Tuning help needed

[christer.medin at lennoxintl.com]

Aha, that makes sense.  Considering the engine's stumbling _real_ bad when it happens, I guess that a cylinder (or two) may be missing and dumping oxygen into the exhaust as you mention.  The engine running like cr*p probably is what causes the vacuum drop too.  We only had time for a short drive last night, but will go out for tuning a few hours this evening.  A few people have suggested a lean condition causing the whole thing, so I guess the first (and safest) thing to do would richen the mixture up a good bit.

Christer

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From: 	PC :jweir at att.net
Sent: 	Tuesday, June 15, 1999 3:05 PM
To: 	gmecm at efi332.eng.ohio-state.edu
Subject: 	RE: Tuning help needed

Thr only time I get 4 Mv O2 voltage is when I am experiencing a ignition miss-fire.  when a cylinder fails to fire it puts excess oxygen into the exhaust and the O2 sensor senses this as an extreme lean condition (not that you are having an ignition problem).  Sounds like the main fuel table to me... Open or closed loop shouldnt make any difference, I would check either the fuel vs load tables or the accelerator pump tables..

Jason Weir