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FreeEMS on an AW11 4AGZE 
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DIP8 - Involved

Joined: Mon Oct 20, 2014 7:55 pm
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Hi,

I'm investigating what it would take to get freeems running on a 4AGZE.
The engine has a distributor with two toothed wheels in a 24-1 configuration, from what I have seen this is already supported.
I will need 2 VR conditioning circuits, but I am unsure at this stage the phase of the output, and wether i will need to invert the VR signal or if this is done is software?

The engine has an igniter and single coil setup, would it be best to output to the igniter or use a high current driver directly on the coil?

The injectors are Lo-z, and is it recommend to batch the injectors?

The car currently runs an AFM, would it be better to replace the AFM with a supported MAP and IAT sensor?

I am only interested in running the engine in a mostly stock configuration at this stage, so this is mostly about learning and hopefully giving back.

I have been working for the last year as an junior embedded developer, involved in data acquisition.
So I know the basics about signal conditioning and cross compiling with GCC.

Is there a recommended hardware platform at this stage? I saw the jaguar board, how ever it seems tailored towards a specific efi system.

Thanks for the help,
Ethan


Mon Oct 20, 2014 8:15 pm
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LQFP112 - Up with the play
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Quote:
I will need 2 VR conditioning circuits, but I am unsure at this stage the phase of the output, and wether i will need to invert the VR signal or if this is done is software?

As I understand it, you really need to get the phase right at the input of the VR conditioner for best results (a VR signal is asymmetric). An oscilloscope is the best tool to figure out the phasing.
Your 2 VR conditioner requirement suggests using a MAX9926 based conditioner board (which has 2 channels). There are several out there (jb-perf, brickboard, and within a month or 2 I'll have a few of my own design).

Quote:
The engine has an igniter and single coil setup, would it be best to output to the igniter or use a high current driver directly on the coil?

Maybe Dan has some ideas about the best strategy to control a 4AGE. My guess would be that keeping the igniter would keep things simpler. Using a high current driver
would give you more control.

Quote:
The injectors are Lo-z, and is it recommend to batch the injectors?

A perhaps useless bit of information: on 16v 4AGE's they are batch driven by design, the injector channels are tied together on the OEM ECU PCB.

Quote:
Is there a recommended hardware platform at this stage? I saw the jaguar board, how ever it seems tailored towards a specific efi system.

If you want to start this year, Jaguar is about the only available option. Ravage would suit us 4AGE afficionado's better, but the project has stalled for a while
now and no hardware has been created that I know of. Even if a Ravage board where to come out soon, Jaguar would have the advantage of many hardware iterations beneath it's belt.

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Wed Oct 22, 2014 7:59 am
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DIP8 - Involved

Joined: Mon Oct 20, 2014 7:55 pm
Posts: 17
Hi, thanks for the info!

Image

In the diagram, I am guessing NE and G1 are the connections to the single tooth VR, and G- and G2 are the connection to the 24 tooth VR?

The igniter has IGT and IGF, from what I can see reading the manual it looks like IGF is a feedback output, can this be ignored?
So then I drive the igniter using IGT, which looks like it is connected internally to an IGBT or similar power transistor?

So I will use a MAX9926 for the VR inputs,
4 x LM1949 for the injectors,
a circuit to drive the igniter transistor,
a 5v logic and 5v analog supply,
relay driver for fuel pump and supercharger, possibly also for engine bay fan and radiator fans?

what else will I need?

Cheers


Wed Oct 22, 2014 9:44 am
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QFP80 - Contributor

Joined: Mon Dec 02, 2013 5:57 pm
Posts: 57
I have a toyota 7mgte with a very similar CPS setup. In mine, G- is the ground, NE is the 24 tooth, and G1/G2 are individual 180* opposing pickups for the 1 tooth wheel. I just picked one and used it as the sync. Using the Max9926 is strongly recommended over the LM chip for that -- I couldn't get the LM to keep sync at all. My ignitor was probably not like yours at all, but it ran off 12 V logic. IGF was feedback for the stock ECU to know that a spark didn't fire so it could avoid fueling the engine if something was wrong -- I ignored it completely. I drove IGT (in addition to two other signals I had for multiplexed 3 channel ignition), but ran into some issues at high RPMs with it. It worked well as long as I kept the dwell <2.5 ms, but would start getting too smart for its own good above that. I strongly recommend making your own ignitor with IGBTs.


Thu Oct 23, 2014 6:46 pm
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DIP8 - Involved

Joined: Mon Oct 20, 2014 7:55 pm
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Yeah, I found a guide to rebuild the distributor and could see from the pictures there are two pick ups form the single tooth wheel. Are there any proven circuits around for directly driving the coil? I found a chip VB525SP-E, but not sure if its any good or not.
Cheers for the info.


Fri Oct 24, 2014 5:39 am
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Hi and sorry I took so long to say hi.

VAF/AFM sucks. You don't have to remove it, but you won't be using it either. The hardware you get will probably include a MAP sensor. If not, there are many OEM ones you can use.

Batch is never recommend but at the same time, it can work just fine if well setup. My car runs TBI batch style, and runs nicely despite the ultra old tech and crappy tune.

Direct driving coils is a huge fail. Don't do that. Use an ignitor even of not the Toyota one. Having said that, your diagram makes it look like the ignitor and coil are one part. Photos are nice to see.

Fred.

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Fri Oct 24, 2014 10:07 am
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DIP8 - Involved

Joined: Mon Oct 20, 2014 7:55 pm
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Hi Fred,

Yeah with you on the AFM thing, Does the jaguar board (with 250Kpa Map) and one of JBs Injector boards sound like a good combination?

You say batch is never recommended, so sequential is is better hardware, software and performance wise? What would be easiest to get running?

The ignitor is bolted to the coil, on the same bracket used to attach the coil to the chassis. I grab a photo in a bit.

Thanks


Sat Oct 25, 2014 1:38 am
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DIP8 - Involved

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Is there a quick and easy ignition system I grab off a car at pick a part?


Sat Oct 25, 2014 1:42 am
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Sorry for the lag authorising those posts. No more will need that, you've exceeded the threshold. Typically I bypass that if the person looks legit and not a time waster, but I've been busy.

Just noticed you're a kiwi! Where abouts are you in NZ? I love AW11 MR2s and nearly bought one a few months back.

For a four cylinder with current code, I would run it sequential + wasted spark or COP + semi-sequential timed batches of 2. Either will run very well and both have advantages over the other. Distributors are annoying, so I'd likely wire up the injectors for sequential (you can run them semi this way if you choose) and find a wasted spark coil, ignitor, and leads.

Jag w/ 250kPa + new model JB low z board = win.

Fred.

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DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Sun Oct 26, 2014 8:37 am
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DIP8 - Involved

Joined: Mon Oct 20, 2014 7:55 pm
Posts: 17
Hey Fred,

Yeah I'm in Auckland, I saw some stuff about freeEMS on oldschool.co.nz a few years back, but only now am I financially and intellectually ready to play around with it.
The AW11 is a fun car, but its a struggle to get through WOFs for some reason, mostly because of tinworm.

The later 4AG(Z)E run a map sensor and coil packs, so should be able to pick up something that will work. I am picking that the easiest way to use the supercharger is just to have it on a manually activated switch, and then play around with activating it with throttle position or engine load later?

Thanks,


Sun Oct 26, 2014 10:32 am
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