MAF setting Questions

Ã–se480T · Post by **Ã–se480T** » Fri Mar 02, 2007 2:03 pm

Hi there,

i'm little confused about the right MAF setting.

Have set it to 382Ohms like stated in the rep. handbook and then been screwing it up till the voltage on the lambda-proof-lamp-connector was cycling between 0,9 and 13,5V...

Now the resistance is at ~800Ohms... I think that's very high. And most of you set it to certain numbers around 400-500 and not checking the lambda...

Is there some kind of missunderstanding? Or is it OK that way?

Can anyone help me on this topic???

Yours,
Oli....

crispy-d · Post by **crispy-d** » Fri Mar 02, 2007 2:46 pm

Ummm, not sure what you mean by lambda-proof-lamp-connector, but the voltage read at the lambda should be between 0-1V, and when mine's idling it's 0.56V
0V is rich and 1V is lean.
The MAF is said to be set to 382ohms, but mine was at 446ohms when I tested it, and most others seem to report their's being higher than 382ohms too. I had mine set to 650ohms for a bit, but it's drinking too much fuel at the moment for some unkown reason, so I've put it back down to 446ohms. I'm pretty sure it's not supposed to be up at 800ohms tho.

Crispin

Ã–se480T · Post by **Ã–se480T** » Fri Mar 02, 2007 4:39 pm

There is a connector on the cable to the MAF-sensor, where one could connect a LED-Diode to check the CO... It should blink if the MAF is set correctly... Should be a black-blue-cable...

OK, so if it's 0,9v all the time, it should be too lean, and when set correctly, should be between 0 and 0,9 volts... So I think it's correct... Because it's going down to 0V, then 13,5V and then 0,9V again... But still little confusing??

Or does anyone have some more comments on this??

Edit: In other words: Where do you measure the lambda???

crispy-d · Post by **crispy-d** » Fri Mar 02, 2007 5:55 pm

Oh right, didn't know about the CO LED testing thing. If you follow the lambda sensor wire up from the sensor into the engine bay, you'll see it splits into two connectors somewhere near the battery. The double connector powers the heating element, and the single one carries the voltage signal to the ECU. If you test the voltage there, it should read between 0-1V. I didn't realise you were testing the lambda voltage at the MAF (if that's what you are doing) - didn't realise you could do that.
What's more, my lambda reading doesn't fluctuate, it sits steadily at 0.56V. It should only change when you operate the throttle.

Perhaps someone who knows a little more will put an end to the confusion!

Ã–se480T · Post by **Ã–se480T** » Fri Mar 02, 2007 6:33 pm

OK thanks, I think I know what cable it is that's connecting to the lambda-sensor directly... It's two white cables and one brown or something that's connected to a green one in my car... Could it be?

The cable or connector for the proof lamp is located besides the MAF-Cable... Do you know the rep.-handbook??

crispy-d · Post by **crispy-d** » Fri Mar 02, 2007 7:01 pm

That sounds like the right wire, yes. I don't know the rep.-handbook is. I do have a Haynes Manual, but that's about 230 miles from me right now, as I've escaped Bristol for a while and have come home for some home-cooked food

I found the little testing wire you're talking about - but have not managed to find anything to connect it to. I'll see if it works when I can find an LED!

No matter what, if it's not below 382ohms then there shouldn't be any risk of the engine running lean unless there is a fault of some kind. If you are running a 'Rich Mod' then you can set it to up 650ohms to get the most out of it.

Ã–se480T · Post by **Ã–se480T** » Fri Mar 02, 2007 7:23 pm

hehe, alright, i didn't have a led as well

That's why I connected my meter instead.. In my rep.-handbook it says to connect one wire from the led to the connector, the other side to the plus of the batterie... and it should blink... so I thought changing between 0,9 (i think led is off) and 13,5v (led on) would be ok... but I will measure directly at the lambda-wire tomorrow...

Unfortunately I don't have a rich mod... read about it here the first time.. seems to have something to do with the injection-ports?

crispy-d · Post by **crispy-d** » Fri Mar 02, 2007 7:38 pm

Ooooooooooooh I seeeeeeeeee!! Yes, if it's that tester that you're connecting the meter to, then yes it will be correct to see those results.
That clears the fluctuating readings then! It's meant to be a blinking LED, literally

The Rich Mod is indeed worth having, but you'll have to wait until rpruen has a little time to spare to modify your boost/ignition ECU, as I hear he's somewhat busy at the moment. The Rich Mod 'simply' raises the boost to around 13.5psi and also advances the ignition to take full advantage of that extra boost. If you want even more power then the SuperRich Mod raises the boost even further, but this involves uprating the injectors, turbo, MAP Sensor, MAF Sensor, Clutch and Rear Engine Mount!! I would have had that done to mine earlier this year had it not had so many problems

Ã–se480T · Post by **Ã–se480T** » Fri Mar 02, 2007 9:24 pm

OK thank you!!

Would you mind the somewhat high resistance then? 800Ohms... But really, there was no "blinking" with lower settings...

My car must have run really very lean. The setting was at 300Ohms, even lower than the starting setting, and thus not performing that well... The lucky thing is, I didn't realize all the time before and now I feel kind like it's rich-modded now

I will enjoy... It's kinda addictive, like people always say about this car... And of course, after some time, you need more

But first I want to have it running it's meant to...

Before I checked the setting, it consumed more fuel, was weaker in acceleration, but the Vmax was great anyway.. So I didn't think something's wrong... But now, I can drive really sportive and consume less fuel then before... awesome

But I needed some advice/supervision cause I'm not really familiar with all these things yet, as you can see...

By the way, what do you think about adjusting the boost simply with this rod-kind-of-thing, that goes from the turbo to the boost-control-box? One can shorten this rod resulting in more boost, but not too much, because of the fuel-cut and the risk of running lean again... I think the rich-mod has more power then this??

crispy-d · Post by **crispy-d** » Fri Mar 02, 2007 10:13 pm

Hmm - 800ohms is out of the recommended range for MAF settings. I'm not sure why you'd have to have it set that high. Check the voltage reading coming from the lambda sensor, or just fit an air:fuel ratio guage to make sure it's not running too rich. Also keep an eye on the spark plugs, make sure they're not getting covered in soot!

As to making modifications (once you've made certain you're engine is working properly of course) then adjusting wastegate actuator rod is not recommended. The easiest and perhaps most cost effective way to get more boost is to fit a Manual Boost Controller between the wastegate actuator and the boost solenoid (along the red pipe). From what I remember, the most bhp you can achieve from doing this is about 150bhp. This is because the ECU retards the ignition as it sees too much boost. This is why rpruen's ECU mod is much better, as it advances the ignition, giving up to 175bhp. The fuel cut-off happens at 14.6psi, I think, so it won't run lean unless you have defective injectors or there's another problem. That's the final point - an ECU mod leaves all the safety features intact, whereas fitting an MBC prevents the ECU from lowering boost if it needs to. This could be bad if you have a problem.

(With Rich Mod + MBC you can keep up with a new R32

)

Ã–se480T · Post by **Ã–se480T** » Fri Mar 02, 2007 10:35 pm

Alright, I'll do so... And I'll probably measure with another meter, perhaps it's not that accurate... And perhaps, coming down from higher settings I could find the lowest possible setting with the right lambda-sensor response more easily...

And I'll keep the fingers off the wastegate-rod so long..

Many thanks again!

Greetz and bye, Oli..

rpruen · Post by **rpruen** » Sat Mar 03, 2007 9:36 am

Some notes on the CO setting system.

You do indeed need an LED, or a very low curent test lamp. A meter will not work properly. An LED is best as it has the fastest response. I think you will also need a current limiting resistor for the LED. You can also use a dwell meter (if yours works ok with such a slow duty cycle)

The procedure is as follows...

Connect the LED to the test connector, and to the battery. With the engine at operating temperature, and all electrical equipment turned off. Adjust the CO pot untill the LED has equal on and off times (or the dwell is 50%). Allow the engine to run untill the cooling fan switches on, and then off again, then re-check and adjust if required.

Richard

Ã–se480T · Post by **Ã–se480T** » Sat Mar 03, 2007 9:53 am

Ahhh I see that's the point. OK, I'll try with a dwell meter or LED... That's possible, too high a Frequency to detect correctly with a normal meter...

Ã–se480T · Post by **Ã–se480T** » Sat Mar 03, 2007 10:41 am

OK, my dwell meter doesn't work...

I used the avg-function to now get 0,5v directly at the lambda-wire at 450Ohms... I think this is more or less OK until I get a diode to check precisely...

But it feels like double the horsepower and half the fuel anyway

Oese480T · Post by **Oese480T** » Thu May 31, 2007 7:03 am

OK, wanted to post my ongoings again...

Had a leak before the turbo so the maf didn't know of all the air which was getting into the engine, I think thats why the ohms-setting had to be that high .

Now, I get about 500-600Ohms depending on how hot the engine is at the time of setting the maf-resistance... Is this correct? Or do I have another Problem?

I followed richards advise mostly as to set the maf to get the right on-off readings and then let the engine run hot 'till the ventilation sets in and then adjust again. I get about 100 Ohms higher when the engine is at 90Ã‚Â°C compared to 74Ã‚Â°C...

is ist correct to set the maf at the higher temperature in order to prevent running lean on high temps as well as to get things right to enable the ecu to set the right mixture over the entire temperature range?

Thanks again for reply's,

greetz,

Oese..

aibast · Post by **aibast** » Thu May 31, 2007 7:08 am

I set mine to 382, and gives me a realy good milage.

Oese480T · Post by **Oese480T** » Thu May 31, 2007 7:46 am

As far as I know, 382 Ohms is only the starting point for CO adjustance and most often too lean. Of course, the mileage is ok then, but I would like to have it running the way it's meant to do...

at least at my motor, there is a connector, which provides an on-off signal when the mixture is set correctly... And this connector shows "off" all the time when i set my maf lower then 500 Ohms..

I'm already in kind of an argument more or less about this with a friend who promotes 438 Ohms like in his 480

But he doesn't have such a connector and set the maf by trial-and-error to the setting which provides most power...

*confused*

p.s. I think my mileage is ok at my setting, consumes about 6-8L/100km when driving at moderate Speeds around 80km/h in the 4th gear or 140km/h in the 5th... But want to confirm this... So many different opinions on this

Oese..

aibast · Post by **aibast** » Thu May 31, 2007 8:30 am

OK, now weshould sort this thing out, cos I don't want to lean out my cars engine :S

Amonra · Post by **Amonra** » Thu May 31, 2007 11:24 am

about the led blinking thing i cannot understand to which connector the led should be connected. coming out of the MAF i have the 6pinned socket, following the wire bundle from this socket i have two short wires with connectors coming out of the wire bundle.
is one of these the one? if so which one ?
if not where is it ? any pics ?

crispy-d · Post by **crispy-d** » Thu May 31, 2007 12:00 pm

Hope you like the picture - just got drenched taking it

But at least it relieved me of revision for a bit. I wanted to test my new phone camera anyway. The wire's black and blue (not from the abuse I gave it trying to test it mind).

Every car that I've looked at including mine has had it's MAF set to around the 440ohms mark. 382ohms, I found out, is indeed the base setting and then it is to be adjusted until the led flashes on and off with equal intervals, as said.