im doing a s4 na to s4 t2 swap and i have the ecu, s4 t2 wiring harness with all the sensors and the motor. the harness is still connected to all the sensors onthe motor i want to drop the engine with the t2 harnessalready on the motor and jus connect it to the t2 ecu. is there any wiring i have to do to get it to run or is that all i have to do?

 

No, do not use the TII engine management harness; it's a waste of time. Click the link in my signature for all the info you'll need for the whole swap.

 

not sure if S5 is the same but the T2 harness on mine made it the easiest swap ever

 

It's still more complicated to use an S5 TII EM harness on an S5 NA, than to keep the NA harness. The NA harnesses swap over extremely easily.

 

You say its a series four car so use the non turbo harness on the engine.

The reason is that there are two ORANGE colored elect plugs in the passengers foot well that mate with the Front harness. The wires in the Turbo EM harness do not have the same purpose in life as the wires in the Non turbo EM harness (still talking about the ORANGE colored plugs).

I attach a jpg of someones elses EM harness and the ORANGE colored plugs as a ref.

The two jpg attached called X-15 and X-16 are those two ORANGE in color plugs.

Look at X-15. One half of the plug is colored RED and is a part of the FRONT harness. The black/white half of the plug is on the EM harness that goes on the engine.

See all the wires with a ( ) around them? Those are peculiar to a Turbo car. Your EM harness is composed of all those ( ) wires plus those wires in other sockets that have no ( ) around them.

So your going to be mating wires with ( ) around them with wires in the Front harness half of the plug that have no ( ) around them. Those wires with no ( ) around them will be mating with wires with ( ) around them.

Wires with ( ) around them have different functions than wires with no ( )around them.


There. That ought to confuse everyone.

NOWHERE above did I say you can't make a Turbo EM harness work with non turbo Front harenss. Just makes for a lot of work for no gain.

 

So, I attached three jps of the same plug X-15 and wrote what each ( ) wire does in life.

So in the first jpg you look at the black/white half of the plug which represents the EM harness and you see the (YW) water temp wire for the turbo car. Now if you mate both halves of the plug i.e. the Front to the EM half, you end up having the (YW) going to a socket on the Front half of the plug with no wire. Gee, that's not going to work out to swell.

In the second jpg you'd hvae a G/B aux fan wire in the EM half mating with??? no wire in the front half of the plug. Not too big a deal if you don't care if the aux fan temp sw works or not.

In the third jpg I showed the (BrR) and (BrB) wires in the EM half of the plug. Now look at the Front half of the plug where those two wires will be mating with wires with no ( ) around them. Those would be the BW and WB wires. Well the BrR is from the boost sensor output wire and if you mate the plug halves, then you'd have the boost sensor output signal which is NEVER over 5vdc mating with a BW wire that goes directly to the ENGINE fuse which has batt voltage of up to 14.5 vdc on it with the engine running. Duh. Not good because the BrR splices off to pin 2B on the ECU which NEVER should see anything above 5vdc and mostly figures in the 2-3vdc range. Not a good thing to do.

Then you'd have the BrB boost sensor GUAGE gnd wire going to the WB wire that makes it's way to the alt relay coil in the CPU. Not a good idea.

I didn't do X-16 'cause I'm lazy and also couldn't remember a couple of the wire functions off hand. But while I'm here, you'll see a YB wire in the FRONT half of X-16. That is the water temp wire going to the water temp gauge......but remember that the YW wire from the water temp sensor in the EM half of your plug is in X-15.....that OTHER orange plug. So you'd end up with half of the water temp signal wire in one plug and the other half of the signal in the other plug. Not desireable. Fourth jpg is the X-16 again.

 

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sorry to bring this from the dead but would it be easier to use the s4 dash harness and engine harness for a s4 turbo II swap or change both harnesses from my s4 turbo II parts car? Does the s4 na harness plug into a s4 turbo II computer with no problem?

 

You don't need to change anything for the cluster/dash. The front harness plugs right into any S4 ECU, NA or Turbo, without modification. Click the link in my sig. for everything else you need to know.

 

what about if im using the turbo II guage cluster its in alot better shape then mine so ima use it.....will all the guages work ok? (wont be upset about the boost guage not working cause it wont be used)

 

my swap was a success. it took me a total of 3 days to do. i used the na harness and it started first time i turned the key

 

I think everything will work, except the boost gauge. You can compare the NA and turbo in the wiring diagrams section of the FSM. If you have not downloaded these, go to the forum FAQ.

 

ok thanks for your help man

 

two more questions forotary rocket....will the na harness work for the tII manual trans? and also I am doing the exact same setup on my car as yours an i was wondering if you have had your car on the dyno or at the track? Also how much boost u runnin?

 

The engine management harness has nothing to do with the handful of switches on the transmission. The engine harness is the only one that connects to them, and you would be leaving it as is.

No, it hasn't been on a dyno yet, and I run 12 psi.

 

few more questions. My na car that im doing the swap into has the injector resistor box in the engine bay (manufactured 3/87) and its wired into the na harness that i will be using. However, the engine, turbo harness (wont be using), and computer were from a car that didnt have the injector resistor box. I know i have to swap the injector clips because they are different but what else do i have to do to make it work? Do i just leave the resistor box unplugged? Any help is appreciated cause i dont want to fry my ecu or the injectors.

 

Your TII injectors should be high impedence, since the harness lacks the resistor pack. You can test them with an multimeter meter, and they'll be about 12-13 ohms. Of course, the offset will be different as well, which is why you either need to carve a slot in your existing injector clips, or splice in the TII ones. You can then remove the resistor pack completely. For it's plug on the harness, cut 5 short wires and connect them to each pin on the plug. Now take each end and solder/crimp all 5 together. If you skip this last part, none of your injectors will be powered. By jumping the plug, you are bypassing the resistor pack.

Here's a thread on it: https://www.rx7club.com/showthread.p...hreadid=158594

 

thanks youre the man....if u ever come to wilm, nc ill buy you a beer lol My injector clips on the na harness are in rough shape anyways so ill just solder in the other clips. Ill grab my multi-meter and go check it out.