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I checked the operation of the fuel pump by disconnecting the fuel line at the throttle body. Next I applied 12 volts to the green connector by the Power Brake Booster. This green connector is for fuel pump testing purposes. I had fuel flow. Therefore, the fuel pump is operational. Is it possible that the fuel presssure regulator is bad? Another test would be to check the fuel pressure at the throttle body. There is a tap on the fuel line for this purpose. Any other thoughts to proceed with resolving the problem? Where do I find a fuel pressure guage? Thanks again for your help
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Recently, I noticed sometimes when starting the car, the idle would increase normally and then the engine would stall. This was a clue to a bigger problem to occur. While driving the car last, it suddenly lost rpm and I had to pump the accelerator pedal to keep the car moving forward. At stops, the car would stall and I was able to start it and drive the car about 10 mph while pumping the accelerator pedal. I was about a mile from home when the problem occurred and managed to return home in the car. My first thought was the MAP sensor had failed. After replacing it and installing my spare functional ECU, the problem still exists. The ECU did not store any codes, and the Engine Data Display parameters with the ignition "ON" appear to be normal for MAP, BARO, Coolant, MAT, etc. I do have spark. Now when I try to start the engine, it just cranks, but rarely is there any ignition. Any clues? Speed sensor problem?
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You say you have good blue spark to the spark plugs ?.
If you do, I would suspect fuel pump failure.
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Any auto parts store would carry a fuel pump tester.
I replaced the fuel metering assembly (injectors and pressure regulator) with a NOS part. The car starts after pumping the accelerator pedal. The engine idles fine, and when I depress the accelerator pedalthe engine speed increases normally. When I put the car in drive and depress the accelerator pedal the engine speed decreases and I have to pump the pedal to keep it moving forward. This problem appears to me to be a separate matter. Vacuum? Does you have an idea what is causing this current problem?
AnswerHi George, To get to the bottom of the running problem it is important that you hook up a fuel pressure gauge to the pressure tap on the fuel line behind the throttlebody and see what it reads. Normal pressures are 9-12psi but in my experriance if it isn't 12psi then there is a problem. In your case I would think that your reading might be more to the 9psi area.
The first thing to try would be a new fuel filter and see how it affects the pressure. If still low then the gas tank will need to come down because the pump is inside. At that point you should install a new fuel pump and strainer along with any new hoses and clamps that come with it. A giveaway that the fuel pump is failing is where the wire connector attaches to the pump the plastic will have overheated and turned the plastic a differant color.
Since you asked about vacuum hoses there are 2 areas that need to be checked. The first one is where the air cleaner houseing hose plugs on...you will see a 3/8" fuel hose that plugs in on the rear side. It likes to come off. The second hose is at the rear of the throttlebody at the end of the plastic MAP sensor tube. On the bottom side the hose will burn a hose in it and cause the engine to try to run too much fuel through the injectors.
There is a good possability that there could be several problems but I would start by hooking up a fuel pressure gauge first and see what the pressure is at idle. If the rubber gauge hose is long enough try to tape it to the windshield so you can see what the pressure does when trying to accellerate.
Let me know if you need anymore help. Bill
