The fuel pressure is modulated by engine vacuum. That is the purpose of the vacuum hose at the back of the regulator. The idea of this is to help compensate for the actual pressure difference of the intake manifold versus the fuel pressure supplied to the injectors. As the vacuum increases (real pressure drops) less pressure at the injectors is required for a specific volume of fuel to be delivered when the injectors open. Stmbling problems are usually caused by intake vacuum leaks, uneven fuel delivery (bad injectors), bad intake valves or guides or excessive deposits on the back of the valves. Dennis -----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of jesse johnson Sent: Monday, September 06, 2004 3:18 PM To: vanagon@GERRY.VANAGON.COM Subject: Fuel Pressure Question... Hey All, In trying to find out my van's stumbling issues.. i rechecked the fuel pressure. Seems that i run at right around 30 psi during idle but if i rev the engine.. or hold the engine at say 3000 rpm or so.. the pressure will drop down to like 25 psi or so. Is this normal? Seems to me that it should remain at 29 no matter what the load. This might be why i am having stumbling on take off.. and is worse on hot days. Any thoughts on this? The fuel pump is original and has 170,000 miles on it. thanks all, jesse 89 carat 86 scirocco 310,000 miles and going |
Please note - During the past 17 years of operation, several gigabytes of
Vanagon mail messages have been archived. Searching the entire collection
will take up to five minutes to complete. Please be patient!
Return to the archives @ gerry.vanagon.com
The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.
Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.