Scooby-Mike

Hi,Just brought an AFR gauge for my MY97 scoob 2000 turbo 5dr.
Where do i tap into to link the AFR up?? and which wire?
Is it directly on the sensor or the ecu?
any help appreciated as I'm itching to get it fitted.

P.S is it the same for a MY96?? mates just brought one too!

Thanks,
Mike.

Dark Blue Mark

MY97 is different to MY96 ECU.

You need to wire direct to the ECU itself. When you look at the ECU, take the bottom plug out - this is plug 136. You need to find pin no. 5 for the AFR wire.

I would wire the live and earth to the ECU as well.

Earth is 13
Live is pin 11

Cant tell you what colour they are though

As a reference point, look to the top corner of the 136 plug 1 and 2 will be together, then a little gap, then the next pin is 3 and so on. Last one on the top row is 11 and should be slightly on its own.

Let me know if you need a diagram sending.

MB

Scooby-Mike

Anyone know the colour of the wires to tap into??
and also what readings should I get at idle?, medium acceleration?, and full??

vulnax999

iTrader: (7)

Depends on the gauge mate, Lambda link, or Autometer gauge, or other?

Rich on load/throttle, back and forward on stoich / cruise, all over place on idle, off scale lean on total throttle lift off ( for emissions! )

If that helps!

Scooby-Mike

Hi, its an auto gauge type. round same as the splitfire job.
Is it normal to run rich on full boost?? what should I be looking out for??

Dark Blue Mark

Should be to the I of Rich on the gauge if its the autometer one. If you do a search you will find the optimum voltage when Rich.

The sensor is heated so will take a few mins before it registers on the AFR. At idle it will slowly bounce from lean to rich, and on cruise it will do this a bit quicker.

Its really only of use on boost, as it shows what your mixture is at open loop. When its bouncing its on closed loop. It will show if you have a dead maf or lambda though, which is why I like being able to see the closed loop info.

MB

Scooby-Mike

How will I know if I have a dead MAF or lambda from the gauge??

Dark Blue Mark

Depends really, but a dead lambda sometimes shows no reading at all, or it just stays fixed. Dead MAF's ive seen just give random lights. There's better ways of determining a failure, but the AFR will tend to show if one of them is duff.

MB

Scooby-Mike

so, should it be in the rich section on full boost? I have 6 led's in the rich section on the gauge, where should it be and when should I start to worry

Dark Blue Mark

Do a search, but to help, it should be 0.85 and 0.9 volts. Any less than 0.85 and you are lean.

You need to find the range of your gauge, then divide that by the number of lights on there, and multiply it by the number of lights that are on. You need a wideband lambda to check it accurately, but the one you have will give you a rough idea...

MB

Dark Blue Mark

And yes, it should be rich on boost.

MB

gregorak

You can find all the informations you need on the apexi web site.
There is the manuals of all the Japaneses ECU's including all years for scoobys.
Check this link
http://www.apexi-usa.com/productdocu...savcr_wire.pdf

gregorak

ooppss sorry the link with the good wiring diagram including AFR is this one ;
http://www.apexi-usa.com/productdocu..._safc_wire.pdf

Dark Blue Mark

Think he's got it wired fine by the looks of it mate, good link though.

MB

Scooby-Mike

Ok, got it all wired up and working.

At idle it goes from the first 2 leds in rich and then drops right off the scale and keeps doing this.

On over run its off the scale

On full boost its on the second of 6 led's in the rich

Is this normal, should it be richer at full boost? the car is a standard my97.

thanks for the help so far,
Mike.

Dark Blue Mark

Should be on the "i" of the word rich on the gauge at full boost

The gauge is 0-1v scale I believe and has 20 lights, therefore 1 light = 0.05 v (roughly, as these aren't truly accurate) You are seeing 16 lights = 0.8v

You need 0.85 to 0.9 on boost ideally, but as I say, gauges aren't completely accurate.

John / Bob care to comment?

MB

vulnax999

iTrader: (7)

Sounds about right, Mike, 2nd green / 3rd green rich is usual, so your ok.

Rich fuelling is for cooling and avoiding lean mixtures at boost etc, maybe help prevent a little knock, even though stoich is theoretically best in an ideal engine!

How sooty is your exhaust, if a decat system?

Neil

Dark Blue Mark

Its standard from comments above, Neil.

The Autometer AFR's ive had have all showed similar readings and been ok'd on rolling roads so it should be fine. Trouble is, any slight earthing issue etc, it might nock 1 light off the gauge, so not entirely accurate, just a good guide.

MB

Dark Blue Mark

PS, you owe me a beer for all this help

MB

Scooby-Mike

Sure do mate . checked instructions with the gauge and I am getting about 0.85v, so seems ok.
So now I know I'm getting enough fuel, what causes knock?? is it lack of fuel? and how can I prevent it when I turn up the boost a little.

Dark Blue Mark

Have a search, there are some very good descriptions of it.

Very high ambient temps can cause it, too much boost etc.

You REALLY need a Knock link, the AFR is only a guide. There are numbers of people who have fitted KL's and they've saved an engine from it!

MB

JohnnyR6

My autometer guage lights up the last rich on anything other than idle, at idle it lights up all the rich lights (they all sort of flicker) the only time the stoich lights up is when the ignition is on without the engine running, have i wired it up wrong? It s on a my95 sti 2. Oh sorry for barging into your thread.

Cheers Johnny

Dark Blue Mark

Quite possibly wired up wrong, or your 02 sensor is buggered.

What pin did you use for the signal? The ECU is different to the one in this post.

MB

JohnnyR6

i will have a look as i cant remember, someone on here emailed the info to me (cant remember who), i will get it checked out also forgot to mention i have a knocklink and the car on the rollers a while ago and all seems to be fine

Scooby-Mike

O.K, I'm going to turn up the boost to about 14psi, Only thing i've noticed is that in 5th gear I get alot of spiking. It goes to 16psi for a brief moment on acceleration. with fc being at 17psi will i stilll be able to increase the boost?

could it be that i have taken the boost gauge off the manifold spare outlet?

Dark Blue Mark

When you say spiking, you mean boost spike or det on the knocklink? 14 psi should be fine, the boost cut takes a few secs to kick in from memory, so short spikes should be ok.

Cant remember if you have one, but upping the boost without a KL inst a good idea IHMO.

MB

Scooby-Mike

yes, boost spike. I don't have a knock link but don't plan on any serious increase for a while.

Dark Blue Mark

Will probably be ok, its normal to have a "peak" boost figure a couple of PSI higher than the "held" boost.

Still get a KL! Unlikely, but if you had a det issue and you up the boost, you could be making matter worse.

MB

Scooby-Mike

what sort of money should I expect to pay for the KL??

Dark Blue Mark

£150 new from BRDevelopments. Or put up a wanted ad.

MB