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Fouled spark plugs 900 93

posted by  someone claiming to be Ed Colandra on  Tue Dec 5 12:54 CST 2000 [RELATED]

G'day friends...

For the second time in about 6 months, my wife had trouble getting her 93 940 started. I removed the plugs, cleaned them with starter fluid and a little emory paper, regapped, and reinstalled. These plugs have less than 10K on them, but the wires and cap are older. I looked through the FAQs section, but can't draw any conclusions. Basically, the plugs are soaked when I take them out, and black. I clean em up, put em back in, and she starts right up and runs fine again...

Thoughts, advice appreciated...

ED in NJ







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    Re: Fouled spark plugs 900 93

    posted by  someone claiming to be Gene Stevens on  Tue Dec 5 15:20 CST 2000 [RELATED]

    How's the gas mileage??

    Black plugs indicate rich running. If it's running rich all the time, gas mileage will be poor, and I'd guess a failing fuel pressure regulator.

    If it's a cold running problem, I'd check for out of value (or dirty connection to the) coolant temperature sensor.

    You may be able to get a fault code out of the diagnostics. If there are no codes set and the FPR is good, you may have a weak ignition coil, but it's rare.







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      Re: Fouled spark plugs 900 93

      posted by  someone claiming to be Ed Colandra on  Thu Dec 7 07:42 CST 2000 [RELATED]

      Anyone know of a reliable on-line source of a fuel pressure regulator for a 93 940...?







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      Re: Fouled spark plugs 900 93

      posted by  someone claiming to be Ed Colandra on  Wed Dec 6 10:17 CST 2000 [RELATED]

      Here is the dumb question of the day..Where is the fuel pressure regulator..? I don't even know what it looks like...?







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        Re: Fouled spark plugs 900 93

        posted by  someone claiming to be Steve on  Thu Dec 7 02:50 CST 2000 [RELATED]

        It's on the fuel injector rail, right up front. Besides the connection where it slides onto the rail, there is a return hose to route the excess fuel back to the tank, and on turbos, a small vacuum hose going to the intake manifold.

        If the diaphragm in the regulator leaks slightly, you'll have fuel passing into the vac hose, or if the valve sticks shut the pressure is too high. Either way, the engine runs too rich.

        Start by checking the small hose for evidence of gasoline - there should not be any.







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          Re: Fouled spark plugs 900 93

          posted by  someone claiming to be steve on  Thu Dec 7 04:26 CST 2000 [RELATED]

          My gas mileage has bee suffering lately so I have been following this thread and I have a (maybe stupid) question too: How does the FPR fit on the fuel rail? Does it just press on, so once I undo the bolt and fuel and vac lines, I just pull it off the rail?







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            Re: Fouled spark plugs 900 93

            posted by  someone claiming to be keefus on  Fri Dec 8 06:56 CST 2000 [RELATED]

            It just pressure fits on the end of the fuel line. There is a little rubber donut seal that fits into fitting. Two bolts on mounting bracket hold it snug.







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              Re: Fouled spark plugs 900 93

              posted by  someone claiming to be Ed Colandra on  Sun Dec 10 14:02 CST 2000 [RELATED]

              Just a thought...I replaced the dist cap, wires and rotor on my wife's 93 940 this weekend...To say the least, they were in pretty bad shape..

              Could a weak spark cause fouling..? I also replaced the plugs with Bosch Platinum 4... I don't see any visible signs of gas on the FPR hoses..

              Thoughts/comments are always appreciated...

              Thanks,

              Ed in NJ






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