Date: Sun, 28 Dec 2003 10:20:57 -0500
Reply-To: EMZ <vw4x4@FYI.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: EMZ <vw4x4@FYI.NET>
Subject: Re: Air Fuel Mixture Logic
In-Reply-To: <3FEEE530.326E7CF2@cs.fiu.edu>
Content-Type: TEXT/PLAIN; charset=US-ASCII
I would check for vacuum leaks. Injector seals, manifold gaskets,
vacuum lines, rip in boot. These are all places that you can
have vacuum leaks.
Eric 86-VW4x4
vw4x4@fyi.net 86-SS Syncro
Pittsburgh, PA USA 1936-Chrysler
92-Jetta GWC
www.fyi.net/~vw4x4/vw4x4.htm
On Sun, 28 Dec 2003, Jeff Strickrott wrote:
> Hi All:
>
> I am in the process of fixing all the teething problems of bringing up a
> new engine for my Federal 82 Vanagon (2.0L type IV engine). I am still
> the process of trying to get the engine to idle well and set the air
> fuel mixture. I am looking for some suggestions or comments on my
> reasoning process.
>
> Current situation:
> - the FI system checks out and fuel pressure is to specification.
> - valves were readjusted (after they pumped up) and compression is now
> 110-120 in all cylinders,
>
> Problem: Can't get the car to idle well enough to set the timing using a
> timing light or the mixture using a O2 sensor.
> - To start the engine I have the timing statically set at 7.5 BTDC.
> - Idle mixture screw 8 (half turns) open and the CO mixture screw mostly
> closed. These were the settings from my old engine.
> - The car will immediately start but will need the throttle to be held
> open to continue to run (at about 1500 rpm). If I do not hold the
> throttle open the engine will die. Vacuum at 1500 rpm is about 15 InHg.
>
> By my reasoning, I am running too rich so I need to give the engine more
> air. I have tried opening both the idle screw all the way and leaning
> the mixture at the AFM. This improves thing slightly, but still requires
> more air (by opening the throttle). If I now vary the timing I can get
> the engine to idle (poorly), but the timing must be advanced around
> 16-20 to get this to happen. Vacuum decreases when I do this.
>
> By opening the throttle I am also delivering more gas. So maybe it is
> not the mixture at all but something to do with the injector spray
> pattern. I have not checked this since the old engine was removed, but a
> year ago they gave me a nice conical pattern. They were stored dry as
> not to gum up.
>
> So what does the community think the initial problem is? Any ideas on
> how to proceed?
>
> Thanks for the help in advance.
>
> Regards,
> --Jeff Strickrott
> 82 Westy, South Florida
>
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