Date: Mon, 11 May 2009 19:40:26 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Digifant Fuel System Troubleshooting Experience
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I believe there is a check-valve in the output of the fuel pump.
Once pressurized.........the fuel pressure should stay there for quite a
while ( engine not running, but pump has run and brought pressure up )
The pressure should stay there for days even, ideally.
New pump sounds in order to me..........
and............I must say, how great to read a well thought out and properly
pursued, *and explained* diagnostic procedure !
Now there is a poster that can be helped.........someone that includes
plenty enough pertinent information, and their thinking process..........
AND !! - they write in complete and grammatically correct sentences !!
So nice to see - though it might make me faint from shock. But
really........a well written and educated sounding post ....
with really good tech thought and info .........much appreciated, let's just
say that.
re checking injectors -
I just do the visual spray test as shown in the Bentley manual - it's super
easy to do - just hang the injectors out of the engine, disable the high
voltage ignition , jumper the fuel pump to run in the black box above the
ignition coil...........
and here's a nice trick ....instead of cranking the engine on the starter to
fire the injectors,
I either just pull the distributor and turn it by hand, or......even
easier - just grab a spare distributor, pull the connector off the side of
the engine's distributor, plug that into the spare one, and holding it in
your hands, turn it, to fire the injectors ( key has to be on of course ) .
I went through 10 injectors recently - the yellow colored .........out of
10 I got only 4 used injectors with a nice spray pattern.
That particular van passed a smog test just 'A + ' right after that. It
has a good OE type cat on it too.
We could/should be checking injector spray pattern much more often I
suspect. Many of 'em are over 20 years old after all.
A high quality fuel additive once in a while can't hurt either.
Scott
www.turbovans.com
----- Original Message -----
From: "Don Hanson" <dhanson928@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, May 11, 2009 6:52 PM
Subject: Re: Digifant Fuel System Troubleshooting Experience
> I'd say, "a new pump"...But I sometimes have a dumb habit of 'throwing
> parts
> at a problem". But you will then have a somewhat servicable spare pump to
> carry along if and when you travel...Another thing to check is the
> condition
> of your fuel lines and hoses. Make sure they aren't "fixed" somehow
> dangerous by that PO and see if they've ever been replaced..Many a vanagon
> has gone up in flames from old leaky fuel lines...You might have some
> leaks
> there causing your fuel pressure to bleed off.
> Don Hanson
>
> On Mon, May 11, 2009 at 5:54 PM, Dave Arthur <dave.arthur@nscc.ca> wrote:
>
>> I hope I never get to be one of those PO (Previous Owners). I hate it
>> when
>> technicians(?) take short cuts and 'make it work'.
>>
>> I've been tracking down an uneven idle and decide it was time to do a
>> test
>> of the injectors. I work at a community college and borrowed an OTC kit,
>> it
>> consists of a pressure gauge and an electronic device to manually fire
>> the
>> injectors.
>>
>> The procedure is to fit the pressure gauge into the fuel system, turn on
>> the
>> ignition to pressurize the system (pump should shut off after 5 seconds),
>> note the fuel pressure and then fire the injector (50 pulses at 1 ms per
>> pulse was suggested), note the resulting fuel pressure and calculate the
>> drop. All the injectors should have approximately the same drop which
>> correlates to fuel passed through the injector. Now of course it doesn't
>> evaluate pattern etc. but its a fast test.
>>
>> So I set up and turned on the ignition, the fuel pump runs continuously
>> and
>> doesn't turn off after 5 seconds. Being a new Vanagon owner I thought
>> that
>> this was normal... But I'm now suspicious.
>>
>> I checked the wiring diagram and see that the pump is actually run
>> through
>> a
>> relay, that is controlled by the ECU. I removed the relay, turned on the
>> ignition and the pump still ran. Turns out the PO/Tech had run a wire
>> from
>> terminal 15 on the coil directly to the pump. So ignition on, pump on.
>>
>> This of course is a huge safety issue ...
>>
>> I replaced the relay and connected the pump up properly and all was well,
>> until I checked the fuel pressure. As soon as the pump stopped the fuel
>> pressure bled down rapidly to zero (~2-3 sec). The manual expects at
>> least
>> 29 psi after ten minutes!
>>
>> I pinched off the fuel return line and individual injectors to test for
>> leak
>> down issues and concluded that the pump itself was not holding the
>> pressure
>> when it stopped.
>>
>> So the engine runs, but starts hard, with the pump running all the time
>> as
>> before, the engine started immediately.
>>
>> I guess I need to know my options. Could I put a check valve in the
>> pressure
>> side of the fuel line or should I bite the bullet and get a new pump?
>>
>> Dave
>>
>> '86 Westy
>>
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