Ideas on stoppin some pingin?

Peter Serwe peter@easytree.net
Wed, 9 Jul 2003 07:55:19 -0500


Gonna take a stab at this, I had this problem,
and it's since gone away.  Anyone feel free to
correct me if I misspoke

> Only happens on wider open throttle positions such as going up a hill

Yeah, at WOT, the knock sensor has no effect,
the ECU doesn't retard timing past at either WOT,
or above 4500rpm.  I'm not sure at which point
the TPS calls it WOT, but I think it's at 70% or so.

WOT is also open loop mode, meaning, the ECU no
longer adjusts the mixture to stoichiometric.
and runs the mixture at FULL rich.  This is why a dry
nitrous kit can work, because the activation is controlled
by a little switch that only gets hit at WOT.

> While in 4th/3rd gear, while there is a higher load on the engine.

All this car geek stuff is fun and all, but the fix is so simple,
and non-tech, it's hilarious.

At the suggestion of another LM, I ran a bottle of
Chevron Techron through a tank of gas.  By the
end of the tank, the issue had disappeared.

The carbonization buildup on top of the pistons
and in the combustion chamber effectively increased
compression to the point where I was detonating
all the time, base timing at 15.  The real clue for me
was that even without being at WOT, I would hit
4500rpm, and like a switch being thrown, instant
detonation.

After the bottle of Techron, timing's at 19 btdc,
and it never detonates, not at redline, not at WOT.

At $10, it wasn't bad at all for price/performance.

> Help me out boys :)

Hope that's all the help you need, for your sake,
detonation is EVIL.

--
Peter Serwe <peter@easytree.net>
Cheaper, Faster, Better, pick any two.
finger peter@easytree.net for public pgp key