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1997 Lincoln Town Car Question: No Start Sometimes

 

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RR007, Wake Forest, NC, April 20, 2011, 07:31
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Intermittant problem of no start has been occuring for the past 12 months. Everytime this occurs I spray ether, 2-4 seconds, into intake and it starts up everytime and continues to run with no problem. I take trips to NY and FL and there is NEVER a running problem. If it starts when I turn the key it immediately fires up and runs. Other times when I turn key it immediately cranks over but without any hint of firing. I then ether it and it fires up immediately and runs fine until I have to stop and shut it off. Sometimes it will continue to start correctly everytime for the day and several days after. But sometimes when I have a small trip to a store it will not restart when I get out and I have to ether it to start again.

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  • Answer #1

    Creech Import Repair Incorporated (24 Answers) , Raleigh, NC - (919) 813-7305
    CreechImport April 20, 2011, 08:21
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     Technician

    If it starts with starting fluid then I'd suspect a bad fuel pump or fuel delivery issue. One symptom of a bad pump is what you've described in that the pump just won't rotate or develop pressure when voltage is applied. Checking fuel pressure when it won't start, and checking for voltage/ground at the pump will verify the solution.

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    RR007, April 20, 2011, 12:07
     Rookie

    Creech,
    If it is a bad fuel pump, why does it run 700 miles to Tampa, Fl or 600 miles to Buffalo, NY without a problem? I can believe more that it is a fuel delivery issue which is SOLVED by causing the engine to fire up on ether. Once this happens the computer controls sense the engine start and start the fuel injection and the engine runs normally. What I can not determine is what the computer control is looking at as far as an input that would cause it to not fire the injectiors during the cranking process. The only physical thing that happens when the engine fires is that there is a large increase in manifold vacuum. Is there a sensor which might not get sufficient vacuum during cranking but would if the ehgine fired up on ether? I have read that the TPS and the Idle Air Solenoids are sometimes culprits in this process?

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    CreechImport, April 21, 2011, 07:06
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    It's been my experience that when a fuel pump fails, it will fail to "start pumping" on initial start up, not stop pumping while driving down the highway. I looked at a wiring diagram and the ecm controls the fuel pump power input. It's possible that once the engine starts using starter fluid, the vibrations and increased system voltage (charging voltage) may be enough to get the pump going. Try to verify fuel pressure when the no start condition exist. It should have 35-45 psi within a second or 2 of turning the key to "on" position. As far as injector pulse, we use noid light tools to check for injector pulse. You just unplug one injector and connect the noid light, spin the engine over and watch the light for flashing. That would indicate injector pulse. If you don't have one you might check at a local parts store like Napa, Carquest or Advance Auto.

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    RR007, April 24, 2011, 18:31
     Rookie

    Creech,
    I hooked up pressure gauge and turned ignitin to ON. The first time I read 30 psi and when I tried to start it started. However, after letting it sit I returned and turned it to ON and read 27 psi but it did not start. Had to ether it to start and it ran fine but pressure was 26 psi. Later came back and now it read 20 psi and it did not start and had to ether it and it started and ran fine at 28psi. Next test was... turned ignition ON with fuel pump relay jumped out at terms 30 and 87 which it ran continuously. Pressure was 27psi and it did not start. However I heard the regulator making a low sound. I used a screwdriver to ear at the regulator and heard fuel running back to tank. This should not happen as by spec it should be 30-40 psi regulated pressure range. Will replace regulator and retest. Will let you know what happens.

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    DaveJHM April 20, 2011, 21:44
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     Master

    RR007,

    I think you're working too hard! Have you done the basics - a fuel pressure test, a fuel pressure bleed down test? Can you confirm there is no fuel pressure up until you add the ether and start the engine? That would be the best place to start.

    Usually the problem is not so difficult to discover. There are indeed countless possibilities and theories, but the most obvious ones are usually the cause.

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    RR007, April 24, 2011, 18:15
     Rookie

    The fuel pressure was at 28psi and it did not start. Put ether in and it started up but pressure remained at 28psi. Another test with ignition turned on and fuel pump jumped in at relay( connected term 87 to 30) and running continuously pressure did not increase but remained at 27-28 psi. However did hear fuell running thru regulator back to tank. Will try replacing the regulator as it should hold pressure at 30-40psi. Will get back after this replacement and retest.

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    DaveJHM, April 24, 2011, 21:12
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     Master

    It's a bad pump. Pure and simple. Fuel pressure way to low to start quickly enough or to maintain proper running.

    Like I said, you're trying too hard. I can't think of a single fuel pressure regulator I've replaced on any 1991-1997 Town Car (essentially the same car).

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