Did you convert to the cooling system with the oil cooler to also cool the
pistons? Detonation is extremely speed and load over time sensitive. The 1.9
FI system should not be a problem, both use the same injectors. Is the
timing set to spec or slightly advanced? Get it set back down. Make sure the
vacuum retard on the distributor is working to reduce the timing during part
load to reduce the peak flame temperatures. Pinging actually occurs long
before you hear it. While pinging, you working at busting rings, melting
pistons, and burning valves or even cracking heads. This is where EGR could
be helpful but the Vanagon does not have it.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Michael Diehr
Sent: Saturday, January 20, 2007 1:02 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Ping/Knock/Detonation

I'm finishing up a long (3K miles) road trip and the van has been
running like a champ (for the first time ever, wahoo!).   However,
I've noticed a problem with pinging (aka knock aka detonation).
It's very particular -- it only happens at 1/2 throttle or higher at
3200 thru 3500 rpm, even on 91 or 92 octane gas.   Happens most of
the time -- only exception seems to be at temperatures of 30F and
lower at 3000F altitude or higher, which seems very consistent with
it being ping (heat & pressure related).

As far as I know, the timing of the engine is good at idle, but I
doubt that the advance has ever been tested.

This is a 85 westy automatic with a newly rebuilt 2.1L block
installed (about 5k miles post rebuild).  It has the stock 1.9FI
system, including a rebuilt computer & distributor & afm.

It seems weird to me that the RPM range is so specific -- it really
only does it at that particular RPM range.  Any ideas?   Bad
distributor advance?   Flat spot in the AFM?   1.9L FI system not
well matched to a 2.1L block?