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Thread: Z3 Won't Start –*Buzzing Noise, No Crank

  1. #1
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    Z3 Won't Start –*Buzzing Noise, No Crank

    Hi, everyone. Longtime reader, first time posting.

    I recently completed an engine swap on my 1997 BMW Z3 roadster. I took the 1.9L m44 out of my car (it had developed rod knock) and switched it with a 1997 318i m44 engine. We swapped the entire wiring harness and fuel pressure regulator from my car and kept my DME. The new engine burned through a few starters, but on the third starter, it started and ran just fine for three days. On the fourth day, it would not start, just making the clicking or buzzing noise that some of you have described in this forum. Here's what I've tried:

    – Swapping out fuel pump relay in driver's side kick panel.
    – Swapping out starter for another new (remanufactured) starter.
    – Swapping out one fusible link next to battery with a 120 amp heavy-duty stereo fuse from Pep Boys.
    – Recharged battery (band-new red-top Optima) and also jumped Z3 with a running car.
    – Checked and replaced fuses #30 and #31 in fusebox.

    The car will push start in second gear, which makes me think it's not an EWS problem (correct me if I'm wrong). I called the BMW dealership and they said that a replacement key would be about $70, so I might go that route next, along with replacing the ignition switch and EWS antenna. Is there anything else I should check?

    Nearing the point when my girlfriend is hinting I should sell the car. Just spent… a lot on the engine swap, so I really want this to work. Thanks in advance.
    Last edited by forestcasey; 02-08-2017 at 01:10 PM.

  2. #2
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    Doesn't really sound like an EWS/Keys problem.
    -Abel

    - E36 328is ~210-220whp: Lots of Mods.
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  3. #3
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    Is there a second fusible link that I need to change out on my era E36/7? Something has to be interrupting power from the battery to the starter…

  4. #4
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    Welcome to the forum! Sorry that you're having issues with your Z3 - I've attached a DIY tech article from our site on the ignition switch replacement and also a general link to help you troubleshoot issues in the future. Post a Comment just below one of the articles if you need additional help or more of a tech related answer and someone will get back to you. Best of luck!

    Ignition Switch Replacement

    BMW Z3 E36/E37/E38 (1996-2002) Technical Articles


    -Dmitry
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  5. #5
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    Hi, Dimitry, thanks so much. Have definitely read that Ignition Switch replacement article before – I've been operating my ignition switch with a screwdriver for the past few years (I've had the same spinning key problem that many of us have for years), it's seemed to work just fine thus far, though I have a backup switch already in case it stops working.

    Another interesting thing – on my last drive home after being push-started, I put my driver's side window down and it won't go back up. Could the entire ignition problem have something to do with the General Module IV? I've replaced this in the past when my windows weren't working – don't know if it also has an impact on the starter. Thanks again for your help!

  6. #6
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    You can push start the car? Definitely not an ews problem.

    Focus on the actual problems, such as the rigged ignition, engine wiring swap (grounds checked?), clutch switch...
    -Abel

    - E36 328is ~210-220whp: Lots of Mods.
    - 2000 Z3: Many Mods.
    - 2003 VW Jetta TDI Manual 47-50mpg
    - 1999 S52 Estoril M Coupe
    - 2014 328d Wagon, self-tuned, 270hp/430ft-lbs
    - 2019 M2 Competition, self-tuned, 504whp
    - 2016 Mini Cooper S

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    Quote Originally Posted by forestcasey View Post
    Hi, Dimitry, thanks so much. Have definitely read that Ignition Switch replacement article before – I've been operating my ignition switch with a screwdriver for the past few years (I've had the same spinning key problem that many of us have for years), it's seemed to work just fine thus far, though I have a backup switch already in case it stops working.

    Another interesting thing – on my last drive home after being push-started, I put my driver's side window down and it won't go back up. Could the entire ignition problem have something to do with the General Module IV? I've replaced this in the past when my windows weren't working – don't know if it also has an impact on the starter. Thanks again for your help!


    No worries at all man - I suppose it could be tied into the module itself or the regulator - are you able to get any codes read? Like another member suggested, I would def go through the electrical system and make sure everything was situated correctly.


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  8. #8
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    One code reader showed that I have to replace the Knock Sensors (I'm showing a CEL because of that), though I don't think that would keep the car from starting. When I took it to an independent BMW mechanic, apparently their code reader showed a battery drain somewhere, though I hoped I fixed that by replacing the fusible link in the trunk.

  9. #9
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    Did you make sure the terminals are clean and snug? If you turn on your interior lights/gauge lights, do they flicker or dim when trying to start? I don't think it's going to be a major issue. Also, is the connection to the starter snug? The buzzing sound reminds me of when a starter is not receiving sufficient power. You can also try "tapping" the main part of the starter to see if maybe you are at a dead spot on the windings, and you might also want to make sure the pinion is getting extended on it (just in case you're describing a sound differently).

  10. #10
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    Yes, we polished off the battery terminals with a powered wire brush, the cabin lights are strong and don't dim after being turned on (I've experienced this in the past). Even pulled the battery, gave it a full charge and re-installed it in the car. Starter wires are definitely snug – haven't tried tapping while starting recently, but that hasn't worked in the past. Buzzing sound is (apparently) the fuel pump, and that starts when the ignition switch is turned to accessory mode. Then it makes a clicking noise when I try to start it, but the starter doesn't engage. Weird.

  11. #11
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    I'm drawing the wiring diagram now. I could screenshot it, but that's probably illegal or whatever. Have completed the EWS II portion, but can't upload a picture yet because 1) potato phone, 2) work laptop with no SD slot.

    EDIT: If you have the keyless entry box behind the glovebox, please unplug it so I can leave it out LOL. Car doesn't care if you unplug it.
    Last edited by LannVouivre; 02-08-2017 at 06:42 PM.

  12. #12
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    My 3000 mile guess is the ground strap on the right engine mount arm is likely loose or missing.


    /.randy

  13. #13
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    Randy waited until I finished my (beautiful) diagram. I suppose a poor connection between the engine and chassis ground would also cause issues, sheesh. I'm still posting my diagram when I get home for others. It's specifically for the 97 1.9L manual; there's like a difference of 1 wire color and 6 or so pin locations between 96, 96, and 2.8L.

  14. #14
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    Randy, that's the engine mount strap that's next to the exhaust headers on the passenger side of the car, right? I looked at that today, seemed secure, but probably need to crawl under the car and yank on it to make sure.

    You guys don't think it could be any sort of issue with the DME recognizing the 318i's m44 engine, right? The fact that it worked sporadically for a while really makes me wonder... Thanks so much again for your help!

  15. #15
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    Buzzing while trying to crank screams low effective voltage. Dead battery, bad connection. That ground strap is one point I didn't see mentioned that would have been disturbed during an engine swap. An easy test is to stab a volt meter between the engine and chassis. Make sure you have good points on both, then have someone attempt to crank. The meter should not go over 0.1V while cranking... way less if it won't. You could also use a jumper cable to bridge from engine to chassis as a test. Again pick a good spot. The valve cover is NOT a good spot, as it's totally rubber isolated.

    But I think we should first wait on the young lady's artwork.


    /.randy

  16. #16
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    t5Umsli.jpg

    I excluded the ZKE/anti-theft part since unplugging it doesn't seem to cause a no-start condition (source: 2000 2.8L roady w/ alpine system).

  17. #17
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    Quote Originally Posted by LannVouivre
    I'm drawing the wiring diagram... It's specifically for the 97 1.9L manual; there's like a difference of 1 wire color and 6 or so pin locations between 96, 96, and 2.8L...
    Quote Originally Posted by LannVouivre
    So that's a complete electrical diagram for the 1.9 from EWS to starter, connected up from several different related diagrams? That took a lot of understanding and skill -- mechanics, electrical, and freehand drafting. Thanks.
    BMW MOA 696, BMW CCA 1405

  18. #18
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    Quote Originally Posted by Vintage42 View Post
    So that's a complete electrical diagram for the 1.9 from EWS to starter, connected up from several different related diagrams? That took a lot of understanding and skill -- mechanics, electrical, and freehand drafting. Thanks.
    Just the two diagrams. The only part that is a mystery is what the EWS does, because modules are really weird. The starter itself is really simple, because you just have a starter solenoid (windings) that closes the main circuit while also moving the pinion gear to the flywheel or flexplate to mesh via a lever/plunger. The plunger is pulled by the windings of the solenoid to allow the main circuit of the starter motor to close; one winding of the solenoid pulls, the other keeps the plunger held. The plunger is what closes the circuit probably? to prevent damage to the teeth of the flexplate/flywheel and starter pinion via early engagement.

    Anyway, the important thing is: power is supplied to the solenoid and the starter motor. Solenoid power is gated via the relays and crap; motor power is always hot but only can actually do anything when the solenoid completes its circuit with that plunger. Both of these systems are grounded by the starter body, which is grounded by the engine block, which is either grounded securely with (often multiple) ground straps to the chassis, or intermittently/poorly (insufficient for carrying massive starter motor amperage). Also maybe check the condition of the ground strap, perhaps, and the main power to the starter. I have seen corrosion get up under insulation before, although that was on a battery cable and not exactly hidden.

    What you could also do is verify that power is getting to the solenoid when the key is held in START with the clutch depressed or auto transmission in PARK, and verify that at least you have power reaching the main post of the starter motor at all times. Then you can make sure that the starter and block don't have much resistance, and then for too much resistance from the block to the chassis. I have also heard of (specifically on '85 Tercels, sorry) electrical issues when you have one ground connected, but not the one from the transmission or from the head. I don't have any idea what BMW does, but from Randy's comment, I'll wager you have at least one big fat block strap. If you wanted to overachieve and do the JDM technique of millions of grounds everywhere, you could put a ground strap on the head and transmission as well; I hear one guy did that and he got 600 mpg and also ended world hunger*.

    *Might help if you have a problem with good connections everywhere, since the powertrain/drivetrain are pretty much entirely insulated otherwise. I think Randy suggested a ground strap/jumper cable from the metal part of the block to a clean spot on the chassis. I'd probably clip on a bellhousing bolt and to a strut mount crown bolt.

  19. #19
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    @LannVouivre – Thank you so much for this – incredible! I wanted to give some quick updates:

    ~ Tried again to see if the problem was battery-related. Took the battery back to O'Reilly's and they tested and charged it and said it was good.
    ~ Checked engine ground near passenger-side motor mount, and it's secure.
    ~ Replaced the three fuses you suggested in the engine bay – #45, #44, and #28. #28 was missing on my car, and it seems like there's no metal "seat" for the fuse to fit. Installed a fuse anyway and no luck.
    ~ Replaced EWS Antenna, just to get rid of the whole "kill switch" possibility. Car still push-starts.

    Then, yesterday, after reading a forum I'd never seen before, I tried pushing down the clutch exactly straight. This was pretty tricky to do – I didn't realize how much slop was in the clutch pedal. Didn't work the first time, but it started up on the second try. Drove it around for a bit, turned it off, tried again, and it started a second time with more hesitation. Repeated the process a third time and the starter didn't engage. So I looked down at the clutch position sensor that @Vintage42 suggested and it looked pretty worn out. Tried pushing the switch itself all of the way in while starting the car (and hanging upside down in the process). This didn't work, but I'm more and more convinced that the problem was with the clutch position sensor, so I ordered one online. Hopefully, it should be delivered today – I'll let you know if it works!

    Either way, I can't thank you guys enough – without this forum and all the helpful people in it, I'd be sunk. From the bottom of my heart, thank you.

  20. #20
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    Man, this stuff is so frustrating sometimes. Took out the old clutch position sensor, installed a new one and still nothing but a click or two from the starter. After the second or third try, it doesn't even click anymore. I'm going to a friend's shop tomorrow – I can try out other things like using a wire brush to clean off the grounding cable between the motor mount and the car. I can also change out the alternator – I have a new one of those.

    Any other suggestions?

  21. #21
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    Ok, try this. With key in START (NOTE: key must be in START for every test except for ground continuity and F31's red/yellow wire to EWS II 5), check for power at green/black pin 3 to EWS II. If power is there, next check at black/yellow pin 1, EWS II. If no power is at green/black pin 3 EWS II, check for power at IGN switch pin 4 black/yellow. If there is no power at pin 4 IGN black/yellow, your ignition switch is inoperational.

    If there is no power at black/yellow pin 1 EWS II, check red/yellow 5 and brown/black 9. If power is there, check brown 7 to chassis ground for low resistance/continuity, as that's your ground wire. If no power is there, voltage is stopping at F31 or F45, the starter immobilizer switch (clutch probably), or in between. If F31 or F45 is blowing over and over, then you have a short in the circuit that needs repaired. You will want to check from the ground side (power side has voltage at all times for F31 or in ACC, RUN, and START for F45: choose the opposite pin) to the chassis for continuity. This will be the short to ground preventing you from starting. If the fuses are not blowing, then you need to see if power is reaching the clutch position sensor (pin 3 violet/white, if the ground has continuity (pin 1 brown) to chassis, and if pin 2 blue/black has continuity to pin 9 brown/black EWS II.

    If all wires to EWS II have continuity and power when they should, but the black/yellow EWS II 1 wire doesn't get power in START, the EWS II is faulty*; blk/yel 1 gets power in START, next check must be the starter black/yellow needs power in START, red needs 12v always, and the starter casing via both the solenoid shell and the motor shell must have solid continuity to chassis. Lastly, you have a black/green wire from the starter to the body CTRL module behind the glovebox (pin 12); I have NFI what it does. I think it's just a signal, but I would check for continuity to the BCM from the starter because it's supposed to receive voltage when the solenoid allows the starter motor to operate and this might actually be supposed to do something relevant.

    Get a digital multimeter and check this stuff, they're like $14 and if you don't test the circuit you're just bashing your face into a wall doing things that are a pain and possibly a waste of time.

    By the way, turns out F28 is for the auto transmission and EGS is for electric gearshift or something.

    *I don't know if the brown wire pin 7 EWS II is supposed to receive power at any time, or if it's just for voltage leakage or something.
    Last edited by LannVouivre; 02-17-2017 at 02:12 AM.

  22. #22
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    Quote Originally Posted by forestcasey View Post
    Man, this stuff is so frustrating sometimes. Took out the old clutch position sensor, installed a new one and still nothing but a click or two from the starter. After the second or third try, it doesn't even click anymore. I'm going to a friend's shop tomorrow – I can try out other things like using a wire brush to clean off the grounding cable between the motor mount and the car. I can also change out the alternator – I have a new one of those.

    Any other suggestions?

    Did you ever resolve this problem? I'm experiencing similar problems with my Z3.

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    fascinating and following

  24. #24
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    I need wiring diagram for 2000 bmw z3 2.3 2.5L My cars ignition won't shut off unless I disconnect the battery, I pulled the red ignition switch on back of tumbler to ensure it was in the off position (did nothing), I replaced the ignition switch (did nothing), when connecting power to battery, fuel pump primes itself and cluster comes on, I put key in ignition and turn the new ignition switch to start engine and nothing happens.. -replaced starter -replaced ignition switch -replaced clutch sensor -checked most of the harness for shorts or corroded wires -checked many of my connections as far as cluster/ignition/dme/ews/other electronic systems on passenger side behind glove box

    - - - Updated - - -

    I need wiring diagram for 2000 bmw z3 2.3 2.5L My cars ignition won't shut off unless I disconnect the battery, I pulled the red ignition switch on back of tumbler to ensure it was in the off position (did nothing), I replaced the ignition switch (did nothing), when connecting power to battery, fuel pump primes itself and cluster comes on, I put key in ignition and turn the new ignition switch to start engine and nothing happens.. -replaced starter -replaced ignition switch -replaced clutch sensor -checked most of the harness for shorts or corroded wires -checked many of my connections as far as cluster/ignition/dme/ews/other electronic systems on passenger side behind glove box

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