Wiring EMS4 to 01 help needed
 

I need to get my car up and running again. I had the box installed and dyno tuned.The only problem is that the IAC was not hooked up. When it is hooked up it burns out coils (5 so far). In this configuration (no IAC) it is a bitch to start. It is all a long story and I dont want to get into it right now. All that I am going to say is that I am no longer having my coworker help me with this. I will try to find some online wiring diagrams to link to.

The tach didn't work, VVT was not set up, and the IAC would burn up coinls. So this is what I am looking to get help on. I don't have much info at this point since there has been very little comunication about what he has done to my car. So if there is any questions fire them off and I will do my best.

What I am looking to find out is what wire do I have to connect to the EMS to get the tach to work? I have looked online at the wiring diagram and can't pinpoint the correct wire. Also is there a speciffic setting on the EMS that I have to set up?

Is there any thing different about the IAC on thease cars that would cause feedback in the system to burn out the coils. May be having the wrong wire going into the computer or the wrong ground. Just a shot in the dark.

I can live without the VVT for now.

Thank you in advance for any help.

Have a great day,
Jared

P.S. Savington thank you for all your help so far

So I took the cluster out and found that the tach has two sets positive and negative leads going to it on the green plastic on the back of it. I can't find it on the wiring diagrams to save my life.

Anyone have any clue where to start?

Have a great day,
Jared

Verify that you have the following correctly set up:

Coils are 3F(cyl 1+4) and 3I (cyl 2+3).

Tacho is 3O

IAC valve (-) is 2Q, 12V for the IAC valve is 2P.

Anything else, let me know.

https://www.miataturbo.net/attachmen...1&d=1309850982

Thank you. I will check and get back to you.

Have a great day,
Jared

So here is what I have so far. This is just a list I will go and do the wiring later.

Clutch sw 4I
Cam/OCV 4D or 4R
Knock 4A or 4M
Intaks Valve 4J
intake Vent ?

Can anyone confirm or pinpoint thease.

Thank you all for your help.

Have a great day,
Jared

Clutch sw 4I CHECK
Cam/OCV 4D (+12V) or 4R (signal)
Knock 4M CHECK
Intaks Valve 4J (4J is VTCS vacuum switch, the VTCS valve itself is at 2N)
intake Vent ??? Don't know what that is???

Thank you Reverant.

Will I have to run a constant 12v to the OCV?
Intake vent. Refering to the valve that releases the vacume. Which of the two is on the intake manifold near the EGR?

Have a great day,
Jared

No, use the same switched 12V that goes to 4AF to power the ECU. Same goes for the idle valve.

I feel completely dumb in asking this but is the IAC in our cars a stepper motor?

Have a great day,
Jared

No, its a 2-wire solenoid valve (ie it needs a PWM signal).

Here is the 01 wiring diagram. In case that you do not have it.

I do, but thank you any ways.

Have a great day,
Jared

So the only other thing that I noticed besides the IAC and VVt issues is that the engine harness has 2 grounds as does the EMS. They are both wired together. I don't think this would be a problem but you never know. I was planning on separating them so that they are not all 4 wired together. As soon as I get the harness issues fixed and get some coils and this car to my house I will reinstall every thing and see how it goes.

Any thoughts?

Have a great day,
Jared

The engine harness has 4 grounds: 3A (Injector ground), 3B (ECU ground) and 4A (output ground, ie IAC, VVT, etc) and 4O (analog sensor ground). You can connect 3A with 4A without any problems, you should better have the ECU itself grounded through 3B and the sensors must absolutely be on 4O, and nothing else on 4O.

Wow, thank you. That could be where my feedback is comming from! Since the EMS4 only has 2 batt neg. and a sensor ground. What should I wire where?

Thank you.

Have a great day,
Jared

After rereading the last post I don't know what I was thinking.

So I can wire both 3a and 4a to one ground.
Then wire 4O by its self.

From my knowledge sensor ground is for the sensors on the car to ground to the computer.

So that leaves me with one more ground for the 3B.

The EMS4 only has 2 Batt ground.

Can ground 3b be connected to the one with 3a and 4a?

Have a great day,
Jared

Having read this post and the one previous about the same car, do you know if your "feedback" is noise or power being back feed through the ecu? Noise will effect the car all the time where backfeed power will only effect at certain times. Have you verified any concerns? Or what are your symptoms?

F L

Smptoms are burnt out coils.

I don't know where its comming from. Just that it is there. All I know is that it burns the coil at idle with the IAC pluged in. I drove the car for a few days with out the IAC and it drove fine.

I am just trying to get the harness sorted. The guy who I hired won't give me any info. He says that I am the customer and I don't need to know about everything going on.

Thank you for any and all help.

Have a great day,
Jared

Can you snap a pic of that harness?

IAC and dwell really have nothing to do with each other. The only thing that can have an effect if the dwell settings are wrong, when idle speed changes your battery volts may lower just enough to put the coil dwell in a bad spot and fry a coil. I would not be concerned about idle control but with your dwell settings.

Do you have much experience with tuning and standalones? From my experience I have had naggy customers who want to know what every key stroke and what every change is. It can be very daunting trying to sort out issues and deal with a PITA customer. No offense.

I put and EMS 4 on my miata a while back. I did it in parallel with a 36-1 tooth wheel. Out of all of my testing this was the way that it worked best. All AEMs have problems when its power and the harness power are switched from seperate sources. Like the harness can stay on wither ecu off. They tend to do funny things.

F L