Date:         Thu, 25 Feb 2010 22:13:42 -0700
Reply-To:     Gregory Smith <gfs@GREGORYFSMITH.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Gregory Smith <gfs@GREGORYFSMITH.COM>
Subject:      Re: 1.9 Digifant with poor milage and low top-end power.
Content-Type: text/plain; charset="utf-8"

Sounds like you're running rich.  Test the temp sensor, you want to see
2500-3000 ohms cold and ~250-270 hot.  Also check the ground near the
A/C bracket.

Without the O2 sensor connected, the ECU cannot adjust the mixture, so
it's "running" off the rough CO% screw setting on the AFM and the temp
sensor input.

Hope this helps.

Gregory Smith

Smith Design Studio
Small Building Company
Olympia, WA
360-239-0429
gregoryfsmith.com


Date: Thu, 25 Feb 2010 16:32:06 -0500

From: Greg Potts <greg@POTTSFAMILY.CA>
Subject: 1.9 Digifant with poor milage and low top-end power.

Hi Volks,

I have been hoping this would get better but it isn't, so I am asking
for
help again.

My 87 vanagon has a low-milage VW reman 1.9 motor wearing 2.1 cooling
and
FI. It idles rock steady, but it is sluggish to respond to throttle, and
low on power until it gets to about 2700 RPM. Lately the top end power
has
also been down a fair bit, enough that at 60MPH it becomes hard to
accellerate on minor grades without downshifting. I am also getting a
bit
less than 200 miles on a 57L (15 gallon) tank of fuel. I used to breeze
up
these same grades without issue and have seen 240-270 miles per tank in
the past.

There is a slight exhaust leak at the forward collector; so I have not
connected the O2 sensor; I know this will have an affect on my milage
but
it shouldn't have so much affect on power output, should it?

So that had me wondering about the brief overheat back in December, so I
tested compression yesterday and got 155/160/160/170. Pretty decent
numbers in my book. Pulling any of the plug wires or injectors gives
instant and dramatic results, so I think I am OK mechanically. I also
checked the throttle body switches and the idle switch engages
perfectly.
I am not able to detect a click at full throttle however.

The spark plugs were bosch platinum and had a nice grey tone to them. I
have heard bad things about platinum plugs on the type2 list so I
replaced
them with some NGK's I had on hand.

Coil, wires, cap and rotor and distributor are just over a year old.

I have a pressure gauge on the fuel rail and it reports about 35 PSI at
idle. When I apply throttle it jumps up to 40PSI until the engine spools
up and as revs increase it gradually drops to about 25 PSI. Once the
revs
are up around 3K it is much more responsive to throttle input. Applying
vacuum by sucking on a hose connected to the pressure regulator will
reduce fuel pressure to 25 PSI until I let go; then it goes back up to
40.

I also have a spare ECU and AFM; swapping them in place makes no
difference.

Suggestions as to what I have missed or what to check next would be
greatly appreciated.

Greg
(No signature when posting from a web portal)