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Zainwq 
Newbie
Joined: 16-October-2005
Location: Qureshi
Status: Offline
Points: 28
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 Topic: E30 M3 Starting Issues
Posted: 12-February-2006 at 14:52 |
I have an annoying intermittent starting issue. It turned fine but didnt spark a couple of weeks ago, so I deduced it was the coil. I then bought a new one. Upon fitting, started on first turn. This weekend, went to start, same problem. It turns fine, I can smell petrol so Im guessing no fuel issues, so must be sparky related. I flattened the battery trying, so left it. Few hours later, tried jumping it and it started first time. So i put the battery on charge overnight, and sorted, starts on the button. Could a weak battery be the cause? Dash lights look strong, was enough (or so I think) cranking power, so it is just coincidence it started first time with a jump start? Where are the starter relays on this? Im gonna change them anyhow to be safe. With the old coil there was power going to it (dont know how much though), would a knackered starter relay not have cut off the power to the coil?
Its a 1990 215bhp M3.
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Matt T
Really Senior Member I
Joined: 16-January-2006
Location: London
Status: Offline
Points: 399
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Posted: 12-February-2006 at 22:01 |
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If you had power for the electrics then i doubt there would be a battery issue with the spark, especially as there was enough power to crank it over.
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Karlp
Really Senior Member I
Joined: 21-March-2004
Location: United Kingdom
Status: Offline
Points: 354
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Posted: 13-February-2006 at 03:19 |
I could be the battery. I have had this problem on many a car and motorbike.
If the battery is down then the cranking takes all the available juice and leaves nothing for the coils etc.
Karl
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UweM3
Moderator Group
Joined: 11-February-2003
Location: United Kingdom
Status: Offline
Points: 5445
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Posted: 13-February-2006 at 03:28 |
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When it doesn't start next time, don't change anything but swap your ECU with your brother's.
My car starts even when the battery is juuust able to crank it after parking for two weeks. BTW my battery is 8 years old.
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E61 520d, slow and buzzy but my wallet likes the mpg.....
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Adrian H
Senior Member II
Joined: 06-May-2004
Location: The Toon
Status: Offline
Points: 210
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Posted: 13-February-2006 at 04:10 |
The battery is still a possibility. I had a similar problem with mine, would crank over but would not fire and after I put the battery on charge for approx twelve hours it would fire first turn of the key.
My car does sit in the garage for long periods of time so I bought a battery conditioner which is now connected all the time and since then the car has started everytime without fail.
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UweM3
Moderator Group
Joined: 11-February-2003
Location: United Kingdom
Status: Offline
Points: 5445
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Posted: 13-February-2006 at 04:46 |
 Adrian H wrote:
The battery is still a possibility. I had a similar problem with mine, would crank over but would not fire and after I put the battery on charge for approx twelve hours it would fire first turn of the key.
My car does sit in the garage for long periods of time so I bought a battery conditioner which is now connected all the time and since then the car has started everytime without fail. |
If he hasn't got spark, charging the battery won't help. But I hope he has checked for no spark and not assumed it.
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E61 520d, slow and buzzy but my wallet likes the mpg.....
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Adrian H
Senior Member II
Joined: 06-May-2004
Location: The Toon
Status: Offline
Points: 210
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Posted: 13-February-2006 at 05:02 |
UweM3 wrote:
Adrian H wrote:
The battery is still a possibility. I had a similar problem with mine, would crank over but would not fire and after I put the battery on charge for approx twelve hours it would fire first turn of the key.
My car does sit in the garage for long periods of time so I bought a battery conditioner which is now connected all the time and since then the car has started everytime without fail.
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If he hasn't got spark, charging the battery won't help. But I hope he has checked for no spark and not assumed it. |
Uwe, the reason I mentioned my experience, was he said that it started after an overnight charge.
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UweM3
Moderator Group
Joined: 11-February-2003
Location: United Kingdom
Status: Offline
Points: 5445
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Posted: 13-February-2006 at 05:26 |
Adrian H wrote:
UweM3 wrote:
Adrian H wrote:
The battery is still a possibility. I had a similar problem with mine, would crank over but would not fire and after I put the battery on charge for approx twelve hours it would fire first turn of the key.
My car does sit in the garage for long periods of time so I bought a battery conditioner which is now connected all the time and since then the car has started everytime without fail.
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If he hasn't got spark, charging the battery won't help. But I hope he has checked for no spark and not assumed it. |
Uwe, the reason I mentioned my experience, was he said that it started after an overnight charge. |
Adrian, didn't question your experience 
My no spark problem was cause by the ECU. One day fine, the other day 
I re-soldered a few bits on the PCB and works fine since.
(found the right one's by accident while fiddling around with the PCB --> engine suddenly stalled)
This ECU is currently powering another M3 with some stalling issues. Works fine one day, and next day keeps stalling. Swapped ECU's and car runs fine.
Personally I don't think a "bad" battery is responsible for the car not starting. As long it cranks over with decent speed, it should start if everything else is fine.
It might look like the battery was the culprit when you swap for a new one and the car immediately starts, but you may have some "lazy" circuits (corrosion!!) in your ECU or somewhere else.
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E61 520d, slow and buzzy but my wallet likes the mpg.....
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Jake
Groupie
Joined: 19-February-2005
Location: East Anglia
Status: Offline
Points: 82
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Posted: 13-February-2006 at 05:54 |
I'd swap in another main relay. This one is under the black plastic panel behind the coolant tank.
HTH,
Jake
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Zainwq
Newbie
Joined: 16-October-2005
Location: Qureshi
Status: Offline
Points: 28
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Posted: 13-February-2006 at 06:25 |
There defs wasnt a spark on the old coil uwe, but there WAS power going to it. Would a knackered starter relay still give the coil power? I remember ringing Simon at C3, and he said it would. Judging by the replies, it could be:
1 - Battery didnt have enough juice.
2 - Loose solder on ECU
3 - Starter Relay
Uwe, my brother wont let me swap ECU's, trust me! Im inkling on the starter relay. Would I be right? If it was a loose solder, wouldnt it just happen all the time? Including whilst driving? Its perfect once im moving.
This relay is behind the black plastic cowling under the scuttle/windscreen area next to the header tank?
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rezaq
Senior Member II
Joined: 20-March-2003
Location: United Kingdom
Status: Offline
Points: 248
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Posted: 13-February-2006 at 06:27 |
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Interesting read. No way am I putting my ECU on his car though!! Sorry Zain.
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UweM3
Moderator Group
Joined: 11-February-2003
Location: United Kingdom
Status: Offline
Points: 5445
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Posted: 13-February-2006 at 06:47 |
rezaq wrote:
Interesting read. No way am I putting my ECU on his car though!! Sorry Zain. |
bit harsh IMHO . I have just given my spare ECU to somebody round the corner I don't even know the surname...
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E61 520d, slow and buzzy but my wallet likes the mpg.....
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UweM3
Moderator Group
Joined: 11-February-2003
Location: United Kingdom
Status: Offline
Points: 5445
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Posted: 13-February-2006 at 06:54 |
Zainwq wrote:
There defs wasnt a spark on the old coil uwe, but there WAS power going to it. Would a knackered starter relay still give the coil power? I remember ringing Simon at C3, and he said it would. Judging by the replies, it could be:
1 - Battery didnt have enough juice.
2 - Loose solder on ECU
3 - Starter Relay
Uwe, my brother wont let me swap ECU's, trust me! Im inkling on the starter relay. Would I be right? If it was a loose solder, wouldnt it just happen all the time? Including whilst driving? Its perfect once im moving.
This relay is behind the black plastic cowling under the scuttle/windscreen area next to the header tank? |
I might be wrong, but from looking at your sig it's a 90 car. There is a slight difference between the engine wiring loom.
On older cars (like mine) the coil is fed by the relais behind the header tank (big green wire) but on cars post 88 this green wire is running from th emain harness connector.
So this means your coil will see 12V even if the relais is knackered.
But when you talk abaout "starter relais" which one you refering to?
You have got two relais behind the coolant tank.
--main ECU relais
--fuel pum relais
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E61 520d, slow and buzzy but my wallet likes the mpg.....
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Zainwq
Newbie
Joined: 16-October-2005
Location: Qureshi
Status: Offline
Points: 28
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Posted: 13-February-2006 at 07:55 |
Yes, its a 1990 215bhp M Uwe.
I dont know a lot about the starter relays, its just something ive heard. So what exactly is the starter relay?? If I am getting a live feed permanently, then what does the relay do? I do recall that someone said that even if the relay was knackered that the coil would still see power. Shall I change them all and see if it happens again?
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LateM3
Newbie
Joined: 13-February-2006
Location: U.K.
Status: Offline
Points: 5
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Posted: 13-February-2006 at 08:39 |
Uwe wrote: bit harsh IMHO  . I have just given my spare ECU to somebody round the corner I don't even know the surname...
Thats me dude!!!! Just wanted to say thanks for the help, I have a replacement now so I'll return yours whenever ya want. A very genourous deed from a true inthusiast.
P.S. I changed all the cheap bits first to no avail, blue choke switch, relays, cap n rotor, fuel filter, plugs, swapped the ecu and no problems since  . Be sure to keep all the old parts, theyre good for spares especially as it turns out nothing was wrong with mine.
Big shout to Jake :met you at Uwe's a few sundays ago.
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Jake
Groupie
Joined: 19-February-2005
Location: East Anglia
Status: Offline
Points: 82
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Posted: 13-February-2006 at 10:26 |
LateM3 wrote:
Big shout to Jake :met you at Uwe's a few sundays ago. |
A big shout backatcha mate!
Zainwq,
If it will turn over its not the starter relays. BTW, these are found in the fuse box (K5 and K7). If you smelled fuel while starting then its not likely your fuel pump relay. Therefore, I would focus on the main relay.
Hope this helps,
Jake
P.S. Uwe, I'm picking up the spacers this week! I'll have a set in the mail to you by Friday.
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E30 M3 Starting Issues