RE: Re: MAP Info

From: Ronald Wong (ron-wong@home.com)
Date: Thu Nov 16 2000 - 13:53:26 EST


But.....

Everyone that is trying to fool the system, so to speak, is talking about a
"performance modification". Based on that, I would have to guess that in
most cases they don't care about closed loop numbers, other than to maintain
a consistent idle. The rest of the time they're trying to see if their foot
can fit in the crankcase. Does that mean that people running HP PCM's
already have the tables updated, though, there is no adjustment available?
Would adjustments to an HP PCM be helpful as in the VEC 1?

Ron
00 SLT QC 4X2 5.9 46RE 3.92 LSD
For modifications see my DML Profile

-----Original Message-----
From: owner-dakota-truck@buffnet.net
[mailto:owner-dakota-truck@buffnet.net]On Behalf Of Bruce Bridges
Sent: Thursday, November 16, 2000 10:44 AM
To: dakota-truck@buffnet.net
Subject: DML: Re: MAP Info

To add my thoughts...
The MAP signal is used to calculate the load value for the engine (along
with the TPS, IAT, etc...) The load value is used to determine enrichment,
timing and the onset of Open loop. A high signal (low vacuum) is normally
associated with a higher load.
For WOT, If you can increase the onset of the load determination (or delay)
you will affect the onset RPM of the open loop mode. You are not in direct
control of the pulse width or the timing, the PCM is still doing that job,
but it will react differently if you, for example, place the zero voltage at
a normally lower voltage than expected once the computer zeros the
transducer. This will speed up open loop determination and enrich the
mixture as well as pull back the timing. If you increased the span on the
tranducer, you will delay the onset of open loop and effectively lean out
your mixture longer than "normal" increasing timing and response. Im not
sure what else you can do , but then again Im not an OBDII software
expert..Im not sure how much effect the MAP has on Open loop performance
once its in Open loop...
Bruce
----- Original Message -----
From: <bernd@texas.net>
To: <dakota-truck@buffnet.net>
Sent: Thursday, November 16, 2000 3:55 AM
Subject: DML: MAP Info



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