Date: Wed, 26 Jan 2005 10:55:06 -0800
Reply-To: Robert Keezer <warmerwagen@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Keezer <warmerwagen@YAHOO.COM>
Subject: Re: Question about Mass Air Flow Sensor
In-Reply-To: <41F7A05B.6030405@comcast.net>
Content-Type: text/plain; charset=us-ascii
Ken,
I know a bit about the MAF. The 12 Volt supply is
there for the clean cycle the MAF goes thru when you
shut the engine off. The hot wire or film is heated
red hot to burn off impurities that may have built up
from air intake or crankcase vapors. Large guage
red/blue is hot all the time.
One thing to avoid with the re/blue wire, is not to
connect it to the red/blue coming from the coolant
temp sensor.
These harnesses aren't as uniform as in the earlier
versions or the German made.
So, I connected all the red blue wires and kept frying
coolant temp sensors .
I had a weird stepped idle(Motronic uses a back-up
program when this sensor fails), and then it got
terrible gas mileage and driveability problems.
Red /blue is hot- there are variances in OBD2 . Your
cool temp wire color is Red/Yellow.
Here's a tip- Have a large copy made of the diagrams
-makes it much easier to read.
Robert
1982 Westfalia '95 ABA
--- Ken Wilford <kenwilfy@COMCAST.NET> wrote:
> Mark, do you know what this wire does? It is
> supplying power to the MAF
> but for what purpose?
> I guess I need a little MAF schoolin'.
>
> Ken Wilford
> John 3:16
> www.vanagain.com
>
> mark drillock wrote:
>
> > Ken, according to my Jetta Bentley for that year,
> the MAF sensor
> > red/blue wire you refer to should have power
> whenever the fuel pump is
> > running. It's power comes from current track 16,
> brought to there on
> > relay panel track "a" which comes from the fuel
> pump relay output leg,
> > 4/87 on relay J17. The ECU controls whether the
> fuel pump runs, by
> > controlling the ground leg of the fuel pump relay
> coil 3/85 of relay
> > J17. Of course with a conversion the installer may
> mouse around with the
> > fuel pump control but it is best to do it like the
> factory did so the
> > pump shuts off unless the engine is running
> normally or trying to start.
> > There are a few other devices that also get power
> from the same source
> > so make sure that the other devices with a wire of
> the same color are
> > also connected to it.
> >
> > Mark
> >
> >
> > Kenneth Wilford wrote:
> >
> >> I think I have found a problem with the wiring
> harness on the conversion
> >> I am working on. The wiring harness is from a 97
> Jetta with the 2.0l
> >> ABA engine. Anyway the wiring harness has a four
> wire plug on the mass
> >> air sensor. One of the wires is red with a blue
> stripe. If you have
> >> the Jetta Bentley Manual it is on page 97-297.
> This wire goes to a
> >> group of other wires that are the same color and
> they hook to what is
> >> called "Plus connection in Multiport Fuel
> Injection wiring harness". On
> >> the wiring diagram this is called E7 however the
> wiring diagram also
> >> calls it 87a. What I think is going on is that
> this wire is the power
> >> for the heated air mass sensor. But I don't want
> to hook up power to it
> >> if it isn't supposed to get power as I don't want
> to fry anything. Can
> >> anyone help me figure this out. Also is this
> wire supposed to be full
> >> time hot or just hot when the ignition on.
> >>
> >> This wire was cut and not hooked to anything when
> I got the conversion.
> >> The van runs but only when it is warm outside and
> also it doesn't seem
> >> to have a lot of power.
> >>
> >> Sorry but I am not super familiar with the whole
> mass air sensor thing.
> >>
> >> Any help you can give would be apreciated.
> >>
> >> Thanks,
> >> Ken Wilford
> >> John 3:16
> >> http://www.vanagain.com
> >> http://www.strictlyvwauctions.com
> >> http://www.eurovan.org
> >> http://www.vwcabrio.org
> >> Phone: (856)-327-4936
> >> Fax: (856)-327-2242
> >>
> >>
> >>
> >
>
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