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    Have a quick question

    I have yet to diag this problem but looking for some tips.

    On cold starts my car will start up fine and run like normal. When I start it to drive from work to the gym (15-20 minute drive on interstate and regular roads)
    It will start fine and dandy. But I go to the gym for around 2 hours and come back out. I'll get in and let the pump prime like always but it will take forever to start and eventually struggle to start. It's getting worse by the week and doing it more frequent. When this does occur it's only after sitting for a couple hours to about 4. But once it sits for long periods it's fine. I was thinking it's the regulator in the pump, but it would lose pressure from sitting during a long period.
    The fuel pump was replaced by PO, don't know if whole assembly was or just the pump. This was back in 2012, along with cap and rotor.

    Any ideas and similar problems from anyone? Maybe the crank sensor is nasty from a couple leaks I'm going to fix when parts come in. But if it was the sensor signal it would prolly throw the CEL, but it's off(knock on wood)
    88 d21 draggin pavement
    89 dirty30 kissin earth

    Im just here to learn new things and meet new people.

    #2
    cold switch? controls enrichment at startup, maybe bad
    sigpic

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      #3
      try to recreate the problem but before starting activate the pump (jump the relay) to fill the lines and pressurise it. see if that solves the issue.

      how good are the injectors have they been refurbished recently?
      89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

      new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

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        #4
        I'd also check the coolant temp sensor.

        Comment


          #5
          If your car is an 89 (mentioned in your sig) and it's an i, is or ix then the pump does not prime. The fuel pump relay is switched on by the dme when it senses engine rotation from the cps. You should read 12v at fuse 11 when the (and only when) the engine is being cranked or running.

          This could be your temp sensor, the test procedure is here:



          Also note the last section on the cold start relay, you may or may not have this.

          Bad connections in the C191 plug (under the inlet manifold) could also result in warm start problems. The temp sensor, sender and injector harness all run through that plug and it's prone to rot.

          One other test that is probably the easiest and very common. Warm the engine up to operating temperature, switch off and pull the air elbow. If you see fuel in there your fpr is failing and dumping neat fuel into the intake manifold via the vacuum line. You may also see fuel in that vacuum line if you just pull it off the fpr.

          A fuel pressure test would be ideal if you have the gear. A dead end test should indicate 70 - 80 psi and hold when powered off, if it doesn't then your fuel pump non return valve is done. An inline test should indicate 35 - 40 psi and hold, if it doesn't then the fpr is leaking either into the manifold, a bad injector or return line. Pressure will vary depending on the pump you have fitted - it may not be oem.
          Last edited by Seawolf; 11-05-2016, 10:21 AM.

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            #6
            An answer-

            leaking injector(s).

            Try to 'flood clear' it by cranking with the pedal floored first.

            t
            now, sometimes I just mess with people. It's more entertaining that way. george graves

            Comment


              #7
              Thanks guys for the replies.
              Cleaned the crank sensor, was covered in oil from valve cover leak. This and other leaks will be fixed next Saturday. Seems to start better all the way around. I poured some liqui moly fuel system clean and that has brought my fuel mileage back up.
              88 d21 draggin pavement
              89 dirty30 kissin earth

              Im just here to learn new things and meet new people.

              Comment


                #8
                Even if the fuel system check valve was bad, allowing pressure in the fuel system to fall after the engine is turned off, if the pump, filter, and FPR are in good condition the rail pressure will return to normal after a few turns of the engine when starting. But such a failure would just as evident on a cold start as when the engine is hot/warm. So that doesn't seem to be the mail problem.

                This sounds more like a flooded engine from a defective FPR or, more likely, leaking injectors. If the engine sits long enough the fuel in the intake or cylinders will evaporate or drain past the rings., allowing the engine to start.

                I'd start by replacing the FPR and having the injectors professionally rebuilt and tested (I like RC Engineering).
                The car makes it possible, but the driver makes it happen.
                Jim Levie, Huntsville, AL

                Comment


                  #9
                  How often do the FPR's go bad? I thought about that going bad.
                  88 d21 draggin pavement
                  89 dirty30 kissin earth

                  Im just here to learn new things and meet new people.

                  Comment


                    #10
                    I can't say how often FPR's go bad, but it isn't an uncommon problem.
                    The car makes it possible, but the driver makes it happen.
                    Jim Levie, Huntsville, AL

                    Comment


                      #11
                      Originally posted by Bggdnssnguy View Post
                      How often do the FPR's go bad? I thought about that going bad.
                      I have had a few go bad over the years and a handful of E30's.

                      So it isn't as common as new spark plugs, but it does happen.
                      My previous build (currently E30-less)
                      http://www.r3vlimited.com/board/showthread.php?t=170390

                      A 2016 Toyota Tacoma TRD 4x4 Offroad in Inferno is my newest obsession

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