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iliasfyntanidis

Vipec i88 wiring

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Hi there.

I am bulding my harness for my Mazda Miata 99 model,with an adapter so i am using my exhisitng engine harness in order to terminate it to my Vipec i88,with plugs A and B.

I have the ECU pinout but i have some leftovers pins from my ECU that i cannot decide where they should go on the Vipec.

1)First my ISC valve has to wires which are 3M and 3Q pins on my ECU.According to Vipec manual

''Two terminal ISC solenoids need only one auxiliary output (or ignition channel) to open the
solenoid. A spring is used to automatically close the solenoid. Connect one terminal to the
engine managements power supply and connect the remaining terminal to an Auxiliary/
Ignition Output Output. The orientation of the wires does not matter.
An ISC solenoid must be wired to a switched power supply.''

 

So if i am correct one of them should go to one Aux input and the other to +14V in Vipec plug A.My ''problem'' is that +14V is used in order to feed the Vipec.Are there any other pins in Vipec's plugs that give +12V output?Can i use the Aux +14V 9/10 on the plug B?

The leftovers for completing the harness are the following.

2)1A Back up power supply(What is that really?)

3)1H Battery positive voltage monitor

4)1O General field coil control

5)1Q Generator warning light

6)1T Generator 

7)3K Fuel tank level

 

Note that the original alternator was controlled by my ECU.I purchased an old type alternator with the regulator build in from an older Mazda Miata.

Attached is the ECU pin out.

Thanks in advance,any help appreciated.

 

 

 

1999_ECU_diagram.pdf

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Hi, well done on what you have don so far.

For the ISC solenoid, pin 3M will go to an ignition switched +12V, pin 3Q will go to an Aux Output channel (from 1 to 8). The Ignition switched +12V could be the one used to power the ECU, or you can use one from somewhere else, possibly the supply for the ignition coils or injectors. Just make sure that the supply you use can handle the additional load. You don't want to use a supply out of the ECU for this.

Pin 1A is not needed by the Vi-PEC. Some ECUs use this for shutting down safely or saving data after the key is switched off. All the other pins will not be needed by you (thanks to your alternator swap). Pin 3K is not required, but if the signal goes from 0v to 5v you could consider connecting it to a spare AN Volt channel for interests sake.

Scott

 

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Scott thanks and all the team running for the users.

How will I know the following? 

Quote "Just make sure that the supply you use can handle the additional load."End quote 

Apart from testing is there any other way to go around?From your experience from where would you take the +12V?

 

Thanks for the Support! 

Lewis 

Edited by iliasfyntanidis

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Generally the supplies are able to provide a fair bit more current than is required by the system, so adding some additional load is ok. If the current draw is too much after adding the solenoid then the most likely thing to happen is that the fuse protecting the circuit will blow. I would expect the current draw of the solenoid to be quite low, you could measure the resistance of the winding and work it out if you want to. If you want to be certain that no problems will occur you could fit a relay that takes power from the battery positive (via an appropriately sized fuse) and then supplies the idle solenoid. You would have one pin of the relay's activation coil to ground, and the other pin connected to an ignition switched +12V.

Scott.

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Scott

Does it make sense to power multiple 12V devices from one single power source?

For exapmle you mentioned in the first post that i can feed the ISC solenoid with ''the Ignition switched +12V could be the one used to power the ECU''

 

Can i for example split the wire in half that goes to +14V to my Vipec in order to power other accesories as well?

 

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Yes, it's fine to share the 12v+ supply to different devices, so long as the wire (relay, and fuse also) can provide sufficient current. This is often how the OEM wiring is organised also.

The downsides of using 1 source for multiple devices:

  • If a short circuit happens in one device, the others devices will lose power also.
  • It is more difficult to control the devices separately from each other, you will normally have to control the ground to each device to do this.

Advantages of using 1 source for multiple devices include:

  • Less cables, so a more simple system.
  • Less cables, so reduction in weight and cost.

Scott.

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Hi, this is not required by our ECU for running the engine. The only reason you might connect it is if you have a spare An Volt channel and are interested in how the pressure changes under certain conditions (temperature?).

Scott

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Interesting Scott.

How will i do the calibration map for the the OEM fuel tank pressure?I mean it's not a gauge that i can go and buy with its calibration sheet.....

Amazing how many many pins are out of the way when a standalone ECU takes it's place.

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I'm not sure how the sensor mounts into the tank, is it through the skin of the tank somewhere? Or is it on the fuel pump assembly that hangs inside the tank?

I think the easiest way to do the calibration would be to use a T piece and connector another pressure sensor (MAP?) that you have a known calibration for. You would then compare the fuel tank pressure sensor voltage against the other pressure sensor reading and start to build a calibration. Ideally you want some way to manipulate the pressure in the tank, but it would be worth considering the safety implications of any chosen method.

Scott.

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1)The 3A is ground for the fuel injectors.

2)The 3B is the PCM ground  

3)The 3C the output device ground(what's this?)

All of them are factrory pins in my OEM harness.

 

Till now i have grounded all my extra sensors and some factory ones such 3 GM MAP Sensor,CLT Sensor,Fuel pressure sensor and IAT Sensor to my Vipec where GND OUT is as this is for sensors.All of them in the same GND OUT.

 

I don't know where to ground the 3A,3B and 3C pins in my Vipec.The original pin out of my harness is in top of the page.

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3A would have been the ground the ECU connects to the injectors when the injector drives are "on".  3C would be the ground the ECU connects to aux outputs.  

Assuming both of these are decent sized wires I would use these two as the main "power grounds"

Connect 3A to one of the i88 main grounds.  Connect 3C to the other i88 main ground.  Dont bother connecting 3B to anything.

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Have wired up everything. Coils do spark on test mode, injectors the same, fan kicks in etc etc. 

One problem though. When I put Auxiliary 5 on TEST ON which is my fuel pump I don't hear her priming. I have connected 3N from my engine harness to Auxiliary 5.The factory ECU pinout is on post No1. Another image on the bottom. 

Any ideas? The engine starts right away with the factory ECU. So no problem with fuel pump relay, fuel pump or main relay. 

MX5 1999 ECU Pin Out.jpg

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6 hours ago, iliasfyntanidis said:

When I put Auxiliary 5 on TEST ON which is my fuel pump I don't hear her priming.

Is the Aux 5 polarity set to low and the driver type set to lowside?

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Then it should work if your wiring is correct.  To test you can pull the 3N wire out of the plug and touch it on ground, if wiring is ok then the fuel pump should turn on.

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Have done that also. Even changed Auxiliary Outputs. 

Can it be the something like the problem that it is described on this topic. 

Can I send to tech support the wiring diagram of my Mazda just in case there is something that overlooked. For example the earlier MX5's had a switch on the AFM. Mine doesn't (later model 2000 has a MAF which is deleted )but maybe there is somewhere else located that I missed. 

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Haven't checked that but will do. Things are messed up a bit because I have build a harness adapter(very tidy) to connect the Vipec with the plugs of the OEM harness.

Possibly have done something there. I know that the fuel pump for safety reasons primes when engine is started i.e. airflow is being created not when key is in ON position.Maybe a treaty of the OEM harness does not meet up with the philosophy of my adapter harness. 

Hope there isn't any damage with the board of the ECU.Is there a dedicated circuit inside the board where I can take a quick look and is it easy to open the case easily apart? 

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So it should work then?  How about at the fuel pump relay, measure voltage between the LT GRN & WHT/BLU wires while using the Test function in the ecu.  You should see near 0V with the aux output set to off, and near 12V with the aux output set to "Test (on)".

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Adam i will disconnect the fuel pump relay and send 12Volts straight to the fuel pump today after work.I will also try what you suggest me.The funny thing is that the car starts with the factory ECU.BUT I don't hear the fuel pump priming with the stock ECU either.

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For continuity purposes the pin out of Euro models its slightly different from the US models. 

Cars equipped with immobilizer have the fuel pump in 3P on the ECU. Which is mine situation. 

Cars without immobilizer have the fuel pump in 3N.

That is the reason. Apart from that,cars equipped with immobilizer( like mine)  the fuel pump relay does not have the Light Green(without immobilizer they have the Light Green wire) wire but a Red/White color wire that goes to the 3P ECU.All the other colors match the fuel pump diagram. 
 

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