Update on L-98 Pinging

David A. Cooley n5xmt at bellsouth.net
Thu Nov 5 01:35:56 GMT 1998


At 06:56 PM 11/4/98 -0500, you wrote:
>I talked to Performance Resource today and they have reprogrammed a portion
>of the chip where I was having a severe ping with my 90 Vette.  They stated
>that they pulled out 3 degrees of advance and richened the mixture.  My
>question is, this is a low speed problem, i.e., pulling at 1/3 to /12
>throttle from 25 mph to 35 mph.  If the engine is closed loop, how can you
>alter the mixture so it is richer.  Is there a table for desired AF ratio
>to match the BLM numbers?  They also want me to move my MAT sensor from

They probably made the ECM go to Power Enrichment sooner...

>where I re-located it (intake tubing) to the stock location in the TPI
>plenum.  This will signal the ECM that the air is warmer.  Wouldn't this
>tend to lean out the mixture?  

It mainly affects timing... The warmer the MAT, the less timing the ECM
gives...
This may be how they remove 3 degrees of timing!

Later,
Dave

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           David Cooley N5XMT           Internet: N5XMT at bellsouth.net
     Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
       I am Pentium of Borg...division is futile...you will be approximated.
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