Date: Tue, 1 Jan 2002 19:50:07 -0600
Reply-To: Mark Ingalls <ingalls_mark@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Ingalls <ingalls_mark@HOTMAIL.COM>
Subject: Re: B. Bobs day at the dyno and the importance of fuel air ratio
update
Content-Type: text/plain; format=flowed
Bob Said:
>>I have braved the cold this past week and looked over the fuel injection
>>system in my 84 camper with the big valve engine.<<
With a digitool you could have seen the lean condition and the faulty temp 2
sensor, all from the warmth of your van. : < b ( I’m in zero degree
Nebraska )
A recent story of how my digitool and info gained from the list helped me in
troubleshooting a recent warm restart stumble problem. I have the digitool
dash mounted in the after-market dash console, so it’s much safer and easier
to monitor the readings.
It started after I filled with gas one night. As I was leaving the station
and hit 2nd gear I had a couple of slight bucks. I wondered if I had just
gotten some bad fuel. The next few weeks it would occasionally do it, but
usually only on a warm restart.
With a flip of the knob, I was able to watch sensors while the stumble was
happening :
The Afm was steady.
The T2 was correct and steady.
The T1 also correct and steady.
The throttle switch wasn’t shorting out.
The FI pulse was steady.
The 02 sensor read-out was bopping around like it should.
My tach was steady so I knew the coil was being pulsed.
I have an extra ground on the digijet ecu case as well as an extra ground
from the left head to the van body, so I assume my grounds are pretty good.
From being able to watch all these read outs, I was leaning towards either
fuel contamination even though I had been through 3 tanks since it started.
Or Primary Ignition System trouble, like bad plug wires or spark plugs.
Changing plugs was being considered.
I had read in the Bosch FI book that the detergent in fuel is good enough to
keep the system clean but not strong enough to clean built up contamination.
Wondering if maybe some crud had gotten knocked loose when I filled up the
time the stumble started, I decided to try a bottle of high strength FI
cleaner.
As usual with these vans, the stumble has now stopped, it hasn’t done it in
3 weeks of everyday driving. So I don’t really know what was causing it. But
it was great to be able to somewhat eliminate all the above items from info
I’ve gained from the folks on the Vanagon.com list. All it took from me was
to be crazy enough to build Darrell’s dash mounted digitool.
Mark Ingalls
85 GL
75 Beetle
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