Re: My Pinging Problem is Solved!

From: fawcett@uism.bu.edu
Date: Sun Apr 02 2000 - 11:49:00 EDT


Hmmmmm... Pretty exciting stuff! I don't have any noticeable ping but I've
always felt my truck should have more low end. Maybe my MAP sensor is just a
bit off but not enough to ping? Hmmmm... I'll have to check it out.
Thanks Shane.
Tom

______________________________ Reply Separator _________________________________
Subject: DML: My Pinging Problem is Solved!
Author: <dakota-truck@buffnet.net> at smtpout
Date: 4/1/00 10:03 PM

<<snipity, snipity, snip>>

Fast forward to this morning - digital volt meter in hand. KISS - I know
how the MAP sensor should act - skip reading the rest of the diag
procedure. Blip the throttle and it should change right? Its reading
Manifold Absolute Pressure anyway - more throttle - more difference in
the reading... Wheres my truck....Reading voltage on MAP sensor - 3.0V
hmmm - ok rig volt meter so I can start truck and watch voltage while
working throttle. 3.0V hmmm - blip throttle - 3.0V hmmm - nail throttle
to floor (WOT) - 2.99V hmmm. MAP seems to not be responding very well
(understatement). Ok - it doesn't seem to be working with this
arrangement (wondering if my test conditions are valid). Luckily I have
another Indy to check also - rig same MAP test - key on - 5.13V hmmm -
crank truck 4.5V hmmm - blip throttle..wild fluctuation - Bingo!

Start thinking about how this might relate to pinging. My truck with bad
MAP sensor is not able to accurately gauge load - duh - that has to be
it. Final sanity check - swap the known good MAP onto my truck - test
drive - NO PINGING WHATSOEVER! Not only that but huge difference in
power especially in the low end. I promise this isn't an April Fools
joke 8-). Ok now the big test - with a half tank of 87 octane in tank -
drive to Chevron and fill up with 93 octane. Back home - swap computers
to the performance one with more advanced timing - test drive - NO
PINGING!!! Massive power increase also most notably down in the low end
(where I thought my MPI had taken it away).

<<snip>>



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