Fuel pressure reg/EGO Qs

[Rich M]

Andy,
Yes, I've had some success with a standard ego sensor - BUT, you have to be
aware of and accept the limitations:
Realistically the ego sensor will really only tell you rich or lean, due to
the hysteresis, it's difficult to get a stable mid range reading.
>From my experience on both injected (1800-2000cc 4cyl port inj.) and
carburetted engines, (2000cc 4cyl. Weber progressive dual-choke and twin
sidedraught DCOE's) you can get a pretty good first shot with a standard ego
sensor. If mixture is rich or weak the ego signal will be at one end or
other of it's range; when it gets close to stoich. the signal will probably
hunt back and forth due to the hysteresis (this at least is my experience).
With the engine in a steady state, off load (few k's rpm) I have been able
to adjust mixture finely to get a mid-range reading from the ego sensor, but
it's difficult to get these conditions while driving.
Don't be fooled by indications of weak mixture resulting from misfires! A
rich misfire will generally give a "weak" reading because of the excess
oxygen in the exhaust from the misfire!
I have no doubt there will be those who disagree with these methods, but
these are my findings by experience, it will get you pretty close. If you
need better, then it's a trip to the chassis dyno with multi-gas analyser.
At least you'll know you're not piston-melting-weak or bore-washing-rich, in
fact you can close enough that your chassis dyno tuner won't need to do too
much.
The sensor I'm using is a Bosch 4-wire heated sensor mounted in the bottom
of the exhaust downpipes/headers where all the branches meet.
Hope this helps.

Rich.

> -----Original Message-----
> From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
> Behalf Of Andy Wyatt
> Sent: 11 February 2000 06:47
> To: diy_efi at diy-efi.org
> Subject: Fuel pressure reg/EGO Qs
>
>
> Hey y'all
>
> 2. Has anyone tried to use a standard EGO sensor to tune an engine? I'm
> currently trying it, but it has so much hysteresis that it isn't working.
> How do factory ECUs do closed loop control, esp at idle?
>
> Cheers
> Andy W :-D

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