Date: Tue, 16 Jun 2015 17:22:35 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Engine hesitates upon take off
In-Reply-To: <006801d0a7c6$132f1400$398d3c00$@net>
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The fuel pressure regulator actually modifies the fuel pressure with changes in manifold pressure, (vacuum) Normal pressure is around 25 psi, high vacuum when throttle closed to around 32 psi engine loaded and throttle open. This transition is important as the O2 sensor will trim out at idle and you want the throttle opening to increase the fuel pressure to get the fuel flowing.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Jack Reynaert
Sent: Monday, June 15, 2015 7:51 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Engine hesitates upon take off
Could be your fuel pressure regulator (OE Part# 025133035), as the engine accelerates more fuel is sprayed into the cylinder by spraying for a longer period of time. The fuel injection pressure regulator is designed to maintain a set fuel pressure (between 25 and 60 lbs.) no matter if you are idling or accelerating.
If it isn't idling right, then a more costly fuel injection idle air control valve (OE Part# 025906457A), which modulates the air mixture entering your engine at idle. If you car has a rough idle or is unable to idle without use of the accelerator pedal, you should inspect this valve for any obstructions and clean or replace as necessary.
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Rick Cooper
Sent: Monday, June 15, 2015 10:25 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Engine hesitates upon take off
I've noticed that when accelerating from an intersection, after sitting at a red light, my 2.1 WBX will sometimes hesitate for 5 to 15 seconds. I'll start moving, but the engine has no power and giving it more gas does nothing. After those few seconds, the engine will start to pick up power and soon everything will be running fine.
This has just start happening and is still sporadic, but it is becoming more frequent. Seems to only happen after a full stop, like at a red light. Would this be a clogged fuel filter or what?
Thanks for any ideas. FWIW, the fuel tank and the ECU were replaced a few years ago.
Rick
