Date: Sun, 9 Apr 2006 15:43:38 -0400
Reply-To: Brian Keese <brian.keese@STILTMART.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Brian Keese <brian.keese@STILTMART.COM>
Subject: Re: digijet FI adjustments
Dennis or anyone,
I found this thread in the archives. It describes the situation with my 84
1.9 digijet.
I occasionally have surging at idle, especially immediately after a warm
start. How can I correct that?
Unplugging the O2 sensor and/or the idle stabilizer doesn't stop the
surging. I have set the throttle idle switch, timing and idle speed as per
the Bentley. The Temp II sensor was replaced a couple years ago, as well
as the grounds being checked (but I couldn't find one on the right-side
head). It was running great without this surging until I had to reseal the
heads a couple of months ago. The surging started after that job was
complete. I can't find any connectors that I missed, and I'm almost
certain all the vacuum lines ended up in the correct places. I might have
a vacuum leak somewhere near the throttle body. I can't tell if it really
is a leak, or if it is just air whooshing through the throttle opening.
Today I tried simply screwing in the idle adjustment screw until the
surging subsided. I haven't tried yet to drive it or to start it cold with
this new idle setting.
The van is performing great otherwise, so I haven't worried too much about
fixing this. Should I worry?
Thanks for any advice,
Brian
On Mon, 11 Oct 2004 08:32:19 -0400, Dennis Haynes <dhaynes@OPTONLINE.NET>
wrote:
>If you have the Bentley and a good Digital volt-meter and a timing light
you can do it. The Digijet requires very specific set up for the throttle
plate, ignition timing, idle speed and CO. The adjustment on the AFM is
only to help trim the adjustment at idle. Basic setting are as follows:
>
>Engine close to operating temp.
>With engine off, disconnect 02 sensor and bypass idle stabilizer.
>Check throttle plate adjustment. Adjust stop screw so it does not stick
closed. Idle air goes through bypass screw. Check operation of throttle
switch or switches. Adjust as needed.
>Start engine, adjust timing to proper mark at idle speed. Check vacuum
advance operation. Opening throttle should quickly advance timing. Further
check, remove vacuum retard hose, (one directly to manifold). Timing must
advance. If not, hoses are wrong, diaphram is bad, or throttle plate not
adjusted properly. Find cause. Adjust idle speed to ~950 rpm.
>Using voltmeter, check O2 sensor voltage, (still disconnected). Should be
about .5v. If no reading, rev engine for 30 seconds to heat sensor. Adjust
AFM to get .5v. Just get it close. Slightly lean is better. Adjust idle
speed again if needed.
>Shut off engine, reconnect stabilizer and O2 sensor. Restart, and check
O2 sensor operation. After 30 seconds or so, you should be able to see it
working.
>
>On occasion, you may have surging at idle, especially after a warm
restart. If you do, I'll tell you how to correct that.
>
>Dennis
>
>
>
>----- Original Message -----
>From: Darren Lastfogel <dlastfogel@PLYFORMS.COM>
>Date: Monday, October 11, 2004 7:40 am
>Subject: Re: digijet FI adjustments
>
>> Ok I replaced the O2 Sensor, temp 2 sensor, checked fuel pressure
>> 32 psi,
>> adjusted RPMs to about 900 and checked all vacuum connections, now
>> it runs
>> fine after warm up(stalls when cold)Still runs rich, but better.
>> Back to the
>> CO adjustment screw Bentley just says adjust. Adjust to what? is
>> it in for
>> lean? or out for lean? or should I leave it to a mechanic? I was
>> thinking of
>> buying the JCW fuel ratio gauge to monitor.
>>
>> -----Original Message-----
>> From: dhaynes@optonline.net [dhaynes@optonline.net]
>> Sent: Friday, October 08, 2004 8:59 AM
>> To: Darren Lastfogel
>> Cc: vanagon@GERRY.VANAGON.COM
>> Subject: Re: digijet FI adjustments
>>
>>
>> This is not an adjustment problem, something is wrong. Most likely
>> culpritis the temp 2 sensor or the connection to it. Check ground
>> connections etc.
>> Rich running after warm is probably bad O2 sensor.
>>
>> Dennis
>>
>> ----- Original Message -----
>> From: Darren Lastfogel <dlastfogel@PLYFORMS.COM>
>> Date: Friday, October 8, 2004 7:18 am
>> Subject: digijet FI adjustments
>>
>> > Good morning Listees
>> >
>> > Last night I installed new exhaust gaskets because the PO never
>> > put any on,
>> > It always ran fine just sounded bad. Now it sounds quiet. This
>> > morning I was
>> > on the way to work and it was running very rich then after I turn
>> > it off I
>> > could not get the engine to start. My question is where do I
>> > adjust the air
>> > to fuel so the engine will lean out? and where is a good starting
>> > point?
>> > Darren
>> >
>>
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