iliasfyntanidis Posted September 4, 2016 Report Share Posted September 4, 2016 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 thesolenoid. A spring is used to automatically close the solenoid. Connect one terminal to theengine 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 monitor4)1O General field coil control5)1Q Generator warning light6)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 Quote Link to comment Share on other sites More sharing options...
Scott Posted September 5, 2016 Report Share Posted September 5, 2016 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 iliasfyntanidis 1 Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted September 5, 2016 Author Report Share Posted September 5, 2016 (edited) 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 September 5, 2016 by iliasfyntanidis Quote Link to comment Share on other sites More sharing options...
Scott Posted September 5, 2016 Report Share Posted September 5, 2016 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. iliasfyntanidis 1 Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted September 10, 2016 Author Report Share Posted September 10, 2016 ScottDoes 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? Quote Link to comment Share on other sites More sharing options...
Scott Posted September 12, 2016 Report Share Posted September 12, 2016 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. iliasfyntanidis 1 Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 9, 2016 Author Report Share Posted October 9, 2016 Scott the Fuel Tank Pressure pin 2A in my ECU is it something that has to be connected somewhere in the i88? Quote Link to comment Share on other sites More sharing options...
Scott Posted October 10, 2016 Report Share Posted October 10, 2016 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 Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 10, 2016 Author Report Share Posted October 10, 2016 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. Quote Link to comment Share on other sites More sharing options...
Scott Posted October 10, 2016 Report Share Posted October 10, 2016 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. Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted September 23, 2018 Author Report Share Posted September 23, 2018 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. Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 24, 2018 Report Share Posted September 24, 2018 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. iliasfyntanidis 1 Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted September 24, 2018 Author Report Share Posted September 24, 2018 You are golden. Thanks again for your time and support. Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 25, 2018 Author Report Share Posted October 25, 2018 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. Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 26, 2018 Report Share Posted October 26, 2018 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? Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 26, 2018 Author Report Share Posted October 26, 2018 Yes. Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 26, 2018 Report Share Posted October 26, 2018 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. Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 26, 2018 Author Report Share Posted October 26, 2018 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. Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 26, 2018 Report Share Posted October 26, 2018 I already have a wiring diagram for this model. Have you checked there is 12V on the white/blu wire (comes from the main relay) at the fuel pump relay? Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 26, 2018 Author Report Share Posted October 26, 2018 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? Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 27, 2018 Author Report Share Posted October 27, 2018 Well I measured 12.3 Volts before the fuel pump relay but after the main engine relay on the White/Blue wire that's on the left. The one in the green circle. Quote Link to comment Share on other sites More sharing options...
Adamw Posted October 28, 2018 Report Share Posted October 28, 2018 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)". Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 28, 2018 Author Report Share Posted October 28, 2018 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. Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted October 29, 2018 Author Report Share Posted October 29, 2018 FIXED Thanks for all the support. After 3 years on jack stands and a major rebuild with top notch parts the car is ready to hit the road and track. Quote Link to comment Share on other sites More sharing options...
iliasfyntanidis Posted November 5, 2018 Author Report Share Posted November 5, 2018 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. Quote Link to comment Share on other sites More sharing options...
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