I have a question. I've read a few threads in the archive and some say you can use a N/A wire harness, and some say you have to have a Turbo harness. I have a turbo ECU but no harness.

Can someone set me straight here... thanks.

 

do it right, just get a new harness.

 

um i had the same question i've been told that to do the swap correctly you have to get the t2 harness i would just get a new one might cost you some dough but at least you know their shouldn't be any problems.

 

Use the N/A harness. There are only a few things you will need to change on there. If you use the Turbo harness you will lose your alternator wiring, which is on the N/A harness.

T2's have their alternator wiring separate from the engine harness.

 

And how is that doing it right? You're creating ten times more work for zero gain, so your advice is bad. If you don't have at least some previous knowledge of the topic, please don't post.

Only two small wiring changes in the ECU are required to use the NA harness with the TII motor and ECU. As mentioned above, trying to use a TII harness in an NA creates a bunch of extra work. There is nothing in extra the TII harness needed to run the engine.

 

Is there a link to more information on the two wires to change on the n/a harness? Thanks.

 

Here are the differences between the NA and Turbo ECU pin-outs:

Series 4
Pin 1R (LG/B wire) is the knock control unit on Turbos and the power steering pressure switch on NA's. If you're installing the Turbo knock control unit you'll need to cut the wire ~6" from the ECU connector and extend the connector side to where you've installed the knock control unit (which also needs power and ground connections). If you're not installing the knock control unit and you have power steering you'll need to cut the wire anyway, otherwise every time you turned the wheel the ECU would get what it thinks is a knock signal and retard the ignition timing.
Pin 2K (L/B wire) is the twin-scroll solenoid valve on turbos and the split air solenoid valve on NA's. If you're keeping the twin-scroll control system operative you'll need to connect the split air solenoid valve connector to the twin-scroll solenoid valve. If you're not keeping the system operative you can leave it disconnected.

Series 5
Pin 1U (Br/R wire) is mileage switch #2 on Turbos, empty on 5-spd NA's and the AT switch on auto NA's. If your car was an auto you should disconnect and remove the EC-AT control module.
Pin 2M (Y/B wire) is the knock sensor on Turbos and the VDI solenoid valve on NA's. Connect the knock sensor to the VDI solenoid valve connector.
Pin 3N (G/R wire) is empty on 5-spds and the EC-AT control unit idle signal on autos.
Pin 3R (L/W wire) is the boost control solenoid valve on Turbos and the 6PI solenoid valve on NA's. If you're keeping the factory electronic boost control you'll need to connect the boost control solenoid valve to the 6PI solenoid valve connector.

 

Actually, doing it right would be replacing that crusty 20 year old Mazda wiring with a full standalone. No one swaps the TII engine into an NA and keeps it stock afterwards, so it's best to start with an appropriate platform instead of relying on hacks and piggybacks to make it somehow work.

 

^^ very good point Aaron. My bad on my part. But NZconvertible I do have alittle experience since my car came with a T2 swap with a n/a harness and it was all ghetto riged. After seeing the few things you have to do to make a n/a harness work on a T2 I feel that getting the right harness is the only PROPER way to do it.

 

But if you use the T2 harness on an N/A car, you would have to deal with the alternator wiring/charging system. On the N/A, it's on the engine harness. On the T2, it is on the driver's side body harness.

 

I just deleted my first response to the words **getting the right harness is the only PROPER way to do it.***** Cursing is verboten around here.

See the posts just above this one for why. The wiring on a turbo EM harness does not match the FRONT harness on a non turbo series four car. A simple look at the wiring diagrams and the plugs that mate b/t the Front and EM harness tell the story.

*Getting the right harneess* is bunk. As close to the *right harness* is the stock n/a harness. Talking series four.

And there is another wire *problem* not mentioned in the NZ short list. It's the wire for the Air Bypass Valve. Both n/a and Turbo have this valve, but on a n/a it's on the left side of the engine and on the turbo on the top right. Talking harness length. But then again, most people (other than me), delete the Air Bypass Valve all together.

Standalones are for people who can't make adjustments to two smal wiring details. They buy a standalone and open the box. The wiring harness just jumps out of the box and falls in the engine bay all by itself alone and EVERYTHING that functioned on the original car now works and works better. No thought involved. Just open the box. Make sure the hood on the engine is open so it can access the engien bay.

And I've been there/done that on the swap b/t non turbo to turbo using a n/a harness. A walk in the park.


Jesus H Christ! Give me a break.

 

Correction. Air Bypass SOLENOID, not Valve.

 

I see the turbo engine has an extra intake air temp sensor at the throttle body, will this not be hooked up? Also I have read that if the ecu detects too much boost, it cuts fuel to the back chamber... is there a MAP sensor that I havent noticed?

And lastly, yes or no on the N/A air flow meter.

thanks alot guys for all your help, I'm real excited about the swap. Pulled the na motor out last sunday, turbo motor will be set over in the car on saturday

Still have to get a FMIC and piping. I also think I'm going to pull off the metering oil pump and premix... Since I work at a marine service shop I have alot of tcw3 oil available.

 

You mean like you did? That seemed to work. Standalones are great, but they're in a whole different league to the very minor changes required to use the NA harness. And there are hundreds of mildly modified genuine Turbos driving around on stock ECU's quite happily, and the end result of doing this is exactly the same as all of those cars. I remember you once saying people are far to keen on saying "go standalone", without appreciating the cost and work involved. A simple engine swap doesn't justify a complete EFI system change. That's determined by what else is planned for the engine, which might be a little or a lot.

Your experience with someone else's bad workmanship has absolutely no relevance on what's "proper". The fact is you will have to do a hell of a lot more hacking to use a TII harness in an NA, and there are absolutely no benefits from doing so. It's just extra cost, extra work, and assuming you do it all right then the end result exactly the same as it would if you'd kept the NA harness. Anyone with even basic electrical skills (and a little pride in their workmanship) would be able to make the few minor changes easily and without any of them being visible. I bet most of the "ghetto rigged" stuff in your car actually had nothing to do with keeping the NA harness.

I imagine there are a few items that fall into that category. Do the secondary injector connectors reach? Most electrical items on the engine are in the same place on both NA and Turbo engines, but for those that don't the solution is obvious and simple. Anyone capable of swapping and engine should be able to handle it.

Actually that would be Air Bypass Solenoid Valve.

The NA engine has the same temp sensor on the intake manifold.

All FC's have a MAP sensor, and they're all in the same place. You need to replace the NA MAP sensor with a Turbo one, as the NA one can't read boost. You'll also need a FCD if you wish to exceed 8.6psi.

Like the MAP sensor, you need to replace the NA AFM with a Turbo one, as they're calibrated differently.

Basically, the MAP sensor and AFM have to match the ECU used, in this case the Turbo one.

 

Use an N/A harness. I just did a swap with the Turbo harness. While it works, I did have to do a bit of re-wiring. Looking back, I should have ignored the person who said it was recommended to use a Turbo EM harness. Then when it came time to get the car running, and I had to splice a billion wires to get it working, I read HAILERS numerous posts about using an N/A harness and said "god dammit."

 

na harness is easy peasy.

cut two wires at the ecu plug, and then plug everything in.

ait sensor moves from the back of the uim to the tb elbow, but honestly. i dont even have one right now. using a na tb elbow. It likes to flood, but besides that no problems.

car runs great.

 

Here's a picture of the two plugs on the EM harness that connect to the Front harness.

Both n/a EM plugs and Turbo EM plugs mate with each other.....But the function of several wires are different and have to be addressed if you put a Turbo EM harness in a n/a car.

As shown in the pictues, the wires that are different have a ( ) around them, showing the diff b/t turbo vs non turbo at that paticular location.

I never said you can't use a Turbo EM harness on a non turbo car, but you need to address those wires/functions and they represent much more in the way of alterations than to just use the stock n/a harness with a Turbo engine.

I'd bet I could even install a stamalone and get most of the wiring right.

Yes, the secondary injector clips will reach just fine.

 

...

 

Hehe, point taken. I guess I've gotten far too frustrated when dealing with old, hacked up wiring harnesses to consider that the original poster's wiring harness might actually be in good condition. To me though, an engine swap to a different engine is reason enough to go standalone if the owner intends on upgrading the new engine...which, lets face it, 99% of them do.

'Course, it's another story if the owner of the car has no hope of wiring up a standalone properly.

 

can you PLEASE explain these??? i understand that wires need to be changed, but i dont know wich ones (ie: i dont understand how to interperet that picture...)

 

Read post #7 in conjunction with the ECU info in the FSM Fuel chapter.

 

ok, im looking at in now, but im not sure what im supposed to be looking at...

 

I listed the the wires at the ECU that need to be changed in post #7. The FSM will show you where on the ECU connectors those wires are.

 

ok, gotcha, i will have to look for that then.