Can’t get my E30 M3 started at all
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Category: Technical & Model Specific Forums
Forum Name: BMW ///M Power
Forum Discription: Ask your BMW M Power Technical Questions here (M1, M2 hybrids, M3, M5 & M6)
URL: http://www.bavarian-board.co.uk/forum_posts.asp?TID=12126
Printed Date: 03-May-2024 at 05:52
Topic: Can’t get my E30 M3 started at all
Posted By: andyb
Subject: Can’t get my E30 M3 started at all
Date Posted: 22-November-2004 at 10:28
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Posted this already on S14.net but wondered if anyone here could help?
Car was running fine, but fuel was in the red, no warning light though. I pulled out of a junction and it stalled, then it wouldn’t restart. I went and stuck 5l of fuel in still wouldn’t start. I pushed it the 1/2 mile home and got it towed up my road, put the battery on charge overnight. I reconnected the battery and tried to start it while spraying an ether based starter spray into the plenum, still nothing at all. Car cranks over but does not fire. Since the car should at least try and fire on the ether even if it's getting no fuel I figured it's ignition related. Checked for a spark on the plugs, nothing (They were really sooty too) Checked for 12V at the coil, that's there. Then shorted the coil LT side to get it to fire independent of the ignition, using the coil lead to ground you get a very weak spark. I proved the coil was okay in the end by using a switch to get it to fire on the bench. The resistance on the secondary coil was actually 5.7k the autorange had me fooled for a bit! Following the troubleshooting guide I found on S14.net I've found that there is no ground signal from the ECU the resistance measured between ground and pin #1 is about 42 Meg ohms and stays the same as you try and crank the car over. I also put a timing light on the coil to see if the EMF in the coil was being generated. It worked fine on the bench but not on the car. Now I have the ECU apart it looks visually okay no burnt transistors or anything. I could really do with a known to be working ECU just to prove that is the problem. If any UK guys have a spare on I could borrow to try I would be very grateful. Many Thanks Andy |
Replies:
Posted By: DAWIEM3
Date Posted: 22-November-2004 at 17:05
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Andy, I have a spare ECU`s. Send me a PM with your contact number and we will see what we can do to help. Where in the country are you. ------------- E30 M3 Road car ( Now in Hongkong ) E30 M3 Track Car S14 2.0L 2002 in progress E30 C2 2.7 Alpina E36 M3 3.2 EVO |
Posted By: Mags
Date Posted: 22-November-2004 at 17:21
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Dunno if this could be helpful but I was having some intermittant problems a while ago, the car would just cut out and sometimes fail to re-start. Seems E30's have two relays behind the cover at the bottom of the windscreen, Fuel pump and DME, they can easily fail with age, they don't cost much to replace. I don't know what the affect of the DME relay would be if it failed though? Mags ------------- '58 Austin Healey Sprite '72 VW Camper '95 BMW 540i Touring '02 Suzuki SV650S |
Posted By: andyb
Date Posted: 23-November-2004 at 02:26
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Which one is the DME relay?
I had someone check the three relays behind the expansion tank while I turned the car over, He seemed to think only one from the three was switching, not sure if this is correct or not though? |
Posted By: Nick
Date Posted: 23-November-2004 at 04:13
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No.. that's the fuse box.. we are talking behind the long plastic cover below the windscreen. Perhaps, if like me you were unaware that it ever came off.. I thought it was the wiring loom in there. Anyway, open the bonnet and look at the plastic shroud just below where the vin number is etched onto the scuttle.
.. trouble is, I still don't know what the gizmo's do.. I do know however that sometimes you can get a dead car to start just by wiggling them! ------------- |
Posted By: kevin
Date Posted: 23-November-2004 at 05:24
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There are three relays tucked away under there.
Starting from the outside of the car they are Evaporative Purge Relay Main Relay Fuel Pump & O2 sensor Heater Relay ------------- Kevin '04 E46 330Ci Convertible '08 E61 535d Touring (TorqueMeister Towbarge) ’95 E34 M5 ’89 E30 M3 (Cecotto) |
Posted By: Nick
Date Posted: 23-November-2004 at 06:45
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Kev, you are indeed becoming the font of all E30 M3 knowledge. ------------- |
Posted By: kevin
Date Posted: 23-November-2004 at 07:00
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Nick,
I don't think so, there are a lot of people on here who have forgotten more than I know. ------------- Kevin '04 E46 330Ci Convertible '08 E61 535d Touring (TorqueMeister Towbarge) ’95 E34 M5 ’89 E30 M3 (Cecotto) |
Posted By: Nick
Date Posted: 23-November-2004 at 07:46
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yes, but not all of them are always on-line. 2.5k posts in two years is no mean feat. ------------- |
Posted By: andyb
Date Posted: 23-November-2004 at 10:25
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Yep those are definitely the ones I checked, as you have to lift the coolant expansion tank up to get the cover off, my fuse box is on the other side of the engine bay (RHS as you look at the car).
DAWIEM3 has very kindly agreed to try my ECU in his car so hopefully I'll know if it is that or not on Friday 
Cheers for the info about those relay's sounds like my Main relay is clicking on okay then. Will let you all know how it turns out |
Posted By: Rags
Date Posted: 23-November-2004 at 11:13
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didn't bother reading the replies, but is your fuel pump priming(/buzzing)? As this is sure sign of no firing.
Rags ------------- 
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Posted By: andyb
Date Posted: 01-December-2004 at 11:12
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After much head scratching I'm starting to get somewhere.
My main relay was clicking so I foolishly assumed it was working and it was sort of.... The relay is switching okay but the supply that it is supposed to switch is not there. I've traced it back a bit to the 'Battery Terminal block' this is located on the bulkhead just to the RHS of the three relays (Main, Fuel and Purge) as you look at the car. It has 12V on all of the RHS connections but 0V on all the LHS connections, one of these LHS wires is supposed to be the 12V that the relay switches for the ECU (Hence no spark at the mo). Does anyone know if these terminal blocks have an internal fuse or something? The supply I've lost comes into the relay on pin 30 according to the ETM and is supposed to be 12V all the time. The other thing I've found is one of the other relay contacts has gone to earth, pin 87 I think so this could have caused the supply to fail but I need to go back through the wiring to find exactly where the short is, it's somewhere in the loom that goes to the injectors. wish me luck! |
Posted By: andyb
Date Posted: 06-December-2004 at 07:15
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Finally got it running again, learnt lots into the bargain too!
Turned out to be one of the main 12V supply cables (the smaller of the two) from the battery to the engine bay had broken somewhere internally. This meant that although my main relay was clicking on and off there was no supply for it to switch, I've not pulled the old cable out to find where it broke but have run a temporary replacement in (with inline fuse!!) which started the car fine first time. This was after I thought I had a bad coil / ECU so I'm pretty happy that it's a cheap fix ! Thanks for you 're help guys Andy Moral of the story, if you can't start you're car because you have no spark check the battery connector block both sides for 12V!!!! Dave Thanks so much for the loan I'll get it back to you ASAP |
Posted By: DAWIEM3
Date Posted: 06-December-2004 at 12:50
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Andy, No Problem. Give the ECU to Uwe and I will collect it off him. Glad you managed to get her running again, and bonus you have learnt loads to share with us all, and have the satisfaction that you fixed it by yourself. Regards Dave ------------- E30 M3 Road car ( Now in Hongkong ) E30 M3 Track Car S14 2.0L 2002 in progress E30 C2 2.7 Alpina E36 M3 3.2 EVO |
Posted By: UweM3
Date Posted: 05-January-2005 at 13:41
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BINGO!
this time it's me with the non starting car! No spark like Andy's. Dave have you actually tried the ECU you gave to Andy? Just to be sure not to shoot into the dark before I pull everything to pieces. I will start with the 12V supply Andy described. Hopefully I will be as lucky as he was. ------------- E61 520d, slow and buzzy but my wallet likes the mpg..... |
Posted By: DAWIEM3
Date Posted: 05-January-2005 at 18:35
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Uwe, I tried both Andy`s ECU in the white Road car and the ECU I lent Andy which you now have. Both of them worked. I have another spare available if you are suspecting the ECU`s. Have you tried my ECU ?. I take it you definately have checked for spark, hence suspecting the ECU. Give me a call tomorrow, as I up to Bruntings on Friday and could pop the other Ecu off to you, or stop on the way back and you can try your ECU in the road car. Your call. Cheers,
Dave. ------------- E30 M3 Road car ( Now in Hongkong ) E30 M3 Track Car S14 2.0L 2002 in progress E30 C2 2.7 Alpina E36 M3 3.2 EVO |
Posted By: UweM3
Date Posted: 06-January-2005 at 04:42
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Dave,
I have tried ECU but still no spark. I will have a more in depth search tonight. Have fun tomorrow. Uwe ------------- E61 520d, slow and buzzy but my wallet likes the mpg..... |
Posted By: andyclient
Date Posted: 06-January-2005 at 10:24
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Don't know if this is any help but , looking through the history on my car it had a non starting prob which turned out to be I Quote "Locate shorted crankshaft main sensor & faulty ecu speed sensor,replace as req. Remove suspect ecu assembly for testing (ecu HT circuit found to be damaged due to failed crankshaft speed sensor) " Had a similar prob on my previous Hartge 325 a mechanic friend suggested the crankshaft speed sensor, but on that occassion it was the ecu so i assume they are connected, I see you have changed the ecu, so could it maybe be the sensors ?? ------------- 
01 E46 320d Touring 88 E30 M3 Sadly Gone 93 E36 325 TD Gone but still going 87 E30 Hartge 325 (gone but not forgotten) |
Posted By: UweM3
Date Posted: 06-January-2005 at 11:34
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Thanks but sensors are both new (June 04) and I have a working spare ECU from DawieM3 to make sure it will start if the rest is ok. ------------- E61 520d, slow and buzzy but my wallet likes the mpg..... |
Posted By: UweM3
Date Posted: 06-January-2005 at 13:59
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I have checked my main relay and it doesn't click.
the power Andy described is present at pin 30, but the "trigger" pin is dead when ignition is on. I will have to wait till Saturday and follow the wires from start to end to see if there is any shortage. I have shortened the main relay but still no spark. The ICV is humming but that's it. Dizzy and rotor are fine and the coil is sseing 12V on both ends. I am not quite sure if it is sufficient just to hold the spark plug against the rocker cover nut to get ground, but thought that is ok. Can anyone confirm this? ------------- E61 520d, slow and buzzy but my wallet likes the mpg..... |
Posted By: UweM3
Date Posted: 06-January-2005 at 15:38
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Have the car running now. I have plugged a wire in pin 15 of the coil and use this to trigger the ECU relay.
Car started immediatley, but no rev counter. So I will have to trace the wire back and see where it looses the power. ------------- E61 520d, slow and buzzy but my wallet likes the mpg..... |
Posted By: DAWIEM3
Date Posted: 06-January-2005 at 19:12
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Uwe,
Glad you have got the car running again. You don`t think that this is a re - occurance of when it stopped before, and with moving things about made you suspect the Ecu. Intermittent faults are the worst. At least you know it is not too major.
Cheers,
Dave. ------------- E30 M3 Road car ( Now in Hongkong ) E30 M3 Track Car S14 2.0L 2002 in progress E30 C2 2.7 Alpina E36 M3 3.2 EVO |
Posted By: UweM3
Date Posted: 07-January-2005 at 04:25
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Dave,
last time it didn't start the ECU was full of water 
I will have to trace the wires now to see what is causing it. At least is shows that my ECU is still ok  ------------- E61 520d, slow and buzzy but my wallet likes the mpg..... |