Date: Tue, 19 May 2015 08:48:31 -0700
Reply-To: Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject: Re: Start up,back fire?
In-Reply-To: <1E2AAE99-0AFA-469E-90C7-AE195F8F9D72@gmail.com>
Content-Type: text/plain; charset="US-ASCII"
That's not the cause of your backfire, and as long as the plug didn't blow
out along with the threads, no damage done.
If you haven't yet, check the timing. It's done at 2000 rpm, so it helps to
have a helper (see the Bentley). Check for a fuel leak though, I really
think that's it since it only does it on start up. First, pull the vacuum
hose on the fuel pressure regulator and see if there is any gas in it, there
shouldn't be. Then move on to the injectors. Personally, I think you should
just have them all rebuilt, it runs about $20 each from Rock Auto and
others.
It might be a good idea to do a compression test too. Engine warmed up, all
plugs removed, and the throttle held fully open. Another thing that can
cause a backfire is an intake valve that doesn't close, but it wouldn't be
running well if that were the case.
Stuart
-----Original Message-----
From: Dennis Jowell [mailto:dennisjowell@gmail.com]
Sent: Tuesday, May 19, 2015 3:10 AM
To: Stuart MacMillan
Cc: vanagon@GERRY.VANAGON.COM
Subject: Re: Start up,back fire?
Decided to change spark plugs on my new GOWESTY engine and found out that #1
cylinder spark plug was loose. The compression washer on the plug was not
compressed and was on an angle with dirt between the washer and plug. Could
this have caused my backfire issue?
Plugs where installed by the mechanic who installed the engine.
Disappointing !
I also changed the distrib cap and rotor.
Dennis Jowell
Scotch Hollow Farm
Newbury, Vermont
> On May 16, 2015, at 2:37 PM, Stuart MacMillan <stuartmacm@GMAIL.COM>
wrote:
>
> Right, but it saves time to first learn if there is a fuel system problem
at all. If there is, then you can pinch off the fuel hose to the left
injector bank and determine which side is leaking, and pinch off the
pressure regulator vacuum hose to test it. I hate taking things apart
unnecessarily!
>
> Stuart
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Larry Alofs
> Sent: Saturday, May 16, 2015 10:10 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Start up,back fire?
>
> It seems to me that if the fuel pressure leaks down too quickly, the cause
could be an injector, the fuel pressure regulator, or the fuel pump. The
first case is more serious than the last two. You need a way to tell which
it is.
>
> Larry A.
>
>
> On Sat, May 16, 2015 at 11:35 AM, Stuart MacMillan <stuartmacm@gmail.com>
> wrote:
>
>> Easiest way to do the fuel leak down test is with a fuel pressure gauge.
>> Bentley says system should hold pressure (30 psi or so) for several
>> minutes after shutdown. If your gauge comes with an open hose
>> adapter, slip it over the fuel tap near the distributor, and use a
>> clamp. Otherwise cut it and splice it with a brass barbed coupling
>> for other cars. Get the type that drains any residual gas out a
>> separate line. Instructions here, including safety procedures:
>> https://www.youtube.com/watch?v=QsqBJxKj1KQ
>>
>> Do it soon, backfires are hard on the AFM. I've used mine many times
>> over the past 40 years to diagnose fuel system problems.
>>
>> Stuart
>>
>> -----Original Message-----
>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>> Behalf Of Dennis Jowell
>> Sent: Saturday, May 16, 2015 3:19 AM
>> To: vanagon@GERRY.VANAGON.COM
>> Subject: Start up,back fire?
>>
>> Question on why do I sometimes get a backfire from my 2.2 GOWESTY WBX.
>> yesterday I drove the 88 gl Westy an 1.5 hr pulled over to check my
>> GPS, shut the engine off. Then 2 minutes later started it and "bang"
>> it backfired, it did start. Shut it down and tried again same thing.
>> Drove home it didn't occur again. Any thoughts of what is going on?
>> The new Engine has about 5000 miles on it. Maybe to many mice running
>> around in there.
>>
>> Dennis Jowell
>> Scotch Hollow Farm
>> Newbury, Vermont
>>
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