air/fuel gauge reading interesting

[potatonet 0]

Installed a duostyling AFR gauge into my car last night. I let the car warm up and it idles in the "ok" range... when I step on it it stays in the ok range until about 2500 rpms till about 5000 rpms where the reading will greatly fluctuate between lean and ok, it goes back and forth rapidly. I will post a video when i get the chance... anyone know what causes this?

[Riley 0]

not sure m8 :(

 

mine cycles between ok-rich.

 

only time it reads lean is when i let off throttle and coast/slow down.

 

neil.

[potatonet 0]

mine is going loony between lean and ok but at rising rpms...

[potatonet 0]

here are my vids, the rattles you hear are the camera, the golve box, and the new catalytic converter that now rubs on the inside wall... just look at the RPMs and the air to fuel ratio gauge, see how wacky the thing is? I know the gauge is fine cause the idle video says its rich then says its not rich when I let go... kinda funky.... stevemac, this happen to you when ure full throttle switch went out?

 

http://home.ripway.com/2005-8/401890/MOV00682.mpg

http://home.ripway.com/2005-8/401890/MOV00683.mpg

http://home.ripway.com/2005-8/401890/MOV00684.mpg

http://home.ripway.com/2005-8/401890/MOV00685.mpg

 

SOMEONE PLEASE TELL ME WHAT IS WRONG!

this is why my car doesnt stop overheating.... =-/ I think... otherwise I blew a copper headgasket... no thats not possible...

[h100vw 0]

The output on the gauge should be steady when you first start the car. As the lmbda probe warms up then the output hunts up and down as the ECU is using the signal to keep the mixture within limits.

 

Once up to temp and at idle the gauge should be cycling rich, lean, rich. This confirms the output is good an that the ECU is controlling the engine correctly.

 

As you set off, not using full throttle. You will see the gauge intially go rich, if you hold the throttle steady while accellerating the mixture should cycle again. Each time you change gear, assuming you come well off the throttle, the gauge will indicate lean as the ECU will cut the fuel briefly as the load drops.

 

With a steady throttle at any speed the gauge will cycle, from experience the faster you are cruising the quicker the cycling is.

 

When you go WOT the gauge will most likely go lean briefly but should then climb up into the rich section. Don't expect it to go off the scale.

 

If you are running anything but an SNS chip don't be surprised to see it cycle for a few seconds before heading rich. This is digilag, with an SNS chip this is removed, so they indicate rich straight away when you go WOT.

 

 

If your WOT switch went then the mixture would always cycle. The point of the WOT switch is to send the ECU open loop. ie it stops monitoring the exhaust gas, you can't have max accelleration with a lean mixture. The amount of time the throttle is wide open is insignificant and doesn't affect emissions, in the scheme of things.

 

Gavin

[potatonet 0]

rgr that, so the cycling is ok then, neil do you have an SNS chip, I have a neuspeed getting a sns 5.5 soon... =-/ I hope that its ok, must have blown the copper headgasket with 16 lbs of boost... oh well time for a rebuild at 140k anyway...

[potatonet 0]

now it cycles between lean and ok.... the ohms are set at 530 for the CO pot... =-/

[stevemac 0]

now it cycles between lean and ok.... the ohms are set at 530 for the CO pot... =-/

Lean when at "wide open throttle" ?

 

Noticed the problem with my duff throttle switch when the car was being re-mapped. Couldn't get enough fuel into the engine at "wide open throttle". Throttle switch wasn't sending a signal to the ECU to richen the mixture.

 

Can't see your vids - bandwidth exceeded.

[potatonet 0]

you must save them or give PM me with your e-mail address so I can send them to you. those are from 2 days ago when the CO pot read 490 ohms, it now reads 530, I might adjust it back to that, I just got a new Catalytic converter and I didnt want to kill it...

 

if you see the vid it only cycles between 2500 and 4500 rpms roughly then it goes to ok or rich...

 

the first movie still works but its the 4th one that needs to be viewed, PM me with your email address or if someone has a solution to online video sharing then please PM me...

[Riley 0]

rgr that, so the cycling is ok then, neil do you have an SNS chip

 

yeah mine cycles as above,but never from lean>rich,its always ok>rich this is once warmed up and applying throttle/not wot.

 

i presume thats ok?

 

i have a superchip at the moment m8,sns is on the way though :D

 

neil.

[kevin 0]

fitted mine today and at idle it it goes from, lean / ok,lean /ok.

could it be a faulty lambda probe/ wiring.

regards kevin

[Riley 0]

mmmm,maybe its mine thats reading wrong? :?

 

i did test the lambda the other week and it was fine,c.o is bang on 0.5% etc...

 

neil.

[kevin 0]

mmmm,maybe its mine thats reading wrong? :?

 

i did test the lambda the other week and it was fine,c.o is bang on 0.5% etc...

 

neil.

seems a bit weird this as i checked my lamda as well and it was fine, could always be a bad wire/connection as when mines cold it reads ok but as soon as it warms up it goes ballistic lean /rich

kevin

[kevin 0]

just been on the duostyling web site and they tell you that it should function very quickly,and at idle it should read between lean and ok

http://WWW.duostyling.com

and click "support" lots of info on there

regards kevin

[Riley 0]

weird. :?

 

only thing i can think of is that,my lambda wiring was a little frail,but didnt 'seem' to affect the drivability or the voltage readings.

 

while its been off the road ive spliced a new connector on from a passat gt,so ill see if theres any difference and report back! 8)

 

edit:just seen your second reply!

 

seems mines the problem one then :(

only time it reads lean is when im totally off the throttle.

 

neil.

[potatonet 0]

well something is up with my car for sure, had it tuned at 530 ohms and starting my car I would press the gas and the car would sputter and backfire for a few seconds till It got used to the gas then it was fine... I changed it back to 490 and drove it for a while, turns over without sputtering now... too lean I guess, gauges look to be reading ok during the day, at night they go ballistic in the lean range tho... =-/ just got to replace that tranny now I guess, also I might have blown the headgasket running lean with no second gear, so I have to high rev 1st and then go to 3rd... kinda sux....

[h100vw 0]

Fellas, you are all getting hung up on the gauge. If it cycles at all then the probe is ok. Going lean when off the throttle is NORMAL, the ECU cuts the fuel on the over-run to save it. It cuts back in about 1500 revs to stop the engine stalling.

 

At the end of the day these gauges are just a 'flash' voltmeter, manufacturing tolerances will mean they often indicate differently.

 

The main point of having one IMO is to see whether the mixture has gone seriously lean, ie off the bottom of the scale, whilst you are thrashing the engine to the red line. The rest of the time, it's nice to see at a glance that your LAMBDA probe is working. Of course what you tell folk down the pub is another thing. :mrgreen:

 

Before you fitted it you didn't have to worry about it, so don't is my advice.

 

Gavin

[potatonet 0]

yeah I am worrying a lot now that I see it all the time... =-(

[h100vw 0]

You need to see that it is not running lean. THE ONLY WAY to do that is with a gas analyser and the easiest place to do it is on a rolling road.

 

You need to stop looking too deep. :)

[potatonet 0]

rgr that, will get it adjusted at the expensive guys to make sure its done right...