Link tuning - Anyone help a newbie?

Mad Kiwi · Post by **Mad Kiwi** » Sun Jan 29, 2012 7:52 pm

HI Guys

Have a NZ new 89 NA with a turbo and (i believe) 360cc injectors with a 2 1/4 Ex system running a pc tunable link G1 (CPU is dated 2009).

The car runs very well but seems excessively rich at idle and hunts between 650 to 950 rpm (sometimes worse) at idle and sometimes stalls when approaching lights etc.....the car running in the garage for even 1 minute makes breathing difficult and your eyes STING....even with all the doors open. I know it's not scientific but none of our other cars do this (including a non turbo 1990 mx5).

Anyway a few questions if you don't mind...

- looking at the software, how does the data log get a 20 - 100 TPS reading when I understood there is no TPS fitted to these cars...? other than open and close.

- I want to make sense of the fuel table numbers but without a wideband can I? ...i.e are they just a reference to work with or do they actually relate to a specific stoich value (or whatever...)

o If the numbers are just a plain numeric reference, should I get a wideband AND does the Innovate MXL unit (readily available here) connect to my Link G1 okay?

- when reading / saving to the link is the "STORE" command to save to the link or does that save the link map/file to the pc...? (I don't want to overwrite the map I have before I save a reference copy first...)

Thank you.

WideOpenThrottle · Post by **WideOpenThrottle** » Sun Jan 29, 2012 9:12 pm

The throttle sensor is the black box on the right side of the throttle body.

Your rough idling more than likely untuned larger injectors but also could be a dirty throttle valve [quite common], or both.

You may also have a vaccum leak on the intake track.

If? you have an air flow meter it may be sticky.

Could have a faulty Idle speed valve.

Sounds like the Link needs a good tune but can't help you there!

SLYDIT · Post by **SLYDIT** » Sun Jan 29, 2012 10:35 pm

funny idle can also be the injector timing..the exact point at which the fuel is injected into the port. if it isnt injected at the right time the mixtures will be off.
think of it as ignition advance but for injectors

if you r car doesnt have a variable TPS then you can bolt on one from an E30 BMW

SLYDIT · Post by **SLYDIT** » Sun Jan 29, 2012 10:38 pm

can you post a screen shot of your fuel tables?(in Milliseconds)
i have the 360cc injectors in my turbo system and may be able to cross reference the injector times.

Post by **jif** » Mon Jan 30, 2012 9:45 am

The car runs very well but seems excessively rich at idle and hunts between 650 to 950 rpm (sometimes worse) at idle and sometimes stalls when approaching lights etc.....the car running in the garage for even 1 minute makes breathing difficult and your eyes STING....even with all the doors open. I know it's not scientific but none of our other cars do this (including a non turbo 1990 mx5).

Anyway a few questions if you don't mind...

- looking at the software, how does the data log get a 20 - 100 TPS reading when I understood there is no TPS fitted to these cars...? other than open and close.
For the early NA's there's no continuous TPS value, altho you can fit an automatic TPS to get it.

- I want to make sense of the fuel table numbers but without a wideband can I? ...i.e are they just a reference to work with or do they actually relate to a specific stoich value (or whatever...)

they don't relate to stoich, they relate to the base fuel infjector sizing value

o If the numbers are just a plain numeric reference, should I get a wideband AND does the Innovate MXL unit (readily available here) connect to my Link G1 okay?

I think you'd need the FlyinMiata Link to use a wideband.

- when reading / saving to the link is the "STORE" command to save to the link or does that save the link map/file to the pc...? (I don't want to overwrite the map I have before I save a reference copy first...)

that is to STORE to the Link's internal memory

Suggest downloading the FlyinMiata link tuning manual and have a really good read of it. Even if you dont have the FMLink chip, it will mostly apply to your hardware. Also the miatapower mailing list archives have a ton of info in them, including from the FMLink's author.

For idle, it sounds like you need to take some fuel away from the idle zone, at least until its closer to stoich. Mine managed to idle at about 15:1 with the bigger rx7 550cc injectors... tho with big injectors (esp ones with fewer holes) they dont work too well at low flow rates.

A wideband oxy sensor would be a good investment - even if it's not hooked into the Link's autotune you can get a feel for how the fuelling curves need to be adjusted. And they're dirt cheap now!

HTH.

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sprsta · Post by **sprsta** » Mon Jan 30, 2012 10:42 am

so your G1 is a wire in V5?

if it sounds like a rotary and is hunting at idle you will be masively overfueling.
check what zone(s) you are are in at idle then go to your zonef editor and and start removing fuel one point at a time till it will not overfuel just check that it stays in that zone while you are making changes

- looking at the software, how does the data log get a 20 - 100 TPS reading when I understood there is no TPS fitted to these cars...? other than open and close.

you should have a 0 - 100 but no range in between it just works like an on off switch you may need to re setup your tps

o If the numbers are just a plain numeric reference, should I get a wideband AND does the Innovate MXL unit (readily available here) connect to my Link G1 okay?

yes it can connect to your link but your link only has a NB input.
The MTX unit has two outputs one is a 0-5v wb output and 0-1v nb simulation output, this is the one that will be connected to the ecu

stalls when approaching lights

to address this you will need to adjust your clamp setting raise it by a point or two at a time so that when you come out of overrun your idle hovers around 1000rpm for a second before falling to idle

2low2c · Post by **2low2c** » Mon Jan 30, 2012 7:35 pm

first of all how long has it been doing this for ?
it might not be in the link at all .
if it has been doing this all along i would be looking at the cold start settings and idle settings .
if it is something that has just started to happen then it could be leads, plugs, timeing etc.

r3spct · Post by **r3spct** » Mon Jan 30, 2012 8:20 pm

I can do a tune on this for you if you want, road tuning with a wideband sensor, $250

Im in WestHarbour

Mad Kiwi · Post by **Mad Kiwi** » Tue Feb 07, 2012 3:42 pm

Thanks for all the advice guys. I will follow some of the suggestions here before I take it somewhere.

Part of the idea of buying the car is to learn this stuff.
Unfortunately work has been incredibly time consuming lately and i haven't had a chance to look any further.

To answer a couple of questions, yes it has always done it.

Slydit, I will post a screen shot as soon as I can, would really appreciate some input from you especially as you have the same injectors ( from what I was told when we bought the car).

Cheers.

SLYDIT · Post by **SLYDIT** » Tue Feb 07, 2012 4:59 pm

if your injectors have a black body (or even cherry red) they'll probably be the "365cc" injectors. these injectors actually flow more like 385cc under normal use. i think the test pressure was low when they flowed them.

SLYDIT · Post by **SLYDIT** » Tue Feb 07, 2012 7:44 pm

I just had a hunt around for my 6 year old data logs when i set the car up...
after much searching i found about half of them.

i can tell you that my cold start injector times were about 3.5-4ms and i found one hot idle log that had idle fuel at about 2.0-2.5ms. not sure how accurate these are as they were probably done before the final tune, but it should give you some idea of idle fuel settings..