yoeddynz

DIY Fuel injection thread.

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Currently tuning my megasquirt 2 and I think it's sweet so far. I've had a few headaches along the way (assembled it, wired it etc all myself) but I think it has definitely been worth it for the things I've learnt. Wiring it in is relatively easy but setting your engine up in the software takes a fair amount of reading depending on your ignition setup as anything out of the ordinary can be tricky. Fuel setup is simple.

The newer tuner studio is a lot better than the old mega tune software (apparently) I find it pretty easy to use. In saying that I've never played with any other ECUs

Stay away from the relay boards for the MS. I'm running one and the connections are pretty shit and there's not really enough connections on it for most setups. I've made mine work but next time I'll do it some other way for sure.

I'm definitely using one on my other projects, and I think after you've done it once it becomes so much easier as everything starts to make sence

I've got a e-manage ultimate (piggy back) for my 2jz and it looks ridiculously easy compared haha. A few wires later, select engine in the options and you're good to go.

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They have an autotune option as said earlier, you have your main fuel table that you set yourself then you can have an AFR "target" table which autotune will use to fine tune your main fuel table, easy as. Just keep an eye on the AFRs manually so you don't run it lean or anything silly.

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Cool. As always more good info from all. Cheers.

Another tick for link is that Prozac works next door at nzefi and that's always handy.

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Another question..

What's the deal with resistance on injectors? It seems that some ecus will only run up to a certain resistance?

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most will only run saturated, (high resistance) not many run peak and hold (low resistance) you can run low resistance injectors saturated though. just need to put a resistor in series with the injector.

think from memory link says anything below 6ohm will need ballast resistors. anything above you can run directly. the resistor is just there to stop the injectors pulling too much current,

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Yep ya got high impedance injectors, usually around 10 ohms, and low which tend to hang around 2-4 ohms.

Low impedance can have an advantage by reducing the dead time when they open by mashing in full 12V and then cutting it back after a few milliseconds, but you need a proper peak-hold driver to do it. If you're gonna mash ballast resistors in you're better off running high imp injectors.

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I'm presuming the injectors that come on these engines will be high resistance items then? Any way to tell. Can I just put a meter across them?

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Yep just check with a multimeter.

A lot of injectors are around the same size so are pretty easy to interchange between engines. The plugs are often all that needs adapting.

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alot of cars around that era run a resistor pack, (witch usually can be reused on aftermarket ecu) if they are running low imp injectors anyway. no real drama to run resistors other than wiring them in.

but they are likely to be high anyway

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Yah the 5MGEs I deal with run low z with resistor packs, but I'm replacing them with high z 13B jobbies. 550cc compared to 180cc.

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rx7 550's are yuck. i'd run caldina gtt 540's(high resistance) or some 510/560 evo injectors + ballast

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pretty hard to find a decent matching set. mate had 8 of them tested couldn't get a matching set of 4, out of all of them. bad spray pattens and flow rates. plus they are spose to have a pretty narrow jet style spray pattern, to suit the rotary inlet manifold.

another car i tuned was running them. dude just threw a set in. i suspect it had the same issue. average afr was good on wideband, but under hard acceleration it would blow a bit of black smoke. like it had rich and lean cylinders. would also idle a bit junk and seemed to run into knock earlier than similar setups.

i'd at least get them tested if you use them. some people seem to have had decent results with them.

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Ah ok. Yeah I have 2 sets of 6, both of which have apparently been tested / cleaned / checked out or whatever before I bought them so in theory they should be good.

I'll probably get them done again anyway just to save any headaches when I try to tune the bastard

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Can i just put some questions slash thoughts in here?

I am looking at running a link plus that I am getting of Uterus, and am going to be running throttle bodys.

the link is setup for a 1uz from factory

I'm running a 2jz NA

Does anyone know if I am going to have to send away the link to get the triggers changed?

2jz runs a sigle dissy clearly, where as the 1uz has two....

Plus, i assume the link plus also supports auto tune? and what sort of issues am I expecting to have with running throttle bodys? i assume idle is going to be my biggest problem?

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Lack of vacuum makes it hard to tune with a map sensor like most normal setups (speed density), so you will probably need to use alpha-n which is tps/rpm based code.

Not sure on the answer about the link.

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Question 6,

Underneath my throttle body is a big ugly pwr valve for idle control. By going to link or MS etc can I get rid of this and fitnin place a smaller unit that will do the same job? Or is there some neater way of doing things to control the idle speed. I figure it's main job is for cold starts ?

Otherwise is this stock unit easily controlled by aftermarket ecus?

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Most people just crack the throttle/s slightly to idle up a little, but in this build where efficiency and reliability is key you probably want to retain that, or a similar version of it.

You can get a stand alone ICV/stepper motor that just has a pipe in and out rather than the type that sit on the intake manifold/plenum/throttle body. These are much easier to mount on an after market intake. You can control them from a PWM out put on the ecu.

Again, just stay with you factory ecu :P

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Link has very good idle speed control characteristics. I run a 2 wire solenoid and find it infinitely better than stepper motors. So much easier to set up and wire.

As for Als question, if its a plug-in ECU - you might need to get a new chip slammed in it to suit the JZ instead of the UZ. If its a wire-in, everything should be configurable using the PC link software.

My last engine was tuned to alpha-n and i found it to be very nice to drive. Possibly even better than my current MAP based setup at low throttle openings.

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seedy, is it an old g1 linkplus? could be wrong but, think they run a 1uz specific sub board. pretty sure you will need the standard 24tooth + sync sub board for the jz, same setup as 4age etc.. and yeh as above just run it in tps mode for itb's. they have a real shit version of autotune thats not worth using if its a g1 link. idle will be fine, you can use the dashpot stopper thing on 20v throttles (if thats what your using) with some fancy plumbing to crack the throttles for cold start

/im too slow

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