Date:         Sat, 31 Mar 2007 12:15:46 -0400
Reply-To:     mordo <helmut.blong@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         mordo <helmut.blong@GMAIL.COM>
Subject:      Surging between 1700 and 3000 rpm
In-Reply-To:  <de48c0be0703251331p5a62285h7395f27f6cdd105e@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I'm bumping this post in hopes for some diagnostic help.

I thinkn calling this condition "surging" was inaccurate on my part. It is
actually just momentary loss of power.

The condition presents with the engine warm, and the engine under load. I
have tested fuel pressure at the T and it is at spec.

I am thinking that the throttle valve switch is a possible culprit. My
question now is what is "full throttle"? If the switch is defective or
misadjusted, would the switch out of adjustment cause this momentary dying
condition under full throttle?

I've just checked continuity and adjustment of the TVS and it appears to
function properly. Given where the throttle is when the the swithc closes
for full throttle, I would guess that the TVS is not related to this power
loss. The throttle valve is open to its stop when the switch closes.

To recap:


   - 2.1L wbx with Vanagon syndrome harness installed
   - Idles fine
   - Under load, at about 1500-1700 rpm, the egnine dies and then revs up
   to about 3000 rpm. Dies, revs. Dies, revs.
   - If I hold the throttle steady it does this very consistently

I'm at a loss. Any ideas?

Thanks,

mordo


---------- Forwarded message ----------
From: mordo <helmut.blong@gmail.com>
Date: Mar 25, 2007 4:31 PM
Subject: Surging between 1700 and 3000 rpm
To: vanagon@gerry.vanagon.com


I just went out for a drive, the third short trip of the day. The van ran
fine the first two trips except on a fairly steep grade near my house. On
this grade, the engine loses power and drops to about 1500 rpm. By
feathering the throttle, I could get it to rev up again and get me home.

This third trip, the engine consistenly surged between abot 1700 and 3000
rpm at about 25-30 mph. This is an automatic 2.1L wbx. Feathering the
throttle seemed to have little positive effect. Accelerate from a stop and
rev up to about 3k rpm - it dies and drops to about 1700 rom and then it
goes right back up to about 3000rpm. A moment later, it drops back to 1700
rpm and so on.

I would be willing to believe it is a clogged fuel filter but why would the
surging be so consistent?

The engine idles fine. The engine is warm, not full on hot.

I checked the fuel pump wiring before this trip. A good wiggle on all
connections did not produce any negative effects. The fuel filter is a clear
plastic, round filter in frotn of the pump. It seems to have some strange
muck at the bottom side of the filter.

Any lucid insights, list?

--
mordo
1990 Carat


--
mordo
1990 Carat