Date: Sat, 19 Apr 2008 10:12:46 -0700
Reply-To: neil N <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: neil N <musomuso@GMAIL.COM>
Subject: Re: "yawn" Another (trivial) Jetta conversion Fuel Pump relay
question.... ;^)
In-Reply-To: <20080419111119.0232D1165C3@hamburg.alientech.net>
Content-Type: text/plain; charset=ISO-8859-1
Hi Mike.
On Sat, Apr 19, 2008 at 4:10 AM, Mike S <mikes@flatsurface.com> wrote:
> At 09:25 PM 4/18/2008, neil N wrote...
>
>
> > One thing I had to do, was run a jumper between 30 and 86 on FP relay.
> > In Bentley, it shows an internal connection doing the same (though
> > there's no "86" shown):
> >
> > http://tubaneil.googlepages.com/FPrelaydiagram.jpg/FPrelaydiagram-full.jpg
> >
> Because the Jetta relay doesn't have an "86" terminal. I doesn't have 4
> contacts. It sounds like you're using a generic Bosch type relay (4 or 5
> contacts, 2 for coil, 1 for relay arm, 1 or 2 for relay contacts).
Yes. Except for the resistor and larger 30 and 87 contacts, FP relay
is a generic 4 contact relay. It is labeled 167. (came from donor)
Relay numbers listed for fuel pump *and* glow plug relay in Jetta
Bentley are: 67, 80, 167, 102, 104
Here's how I set up 167 relay:
- "Vanagon" B+ to 30
- 87 to FP +
- B+ from relay 30 "jumered" to 86
- Ground signal from ECU to 85.
I think it's wired so that no matter what, if the ground from ECU is
interrupted, the fuel pump will stop running.
I guess I could test that theory once engine is running right. Start
it and pull the ground from the ECU.
Not sure if that would adversely affect ECU though...
> > My potentially trivial quesiton:
> >
> > In diagram on fuel pump relay, there is an icon between 85 and 86. I
> > looked inside and there was a resistor.
> >
> > Why is that resistor there?
> >
> You'll have to provide an image, it's not shown (86) on either of the
> pictures you posted:
> http://tubaneil.googlepages.com/jettafinal1.jpg/jettafinal1-full;init:.jpg
> http://tubaneil.googlepages.com/FPrelaydiagram.jpg/FPrelaydiagram-full.jpg
Sorry. I meant the diagram on the relay itself. Pics of fuel pump and
power relay (click image for larger view):
http://tubaneil.googlepages.com/relays
Interestingly, the power management relay (pic in link further down)
has 4 contacts, but one isn't labelled on the bottom of relay. It only
needs 3 wires as it is internally wired from 30 to one side of the
coil. Similar or same as what you were saying about the FP relay, as
per Jetta Bentley diagram.
> Maybe you're talking about the J17 relay on the second diagram??? Between
> 85 and 30 is the relay coil (electromagnet). The dashed horizontal between
> it and the relay contact arm indicates a mechanical linkage. Contacts are
> normally shown with the relay in the unenergized state, so for this relay,
> putting power between 85 and 30 would connect terminals 30 and 87.
Yes. Was referring to J17 (link originally posted in this thread):
http://tubaneil.googlepages.com/FPrelaydiagram.jpg/FPrelaydiagram-full.jpg
So is the solid line from 30 to the unlabeled contact a connection?
> The resistor which you may find in parallel (across) the relay coil is a
> damping resistor (and is not shown in the diagram), it helps to reduce the
> voltage spikes caused when the relay is de-energized, and the stored
> magnetic field collapses (like happens with an ignition coil).
Ah ok. Thanks.
For sure I saw a 1/4 or 1/8 watt resistor in FP relay #167.
After studying some Bosch relay diagrams online, I found there were
some with a diode incorporated in a given relay. Used for a similar
purpose IIRC.
Thanks for explaining that.
Neil.
