Date: Sun, 22 Feb 2004 17:01:30 -0800
Reply-To: mark drillock <drillock@EARTHLINK.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: mark drillock <drillock@EARTHLINK.NET>
Subject: Re: Misbehaving in the wet
Content-Type: text/plain; charset=us-ascii
What you have is the typical bad OX sensor wiring symptom. The ECU
IGNORES the O2 reading for a minute or 2 after you start a cold engine.
This is because it knows that the engine needs a rich mixture when it is
cold so there is no point in it using the O2 reading until warm-up has
occurred as the mixture is intentionally too rich. The engine runs fine
for a few minutes until the ECU starts trying to use the O2 feedback to
adjust the mixture. Then the engine does not run right because the ECU
sees a faulty signal on the wires and adjusts to mixture too much to try
to get the reading into range.
The several times I have seen Vanagons with this problem it was usually
due to the use of a generic replacement O2 sensor that had splices in
the wires. The splices worked fine when dry but rain would cause
problems. Other times it was a problem with the O2 signal reference
ground wire. That ground wire is in the bundle with the ones that
connect to the side of the distributor but the ground goes to a nut on
the engine near the distributor. It is often run to one of the oil
breather tower nuts.
Mark
Brad Estergaard wrote:
>
> Hey List,
>
> Long post ahead....
>
> For a long time now I have had a problem with my 88 Syncro whenever I have to drive in the rain/wet snow. Everything runs fine while the engine is cold (5-10min) but as soon as things warm up a bit (and are wet) I get severe 'bucking', loss of power with no response to the gas pedal, and eventual stalling. The symptoms disappear immediately if I shut down and restart (or a rolling re-start :) ) but will come back within a few minutes.
>
> I do have the updated harness so it should not be the standard vanagon syndrome problem.
>
> If I disconnect the O2 sensor either before I start-up or after the symptoms develop this "usually" buys me some more time before the symptoms return (like 10-15 minutes instead of 1-2min) and in some cases when the 02 is disconnected I can 'ride-out' the problem as the symptoms will sometimes suddenly disapear again after a minute or 2 if I can keep the van running for that minute or two (have to be travelling on the highway with enough speed to have that kind of time).
>
> I have also noticed that the ISCU gets wet and on casual checks I don't think my ISV is hummimg or vibrating but from what I understand these components only matter while the engine is cold or if you have AC.
>
> In case it is related, my idle is erratic as well. In the dry it is usually around 1000 but can surge to 2000 when warmed up. When its wet and I have the O2 disconnected it generally stays at 2000 when warm.
>
> The last weird thing is that while this is happening, and until the van has had time to dry out (overnight), my non-working gas guage starts to sort of work...it will move up to 1/4 tank. When I fire up the van and the gas guage stays below empty I know that I will not have a problem. I cannot make sense of wiring diagrams but I am wondering if and where the fuel guage and the FI system might share a wire?
>
> Any ideas? I'm at the point where it seems I should just replace all the FI components (everything is original btw and almost at 250,000kms) but is there an order i should follow...like O2 then Temp2 then Throttle switch etc. Or could it be an electrical problem of a differnt kind (grounds) or something totally different? Any hints or theories appreciated.
>
> regards,
> Brad
| 
