Re: Low O2 readings in Diacom at WOT.... please help!

[romans@starstream.net (Romans, Mark)]

Stock injectors and stock ecm should be in the 11 ms range on an 87 vet at
torque peak.  When I had mine in the 12ms range it was pig rich. Less is too
lean.  You have some other problem.  See what the commanded afr is when at
wot.
Mark
----- Original Message -----
From: "Marteney, Steven J." <smarteney@xlvision.com>
To: <gmecm@diy-efi.org>
Sent: Wednesday, May 31, 2000 1:16 PM
Subject: RE: Low O2 readings in Diacom at WOT.... please help!


> Yet again, I'll poke my unknowing head in and say something sounds fishy.
> My limitation is not knowing enough about the 87 Vette, but 7ms sounds
like
> a pretty long PW (Diacom reading) for a TPI 350.  Don't know the size of
the
> injectors in this car but my stock 89 TPI 350 ran a typical pulse width of
> 2-3 ms.  Now, with its ZZ3 cam it is running 4-5ms pulse widths (Diacom
> reading again.)
>
> Doubt this helps any, but what the hey!
> Steve
>
> -----Original Message-----
> From: Craig Marcho [mailto:test@airmail.net]
> Sent: Wednesday, May 31, 2000 2:42 PM
> To: gmecm@diy-efi.org
> Subject: Low O2 readings in Diacom at WOT.... please help!
>
>
> I hooked up Diacom on a buddy's '87 Vette this past weekend. During idle,
> everything seemed normal. O2's were ranging from 100 to 800, up and down
> like they should. But, when he hit WOT, the O2's went to 40 and stayed
> there!!! Injector pulse width's were about 7ms when they should be about
> 9-11ms at WOT. The car is bone stock. It runs great, too. What would cause
> this? Is the O2 bad? It seems fine during idle and closed loop operations,
> but just when you hit WOT and the BLM goes to 128, they drop to 40 or so
> until you let off the throttle. TPS voltages seem fine, too.... .55 at
idle,
> and 4.65 at WOT. No codes. Any help is appreciated! If you want the Diacom
> file, I can email it.
>
> Craig M.
> --------------------------------------------------------------------------
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