Date: Thu, 31 Jul 2003 19:40:50 +0100 From: Grunff <grunffnopsam.com> Subject: Re: Mixture problems and lumpy idle
Paul Halliday wrote: > The noise is a hissing, almost fizzing noise and from the outside seems to > be inside the fuel tank. In the boot, I couldn't smell anything and upon > lifting the sub-floor, the hissing gets much louder. When I got home, I > unbolted the sub-floor completely and turned the engine on, but the idle is > spot-on and no hissing. Is this the fuel pump starting to die? A gentle hiss is quite normal for the in-tank pumps - two of my cars have always hissed, but the pumps are fine. When they start dying, they make some horrible groaning noises. You'll know it when you hear it. > Now, where was I going with this ramble? That's it! I presume a pressure > test would show up a faulty fuel pump. Not necessarily. A pressure test would tell you if the pump isn't delivering fuel at the right pressure, which is a good start. But a dying pump, where the motor bearing's on it's way out may still deliver good pressure. > Where would I plumb one in? The flexible fuel pipe as it comes into the engine bay, and joins the fuel regulator. > I'd > prefer something I can look at all the time, like an in-dash gauge (or maybe > leave the gauge in the engine bay) - where would be good to put the sender? > I think the sender would fit into a pipe insert with a UNF type of fitting. > Bugger, soon I'll have more gauges than Saab's other Aeros :) Don't know how common fuel pressure gauges with remote sensors are. When I measure fuel pressure, I just hook up a regular pressure gauge with a hose. Not a good permanent arrangement though. -- Grunff