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On 21 Jun 2006 at 23:23, Mark Healey wrote: > I've had problems with my car running hot for some time now. I've tried > several pressure sensors. The one I have in now is still sealed. I've > checked the fuel pressure, OK. I did the resistance checks on the temp > sensors, OK. > > One weird thing. Somehow air seems to get into the fuel lines. If I > just get in after the car has set for a day or so it takes about 10 > seconds to start. If I run the fuel pump without starting the car for > that 10 seconds it fires right up. > > Could enough air be getting into the fuel lines to cause it to run lean? After you shut down the engine, the heat in the engine compartment causes the gas in the fuel lines to boil, turning it to vapor. This pushes gas back to the gas tank. Once the engine starts to cool back down, a vacuum develops in the lines, which sucks air in any available leak, including the injector tips. The end result is to leave you with a fuel ring full of air. Note that all this air leaked in only AFTER you shut down the engine. There was no air there while the engine was running, so this is not causing your engine to run lean.. This is an almost universal problem with the FI cars, so I don't think it is a sign of running any hotter than normal. Fortunately, there is a simple solution. You can install a switch under the dash to allow you to run the pump for a few seconds before you try to start. You can make up a switch on your own, or I sell an assembly with switch, bracket, wires, and connectors. Some of my own cars have this same problem and they get the under-dash switch solution, too. Once you install this switch, you can listen while the pump runs. It will run for a few seconds, then you will hear air from the return line bubbling up in the gas tank. Once the bubbles stop you're assured that the lines are mostly filled with gas and the engine will start easily. -- Jim Adney jadney@vwtype3.org Madison, WI 53711-3054 USA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~