[urq] Fuelsystem diagnostics part3

[Patrick Carlier]

I forgot .

It's not the US 'typical' .
It's an EU spec WR , wich is compleately open loop .
Doesn't even have an oxygen sensor .

I think this is the main difference between WR and WX engines .

Guess I'll just have to wait until I can take it on the road
to measure AFR under real conditions .

Thx
Pat



----- Original Message ----- 
From: "j.koenig" <koenigj at comcast.net>
To: "Patrick Carlier" <p.carlier at pandora.be>; <urq at audifans.com>
Sent: Friday, October 02, 2009 6:02 PM
Subject: Re: [urq] Fuelsystem diagnostics part3


>I can't remember whether your car is something unusual, but if it's the 
>'typical' U.S.
> spec, I think you also have to look at duty cycle, which is fixed by the 
> control module
> under certain condition, and the idle and wide-open-throttle switches, 
> which are inputs to
> those fixed values.  If you set things up without those switches and/or O2 
> sensor feedback
> loop working properly, I think you can get to a place where going to 
> open-loop operation
> has the opposite of the desired effect on mixture.
>
> I haven't thought much about this since working on my own car a while ago, 
> so, my
> two-cents-worth only (experts please comment).
> Good luck.
> John
>
> ----- Original Message ----- 
> From: "Patrick Carlier" <p.carlier at pandora.be>
> To: <urq at audifans.com>
> Sent: Friday, October 02, 2009 11:09 AM
> Subject: [urq] Fuelsystem diagnostics part3
>
>
> Today I took an intemediate step .
> I should do the injector leak and yield tests .
> But I decided to try and adjust the mixture strengtht first .
>
>
> I don't have a four gas analyser , but I do have a wideband .
> Innovate LM-1 , nice toy for a decent price .
>
> So I started the engine , wich fired at the first crank :)
> Allowed it to warm up and hooked up the wideband .
>
> Idle mixture was waaaay to rich .
> In fact it was so far off , it's a surprise the car would start .
> Anyway , I adjusted to 14.60 , wich should be close to 1% CO at idle .
> But then if I open the trottle just a bit an run the
> engine at 3000RPM , AFR readings drop an remain steady
> at 12.30 .  No that's pretty rich isn't it .
>
> If started leaning the idle mixture to 16.50AFR .
> Can't go higher cause idle becomes erratic .
> Stilll , at  3000rpm I  get an AFR OF 12.85 .
>
>
> Could it be that this rich condition is due to racing the engine with no 
> load .
> I can't take it on the road yet to do some real testing .
> Does anyone know what AFR should be under normal driving conditions ?
>
> Pat
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