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Re: Fuel isses and high idle Posted by Saana88 [Email]  (#207)  [Profile/Gallery]
(more from Saana88) on Sun, 29 Jul 2007 08:51:49
In Reply to: Fuel isses and high idle, Jeremy Mauro, Sun, 29 Jul 2007 00:12:46 Members do not see ads below this line. - Help Keep This Site Online - Signup |
If the usual vacuum leaks are taken care of, I doubt it's the fuel pump unless you're getting odd or unusual noises from the back.
However, I did have the same problems when my fuel pressure regulator died. It's a barrel-shaped device on the end of the fuel rail. The rail attaches to the four injectors and to the fuel line going back to the pump. How many miles are on this car? I've had those regulators tend to fail every fifteen years or 120-150k pretty typically. The diaphragm inside is constantly exposed to fuel so eventually it will not make a seal anymore. Symptoms from the last failure included fuel supply problems, hard starts requiring full throttle, confused idle, and occasionally a little fuel pump noise.
When that part failed, the computer was not able to open up the fuel injectors for the right amount of time anymore. Mine failed full rich, meaning the injectors were forced to slow down the fuel supply constantly. The oxygen sensor kept telling the computer "too rich!" (it was right) but every time an injector pulsed open it would inject too much fuel. The computer was bouncing back and forth from "too rich" to "must open injector" to "that was too much" and may have even been shutting down the fuel pump. The tech that put the car on the fuel pressure gauge said the fuel system pressure was maxed out all the time, a good sign of a failed regulator. The regulator adjusts from fuel pump pressure in the line to a usable pressure for the fuel injectors based on the amount of intake manifold vacuum (the same as the amount of load on the engine) so unless you're at wide-open-throttle (high load, no vacuum) the FPR usually decreases the fuel rail pressure and the injectors can retain more fuel. The vacuum line leading to the regulator sucks back the diaphragm inside and sends some fuel back to the tank via the fuel return line at low load, high vacuum situations.
A new FPR for you should run around $65, formerly less but the Dollar is weakening. You should be able to replace it yourself with common hand tools and cleanliness.
, Sun, 29 Jul 2007 08:51:49 <-- Viewing This Message
, Sun, 29 Jul 2007 15:39:41, Mon, 30 Jul 2007 10:53:39
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