Hey, when i plug in my Calum R/T my tach stops working.. but when i switch back to the stock ecu it works.. is there something i need to do in order to get the tach to work:???>?

LMK

What car?

I'm not sure how the tach is wired, but I am running a real time and my tach works, with no mods or pin switching.

91 240sx ka24de..

anyone...... is my ecu bad then??? how hard is it to disassemble the ECU and solder it into another~....

It's easier to just replace the tach driver on the ECU. I'll take a picture this evening. Can you solder?

no but i have a friend who solders chips for a living... :biggthump

Awesome. I think I've posted this before, let me see if I can dig it up. It's not really that hard.

Found it- the S13 ECU is the exact same as the B13. You will need a junk core ECU to pull the part from (I bet any early 90s Nissan ECU will have one somewhere), or I'll look up an equivalent part you can buy from Radio Shack.

http://www.sr20forum.com/calumsult/214429-q457-runs-tach-b13-ecus.html

This is a really really easy fix on a B13/S13 ECU as they used a simple discrete part. You can do this with a simple soldering iron and a little solder wick, no fancy tools needed.

Just for reference for anyone that runs accross this thread, this is the B14/S14 equivalent (slightly hard to replace)-

http://www.sr20forum.com/calumsult/214429-q457-runs-tach-b13-ecus.html

Ok, for the B13/S13 this is the datasheet for the part that needs to be replaced-

http://www.classiccmp.org/rtellason/transdata/2sd1922.pdf

You can't source this part new from any of the convenient suppliers, but it's not really a big deal. You can either pull one from another core ECU or you can replace with an equivalent part. If replacing with a new part the only part the only pain is that the collector is the center pin, so that limits your choices. Either of these will work-

http://www.mcmelectronics.com/product/2SD468&cid=prodCrossSell

http://www.mcmelectronics.com/product/2SD789&cid=prodCrossSell

...and both are less than 50 cents. Might as well order several if you go that route.

Because of the odd pinout this part uses I can't find a Radio Shack replacement. If you guys come up with something please post here.

cool thanks dude..

I found Q457 it is has bubbles on it lol

... well anyways it looks like it got stuck to d463 when it burned out. the one next to it... what is d463 and should i replace that too?????

Did the core come from your car? If so you'll want to figure out why it blew in the first place when you fix it. It's usually from people installing an aftermarket tach incorrectly (connect the power line to the tach signal and *poof* out comes the magic blue smoke).

D463 is a diode. Your buddy can test it without removing it if he has a multimeter with a diode test function. It's not on the same circuit as Q457 and was probably not damaged. I can't tell what the p/n is for that diode, but any generic power diode will work. I would use something like a 1N4001, but Radio Shack will stock this, or scavenge one from another core. If you want to size D463 correctly just measure the resistance of the S.C.V solenoid, calculate the current, then size the diode to a little larger than that. It can't be all that much though, they didn't use a particularly large body diode. Your probably fine with any diode that is like 1A or more.

D463 is part of a circuit that isn't used on the B13, it's only used on the S13- it's the S.C.V swirl control valve solenoid driver circuit. If this circuit is damaged you probably wouldn't be able to tell driving the car- this controls the butterfly valve in the intake manifold on the S13 KA engine. If you've swapped to a S14 intake manifold/engine you don't have this anyway btw, this is a S13 thing only.

I got a spare s13 ecu that i am gonna take the "Q457" from.. i took out my butterfly valves and the swirl control valve so ill prob just leave D463 Alone..

Thanks agian Calum!

Bump, does anyone have the link for the b14 ecu? My tach driver fried this morning, no diea why.