I haven't found any way to change the curve...yet...without having the
computer custom programmed. ($400+ for a simple timing curve change isn't
feasible.)
And NOPE....no knock sensor that I can find or have heard of on these
engines. The fuel economy theory is nice, but with the pinging problem,
people will have a tenancy to keep their foot in it a little bit more to
quiet it down. Also, when the engine pings that bad, fuel economy goes down.
One interesting thing I found was that in 5th, the engine didn't
ping....only in first through fourth. There's something there which i'm
missing.
- Bernd
At 08:38 AM 04/18/2000 -0500, you wrote:
>I hear ya - isn't that kinda wild to have 36-40 degrees advance almost all the
>time? My scan tool reports the same thing - anytime the rpm's or mph are much
>more than idling and low speed - it jumps way up there. I guess thats how
>they
>get the magnum motors to get better fuel economy (vs LA blocks). It just
>don't
>seem right considering they usually weigh over 4500 lbs. Have you found out
>what the major contributing factor is to the spark advance? It looks to be
>related to TPS, MAP, and/or VS as far as I can tell. I understand that the
>magnum motors don't have a knock sensor and supposedly they sense knock
>via the
>crankshaft sensor or something like that. I don't believe they are using
>anything as I can't see much retard happening at all under heavy load. Maybe
>just a little as the MAP changes drastically but not like it should. I've
>watched the spark advance at the onset of pinging and it isn't changing -
>therefore I don't think they are sensing knock at all. Whaddya think?
>
>Latr,
>
>Shane
>
>ps - on a related note, I did find the magic point at which the system changes
>from open-loop to closed-loop at first startup. Its the oxygen sensor
>voltage.
>Everyone assumed it had to do with ECT but that didn't explain why it still
>transitioned from open to closed-loop while the engine was still hot (at
>startup). Now I know its not related to anything but O2 voltage and most
>specifically - when it makes that first transition past stoich. Cheers!
>
>--
>'96 IndyRam-HisIndy-MPI/TB/Pulleys/Coil/Wires/CompTAs
>'96 IndyRam-HerIndy-numbered(#142)"Track Truck"
>'74 Triple-Black Dodge Challenger Rallye 360 home-brew EFI R&D vehicle
>'68 Black Corvette Convertible 427 (For Sale)
>
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