Mr.E.G.

The dilemma

I have a 30-1710 AEM Plug and Play that I am installing in my boosted 90 Miata. I hope to accomplish two things with this thread:

• Get many questions answered.
• Create a thread that is useful for anyone else who attempts the same. It would be great if this could evolve into a build thread or perhaps an "AEM Standalone Install for Dummies" thread (only I'm currently the dummy).

My plan

In the interest of keeping everything organized, I plan to list (in the second post of this thread) all of my questions in an ordered list. Once a question is answered (or if I figure it out on my own), I'll strike it through and reference the post where the answer occurred. That way, anyone can land on the first page of this thread and see which problems have been addressed and which are outstanding. I figure that if I am going to beg for help, I should at least make it easy to navigate.



Hardware, etc.

Here are the details about my car and the setup:

• 1990 Miata
• 1.6 liter with stock internals
• Flyin' Miata turbo kit with GT3071r turbo, intercooler, etc.
• 440cc injectors
• I will be running E85
• Coilpacks from a 1.8 (the previous owner did this and I don't entirely know why)
• AEM Plug and Play standalone 30-1710
• AEM jumper harness (the harness that simply extends the factory ECU wiring harness... I intend to use this for all wiring changes rather than hack up the stock harness)
• NGK Powerdex wideband O2 sensor and "brainbox"
• Motec 3 bar map sensor
• Boost solenoid
• Intake air temperature sensor
• A rather questionable aftermarket fuel pressure regulator
• Various supporting mods (clutch, torsen diff, big radiator, etc.)

The Goal

I would like to make at least 220 whp but obviously I'd prefer more. I will have the car tuned by Tony Palo here in Texas (simply put, he's a big deal in the tuning world) and I have the utmost confidence in his tuning abilities. I will be running E85. I intend to use the O2 sensor to actively trim while I drive and not just as a readout to let me know when something goes wrong. I've known people who had cars that were great at WOT but they sucked at partial throttle. I want my car to have good transient response.

I would like to build the fuel injection system with scaleability in mind. I don't want to do anything shortsighted and (if it doesn't screw up my time frame) I would not at all be opposed to adding coil-on-plug ignition or a higher resolution crank trigger wheel. In the future, when I want even more power, I would like to more or less be able to add a built engine to the mix, up the boost, and get some additional tuning. In other words, I'd like to build a high-horsepower-capable fuel injection system and I would like a great degree of control over the engine.



Thanks

I really appreciate any help you guys are willing to give.

Mr.E.G.

Questions:



ECU and general wiring

• How do I refer to my AEM ECU? I hear people refer to version 2 and whatnot. Is mine a "first gen" or something?
• I am using the jumper harness that AEM sells AEM ECU Patch/Extension Harness 30-2983C. How would you connect to the AEM ECU otherwise? My ecu did not come with any wiring pigtails or anything to that effect, so aside from my factory engine harness plugs that occupy two of the ECU's ports, how do people normally connect to the other two ports on the ECU?
• Where do you guys get automotive wire and connectors? I don't want to resort to using speaker wire here

Fuel system

• Will my 440 cc injectors be sufficient to make mid 200s power on e85 or should I just take this opportunity to upgrade injectors? I will need big injectors eventually, so maybe I should just address this now.
• In the interest of scaleability, should I go ahead and get a fuel pump as well?
• How about an adjustable fuel pressure regulator or new fuel rail?

Sensors

• What is the cleanest way to run power to my O2 sensor? The sensor uses prefabbed harnesses for most connections except for, of course, the power and ground. I was thinking of running a dedicated and fused power cable from my battery to the engine bay and then terminating it at a bus or junction box of some sort that is attached to, say, the firewall. That way, any devices under the hood that need to connect to power can just tap into that. How does that sound?
• Does the ground for the O2 sensor need to connect to any specific ground point on the Miata? I assume just grounding it somewhere on the chassis would be fine since its ground is for powering up the system as opposed to some fancy pants signal ground... I think.
• What the heck is this metal plate thing that came with my boost solenoid?
  As you can see, it came with some hardware too and I can't figure out how that is supposed to work. I mean, I can certainly rig up a mount, I just don't know how that would fit into the mix.

Ignition
So my ignition setup is kind of weird. The previous owner removed the external ignitor and wired in NB coils. No one can seem to fathom why this happened or what they were hoping to solve. I found an ancient thread on miata.net where someone discussed such a mod and it was not very detailed. I would like to be able to make some modifications to my ignition system but I really need to figure out exactly which wires were modified first. I'll take some pics and ask some questions about that in the future as I investigate further.

However...

• If one was not concerned about being budget-conscious and bearing in mind that the AEM ECU has the ability to drive a variety of custom-wired ignition solutions, is there an ideal setup that someone could recommend? For instance, some sort of coil-on-plug solution that is wired into the spare ports on the ECU as opposed to a plug-and-play solution. Is this all just a waste of resources, meaning, that I should just keep the factory wiring (as in, return my ignition wiring to a factory arrangement) and install a COP setup like the one sold by Trackspeed:Trackspeed Engineering ?

Thanks, guys.

Mr.E.G.

I did some checking an apparently I have a "Series 1" EMS.



Also, I have a tentative answer regarding the ignition issue. According to AEM's tech support, I can use four of their smart coils. The smart coils need a power and ground and I then wire the signal wire from the ECU which tells them when to fire. I would repurpose the factory 1 and 2 coil drivers to the smart coil for cylinder's 1 and 2, and I
would use pins 3A and 3B (from the AEM ECU's spare ports) for cylinders 3 and 4 respectively. I must then simply run spark plug wires to each cylinder. Obviously, this would require coming up with some sort of bracket for all of this and it may also require that I run a separate signal wire for the tach.

I think that sounds like an easy solution, and I may have to go that route if I can't make sense of how my factory harness has been altered, but it may not be as clean as reverting back to stock wiring and then installing a ready-made coil-on-plug setup.

Mr.E.G.

Also, obligatory cat contribution:

Mr.E.G.

I figured out how the mounting plate works on the boost solenoid. Pretty obvious now, I suppose:

Savington

iTrader: (31)

Pretty sure I talked to you on the phone this morning. Hopefully I answered all your questions.

Mr.E.G.

Indeed you did, sir. Thanks again for your help.

mrmiatanut

Is your car up and running on the AEM now?

Mr.E.G.

Not quite. I just can't find time to finish getting it up and running so I'm letting it go.