Date: Tue, 29 Aug 2017 02:32:01 +0000
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: 2.2 engine hiccups at 3300 rpm
In-Reply-To: <172AC1FF-C858-48F5-84DE-141ED6600AEB@gmail.com>
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There are a lot of things that can cause the hiccups or engine miss even at a given speed range. It is extremely unlikely that it is the air flow meter. I recently had a van with hiccups with changing engine load. Turned out to be the wire connection at the alternator that feeds the fuel injection. That one kicked my but for at least a week.
Point is you need to do some real trouble shooting and just changing parts is not the way to go. Changing parts can often mask bad wiring or connectors where just moving things made a change but the fix does not last so next time a symptom appears one just moves on to the next part.
For these hiccups I would begin by suspecting the O2 sensor circuit. The fast easy test for this would be to cycle the ignition off and back on while still moving. If the hiccups disappear for a short while than most likely the sensor is weak or the system has an electrical problem causing the ECU to make the mixture too rich. At this point changing throttle-speed may get the engine above or below that critical choking point.
For all the vans I have worked on I have only actually fixed three with an air flow meter. And those three had the meters opened up and tampered with They really don’t go bad and you can’t reliably test them with an ohmmeter. I have also found that the fuel injection often gets blamed for running issues and that it is not the problem. The ignition system can also cause all sorts of grief even from something as minor as a crack (carbon trace) in the distributor cap or rotor.
Dennis
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From: Dennis Jowell<mailto:dennisjowell@GMAIL.COM>
Sent: Sunday, August 27, 2017 6:16 PM
To: vanagon@GERRY.VANAGON.COM<mailto:vanagon@gerry.vanagon.com>
Subject: Re: 2.2 engine hiccups at 3300 rpm
Thanks Dan I have a replacement AFM I will try tomorrow
Dennis Jowell
Scotch Hollow Farm
Newbury, Vermont
> On Aug 27, 2017, at 4:40 PM, Dan N <dn92610@gmail.com> wrote:
>
> so it's not altitude related...
>
> besides what I suggested to do/check ... I'd think that the carbon tracks on the AFM were worn at the 3K/3.5K rpm spot (that's where the contact sits most of the time) ... if it's the case then you will need and a rebuilt AFM or have yours rebuilt... unless you want to do it yourself...