've got a signal.

If you don't, the connector is messed up.
If you do, see number 3

3) check for the signal up at the tach

Post results before cutting away at your wiring even more.