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    #1

    Surging power....

    I've searched and I can't seem to find anyone with the same problem. on my 87 eta I will go to "romp on it" if you will and it seems to lose and gain power as i go through the rpm's. It's not at the same spot every time but it consistantly loses and regains power. Almost like it will lose 10 or 15 hp and for a second, gain it back for a second, and then lose, and so on and so forth.

    Me and my buddy have been trying to figure it out since I bought the car a month ago and cannot figure it out. But it's driving me INSANE!!! Please if you have any clue of what it could be let me know. Any input will be much appreciated
    87 325e

    Forgive me if I ask stupid questions
    Tags: None
    #2
    Replace the fuel filter if you haven't already.
    It's possible that your cat is clogged.

    Comment

      #3
      typical e30 woa
      -FREEDOM- is cruisin at 80, windows down and listening to the perfect song-thinking "this is it"
      -The Beauty in the Tragedy-
      MECHANIC SMASH!!- (you all know you do it)
      Got Drop?? ;-)
      Originally posted by JinormusJ
      But of course
      E30s are know to be notoriously really really really ridiculously good looking

      Comment

        #4
        My car was having an occasional issue like that. Every now and then it would buck and surge, then everything would smooth back out again. Turned out the crank position sensor was frayed and grounding against the engine block. That would be my bet.

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          #5
          I replaced the fuel filter today and straight black came out when I drained it. It definantly did help but didn't fix it. It's a little milder and once in a while when I get on it (as much as i can in an eta anyway) it doesn't surge. Regardless the filter needed to be changed.

          phenobarb1, I will definantly check the crank position sensor, just curious though where is it? I know in my 240 it was on the top of the bell housing...same on an e30?

          Also my friend seems to believe that my afm is bad. Is that something that would cause this?
          87 325e

          Forgive me if I ask stupid questions

          Comment

            #6
            The first things that I would suspect would be the fuel system, crank position sensors, and AFM. Check the fuel system by teeing in a gauge, tying it to a windshield wiper blade, and seeing what the pressure does while driving. Understand that the DME controls operation of the fuel pump and only runs the pump when it sees timing data from a rotating engine. So a flaky CPS can make it look like there is a fuel system problem. Installing new timing sensors will pretty much eliminate that possibility.
            The car makes it possible, but the driver makes it happen.
            Jim Levie, Huntsville, AL

            Comment

              #7
              The CPS runs across the front of the engine block. It clips into place pretty easily, and can be replaced in about five minutes.

              If changing the fuel filter seemed to help some, I would keep looking for fuel delivery issues. Definitely listen to jlevie, as his advice tends to be some of the best around these parts. If your fuel was really coming out dark or gunked up, it wouldn't surprise me if your injectors were getting blocked up. Replacing injectors isn't too bad though, and fairly cheap.

              I probably wouldn't worry about the AFM just yet. Not to say that they can't cause problems, but it seems to be less common than fuel related issues on the e30's.

              Comment

                #8
                My ETA would accelerate normally up to 2000 RPM, but then if I stomped on it the power would surge - reving to 2200 RPM and holding there for a few seconds, then up to 2400, then to 2600 etc.

                I replaced my O2 sensor and it now rev's smoothly. I think my O2 sensor was old and was switching slowly between voltages, causing the engine to run between rich and lean.

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