DIY: Installing an injector resistor box

Your premier source for information on the Turbo KA: KA24E-T and KA24DE-T (KA with aftermarket turbo kit)!
User avatar
fiznat
Posts: 6284
Joined: Sun Sep 15, 2002 10:15 am
Car: Grown up :(
Contact:

Post

How I set up mine, using a DSM resistor box:

Each injector has 2 wires on it, a red (power) wire and a different color (ground) wire. (The colors are different so that you can look in the manual and find out which gound goes to which cylinder. Mixing these up will cause you huge problems.)

If you look on the wiring diagram in the FSM, you will see that a short distance from the injectors, each of the power wires for the individual injectors combine into one single power wire which goes directly to the ECU. It is easiest to install the resistor box if you find this spot first.



Note again this is the factory wiring where the 1 wire splits into 4 for each of the injectors. This spot is right near the information plate on the firewall of the engine bay. You can see that I cut the power wire a few inches back from the point where it splits. This is where I will install the injector resistor box.

The DSM box has 5 wires on it. 4 black wires which go to the individual injectors, and one white wire which is the power source. Attach the black wires to the 4 red wires after the split in the factory wiring, as shown, and the white wire to the ECU SIDE of the factory red wire (to the left as you are looking at the engine) Notice how the resistor box now takes power from the ECU, and sends out 4 power wires to the injectors:



Note that you should not be using butt connectors like I did... You SHOULD be using good solder connections, I was lazy

It does not matter which of the black wires goes to which of the 4 red wires... all 4 supply a constant 12 volts to the injectors, so it does not matter if you mix them up at all. (Note the same is NOT true for the colored ground wires, which need to remain in a particular order. You should not mess with the ground wires at all during this install!)

Last step is to mount your injector resistor box and tape everything up nicely. It helps to use wire loom as well to make everything look uniform.



Viola!



User avatar
hannibal
Posts: 9683
Joined: Wed Sep 11, 2002 2:38 am
Car: Red Line to Glenmont
Location: Washington DC

Post

Foster, youre the man. Ive never seen a write up on this, and it turns out to be very simple. Thanks for sharing!

Maybe this should be added to the injector sticky in the future...

Tictakman
Posts: 757
Joined: Wed Oct 23, 2002 2:42 pm

Post

where did u get the dsm injector box?

Zak

User avatar
fiznat
Posts: 6284
Joined: Sun Sep 15, 2002 10:15 am
Car: Grown up :(
Contact:

Post

Thanks!

I got my box from Ivan at phatka-t, but they can be had of course from a DSM dealer, from a junkyard (these boxes are in a lot of DSMs I noticed), or possibly from a regular auto parts store.

There are other types of resistor boxes of course-- as well as the single type that you wire inline. The process is pretty much the same for any type, just cut the power wire, add the resistor, and attach the wire back. Pretty simple

Tictakman
Posts: 757
Joined: Wed Oct 23, 2002 2:42 pm

Post

is this possible....instead of wiring in the box with 4 separate resistors just use one resistor before the wire splits into the 4 separate injector wires? if this could be done wouldnt you just need a resistor that could hold more ohm or whatever?

ZAk

User avatar
WDRacing
Moderator
Posts: 23925
Joined: Mon Nov 25, 2002 2:00 am
Car: 95 240SX, 99 BMW 540i, 01 Chevy Express, 14 Ford Escape
Location: MFFO
Contact:

Post

Added to Sticky!!!

User avatar
onosqv
Posts: 5676
Joined: Wed Aug 07, 2002 12:32 pm
Car: '92 240sx Vert
Contact:

Post

Hoo hoo, cool.

Anyone know how to check if one of these resistor boxes (i.e. the dsm one) is in proper working condition?

I'm sure that would help everyone trying this a great deal, as these parts are usually only available and affordable used.

I'll be installing mine after I get them injector cleaned, THANKS FIZ!

Tictakman
Posts: 757
Joined: Wed Oct 23, 2002 2:42 pm

Post

does anyone have a part number that i can use at autozone or something to get a box. i went there yest and they didnt know what or where to find it. i told them dsm's and old civic's used to run them...

Zak

User avatar
Fenvy
Posts: 5054
Joined: Thu Jan 29, 2004 9:30 am
Car: 2005 350Z Base 6MT

Post

what is the point of this mod?

User avatar
eddiec
Posts: 966
Joined: Sun Dec 28, 2003 11:01 am
Car: 91 S13

Post

to use the bigger dsm injectors.

DRIFTEADOR
Posts: 706
Joined: Thu Dec 16, 2004 6:17 am

Post

check the resistance between power and injector leads, black and white. should be ~8-12ohms.

go get one at a junk yard, theyre cheap. found on obd0-1 preludes, obd0 civics, crxs, and integras, as well as g1 and g2 eclipses.

as far as I know, no one makes saturated/ high impedence injectors bigger than 550cc, so if you need more fuel you have to get this. theres no performance gain or anything just from switching to peak and hold.

dsylvia
Posts: 113
Joined: Mon Jan 24, 2005 7:10 am
Car: 93 hatch
Contact:

Post

resistors and resistor boxes are used mostly when using 50lb, 72lb, or 96lb. msd or other top feed injectors.

the impedence of the bigger injectors is different then stock and will not work properly without the resistors.

FIZ nice write up, quit being lazy and solder them dam wires, lol.

User avatar
Edub1
Posts: 1931
Joined: Thu Nov 10, 2005 2:20 pm
Car: 89 240sx KA-T

Post

Pictures not working. Where do you get one of those? I found a 95 DSM non-turbo. Is it the big aluminum box next to the ECU behind the air cleaner box?

Nobody seems to even know what they are.

User avatar
emperor_lunchbox
Posts: 1305
Joined: Sun Feb 22, 2004 6:31 am
Car: 91 240sx, 96 eclipse spyder, and 96 camaro z28 (For Sale)

Post

pics not working for me either

User avatar
Iamjohnhayes
Posts: 411
Joined: Mon Apr 25, 2005 9:42 am
Car: 89 Single Cam Hatch

Post

check the dates on this thread it is comming up to being a year old. the pics prob dont work because they are no longer uploaded where ever he had them hosted anymore.

+ for bring up old threads

j-z
Posts: 2878
Joined: Mon Dec 01, 2003 4:26 pm
Car: 95 240sx

Post

yeah its like a 4''x3'' silver aluminum box with what looks like cooling fins. the wires go to the fuel rail and then to each injector.

User avatar
Edub1
Posts: 1931
Joined: Thu Nov 10, 2005 2:20 pm
Car: 89 240sx KA-T

Post

Man, I swear I think I was looking right at it. I couldn't trace the wires between the box and the injectors though. It was behind the intake box and what looked like the ECU. We need a DSM guy to tell us where TF this thing is. Does the non-turbo have them?

User avatar
fiznat
Posts: 6284
Joined: Sun Sep 15, 2002 10:15 am
Car: Grown up :(
Contact:

Post

Soooorrry guysss!! All my DIYs will be fixed tomorrow (Easter Sunday) I swear!!

User avatar
Ezzo
Posts: 170
Joined: Wed Mar 08, 2006 4:14 pm

Post

please excuse my thread necromancy but if anyone has a backup of the pictures it would be a great help.

User avatar
jpadilla12
Posts: 35
Joined: Mon May 22, 2006 4:46 am
Car: 240sx

Post

Go to Turbo240 and check out the forum under tech. They have the resistor install there.

User avatar
WDRacing
Moderator
Posts: 23925
Joined: Mon Nov 25, 2002 2:00 am
Car: 95 240SX, 99 BMW 540i, 01 Chevy Express, 14 Ford Escape
Location: MFFO
Contact:

Post

Ezzo wrote:please excuse my thread necromancy but if anyone has a backup of the pictures it would be a great help.
I'll get Fiz on it...

User avatar
Ezzo
Posts: 170
Joined: Wed Mar 08, 2006 4:14 pm

Post

awesome, I didn't even know AMS/turbo240 had a forum. good to know. thanks for the link.


Return to “KA24ET / KA24DET Forum”