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Weird no crank issue, with other symptoms

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    Weird no crank issue, with other symptoms

    Ok, this is puzzling because it's such a sudden issue. 89 325i 'vert. Everything stock. Battery replaced 2 months ago. No electrical issues prior to today. Driving around, everything fine. Stopped at a store, left car running with my 2 teenage daughters inside. Came out, car idling rough. Went to rev to smooth it out....stalled. Turn key, nothing. No click, no dimming of the headlights, but also, no horn, no radio(turns on and off repeatedly), no dash lights. Turn signals, flashers ok. Checked visible cables and connections. None apparently loose. Closed hood. No start. Got ready to lock it up, getting belongings out. Tried to start again...voila, car is running. Got in, went to drive home(about 2 miles), car is sluggish, won't idle without part-throttle, won't rev above 3500 rpms. About 3 blocks from home, running rougher, finally stalls a block from home. No start issue again.

    Tomorrow I will check the voltages at the battery and starter, and I'll check the main relay, and look at all the grounds. Any ideas of what this might be would be appreciated.

    It was too dark to do any street diagnosis when I got home.

    #2
    I'm no expert but they way it drove home it sound like it may be the fuel pump.
    Edit: or the fuel regulator
    sigpic

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      #3
      Fuel pump/regulator would not cause a no crank issue, which is what it sounds like happened. I would lean towards a bad electrical connection, specifically a higher current ground, somewhere. I've actually seen similar symptoms from loose battery cables, and since you just swapped the battery, it would be an easy thing to check.

      Project M42 Turbo

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        #4
        Well the way he explained it sounded like the fuel pump and if you think it's a no crank issue then probably the crank sensor or both..
        sigpic

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          #5
          So, I walked the block back to my car a few minutes ago. Started right up. :D Revved happily all the way to red line while going for a short drive. Now I have it back home, and I will start checking thru the various items I found here on r3vlimited and on bimmerforums. I will return and post any anomalies I found.

          On an unrelated note: today was the FIRST time in many months that my E30 did NOT exhibit morning sickness(yes, unfortunately it's still an auto). First time it was parked on flat ground too. Usually, I park on the street in front of my house, which is angled no matter which way you park. May try parking a block away on flat ground and see what effect it has.

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            #6
            Alright. Busy day, just got a chance to look some things over right after dinner.

            Car started right up. Ran for about 2 minutes, then, chug-chug-chug-stall. No restart, no crank. Checked battery voltage directly on the posts with my VOM....voila...only 10.92 volts at rest, rising fairly quickly to 11.25 or so. Drops to 4.5 - 5 volts on cranking. Battery purchased 02/17. I suspect the alternator and/or voltage regulator. Additionally, found the ground strap broken at the front hood connection, so I'll replace that.

            This makes some sense, in that I've had a squealing alternator belt at night sometimes, under heavy electrical load, usually on local streets at low speed. Guess I'll be pulling those components to check tomorrow.

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              #7
              Voltage Regulator removed to inspect. Brushes at 4-5 mm. New vr ordered.

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                #8
                So, new voltage regulator installed. Car started, charging at 13.45 volts. Took it for a drive. Stopped at a store. Came out, car won't start. No click, no whir, no sound at all when I turn the key. Measures 10.89 volts at the battery, dropping to 3.5 - 4 volts when the key is turned. Leave it for the day and go home. :(

                Return next day, car starts right up. Measures 11.26 volts at the battery. Get it home, chugging by the time I pull in, stalls as I turn in to the parking space. Turn the key, and nothing.

                Next day(today). Starts right up. Measures 11.35 volts, dropping as it idles to 9.54. Under hood, raising throttle, at 4k rpms, the battery jumps to 13.57 volts, stays there as I come down to 2k rpms, then drops to 11.15, and starts the drop to under 9 volts. Repeat raising throttle. Only seems to kick in the alternator at around 4k rpms, and then drops by 2 - 2.5k rpms. Repeatable, ad infinitem.

                Allowed the car to idle to under 9 volts, turned off key. Tried to start, nothing again.

                Any ideas what is going on with my electrical system? Any way to test my alternator under load?

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                  #9
                  It sounds like you have a bad alternator. At idle you should see ~13.6v, rising to ~14v at 2500rpm. And even though new, you could have a bad battery. Also check the engine to chassis ground on the driver's side of the engine.

                  At a battery voltage of under 12.2v most E30's will not start.
                  The car makes it possible, but the driver makes it happen.
                  Jim Levie, Huntsville, AL

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                    #10
                    Returned battery to Autozone(purchased 03/06/17). Fried. Left with a brand-new replacement. Fired right up. Battery holding steady at 11.99 - 12.02 volts. Took it for a 20-minute spirited run through city streets and on the highway. Car is much more responsive. Returned home, put on the meter, still reading a steady 12.02 - 12.05 volts.

                    Now I need to figure out why the 'battery' light is not lit when the key is just turned on. Suspect the cluster is preventing the exciter charge from reaching the alternator.

                    Is there a way to bypass the battery light, and make a constant connection for the exciter? Inquiring minds want to know.

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                      #11
                      Ok. Dug a little deeper. Amazing what you can try when the battery has a full charge.

                      Used 10 gauge jumper wires clipped to the battery positive and the passenger fender ground, so I could set the vom on the dash and see it while driving.

                      First, measuring 12.21 volts at the battery, D+ and B+ on the alternator, with the key on. NO BATTERY LIGHT lit in dash(nor other lights, but ALL bulbs have been continuity checked ok. In addition, all bulbs swapped with the Parking Brake light, which will illuminate with the Parking Brake engaged.

                      Start the car. Voltage drops to 11.91, and as the idle settles, settles at 12.09 volts. Drive 2 miles to the interstate(25 - 30 mph), stays at 12.08 - 12.09). Enter the interstate on a long uphill right-hander, hit 4500 in 2nd gear, VOILA, vom measures 13.67 volts! Stays in 13.56 - 13.72 range until rpms drop to around 2500, then back to 12.23 volts. Drive the 2 - 3 miles home, vom has settled at 12.18. Stays there with 20 minutes of idling before I shut it off.

                      My cluster is probably toast. Speedo, odo, fuel gauges don't work, and thereby, some of the OBC functions are inop. The no-battery-light exciter issue sucks. And the alternator is probably due for replacement. I'm going to drive to AutoZone tomorrow and have them do a charging system test.:?

                      Any thoughts or suggestions appreciated.

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                        #12
                        It sounds like there is a problem in the exciter circuit, possibly in the cluster.
                        The car makes it possible, but the driver makes it happen.
                        Jim Levie, Huntsville, AL

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