[urq] Fuelsystem diagnostics part3

[Robert A Dupree]

With the LM-1, I would be aiming for lean of stoich at idle and cruise-rpm/load conditions; and at max a 12 ratio (should be headed toward 10 for safety) at WOT at Max Boost at the torque peak of the motor as tuned.

Yes load is the entire key.

Shoot for 15.5 idle @ temp @ 850rpm and the acceptable range would be 14-16.
CIS I don't think can be granularly enough controlled to dial this in exact.
Does your Ur have an EGO loop?  If so once you get it close you can have the LM-1 send a 0-1.5v old-style EGO signal to the Hitachi ECU, and then log the WB data while driving.  That should give you a load driven map of what the WB sees as your effective running fuel profile.  Of course since you can't "add fuel" you can really only subtract boost - so tuning via WB might be really frustrating or show you things you simply don't want to see.

Honestly if you suspect leaking injectors - this is all wasted effort because you'll toss out all results and start over once you are satisfied the fuel-side is producing output within spec...

Just my thoughts..

> -----Original Message-----
> From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On
> Behalf Of Patrick Carlier
> Sent: Friday, October 02, 2009 10:09 AM
> To: urq at audifans.com
> 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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