Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site mcnc.mcnc.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!whuxl!whuxlm!akgua!mcnc!jwb From: jwb@mcnc.UUCP (Jack W. Buchanan Jr.) Newsgroups: net.auto.tech Subject: Re: diagnostic problems with VW fuel injection Message-ID: <976@mcnc.mcnc.UUCP> Date: Wed, 6-Nov-85 15:50:29 EST Article-I.D.: mcnc.976 Posted: Wed Nov 6 15:50:29 1985 Date-Received: Fri, 8-Nov-85 22:09:55 EST References: <476@harvard.ARPA> Reply-To: jwb@mcnc.UUCP (Jack W. Buchanan Jr.) Distribution: net Organization: Microelectronics Center of NC; RTP, NC Lines: 22 Summary: I have more experience than I wished in low cost debugging of this type of injection system. As you implied, you HAVE to measure the pressure to know what is going on. If you are willing to not measure the pressure to the accuracy all the manuals say is necessary then the following is one way. Find one of those cheap foot operated tire pumps with a dial type guage on it. Unscrew the guage, connect it to a piece of fuel line and, using a T fitting (I used a plastic one designed for vacuum lines-metal would surely be better) insert it in the fuel line. The guage covers the right range (I recall something like 40 or 50 psi). You can read it to about 2 psi and the accuracy is probably 2 or 3 psi (the manuals say you need to know to 1 psi). In my case the mechanical regulator failed stuck open allowing full (electric) fuel pump pressure (about 100 psi). Replacing the regulator fixed the problem. The shop manual implied that failure usually resulted in low pressure, which seems to be what you have. As you have no doubt found out, the cheap fuel pressure gauges cover much lower pressures and are designed for mechanical fuel pumps in non fuel-injected systems. My experience is on a 280 Z, but the system is simile2to yours. Good luck! Jack Buchanan UNC-Chapel Hill {decvax, akgua}!mcnc!jwb