Mystery Problem With 940

Mar 1st, 2006, 20:01

is there any one out there who can shed some light on what's going on with my 1991 940 2ltr estate. It was driving perfectly until it started making a funny noise almost as if one of the belt,s was coming off, shortly followed by losing the radio, indicator's and lights. The noise got gradually got loader and there was a smell of burning coming from the engine. Pulled over and switched off, checked all belts and fuses, all ok, but would'nt start. After leaving it for about 20 mins it started up and drove home as if nothing had happened(although indicator's etc still did'nt work) Got home and car refused to start, so got local garage to come out, car would'nt jump start but managed to bump start it and got it to garage where they reckened the starter motor had fried so replaced it. Picked it up todayand everything seemed as good as new, drove for about an hour, stopped at supermarket, started her up and the noise was back! It seam's after all that i'm back to square one and no-one seem's to have the slightest idea of what is going on! Can anyone help?

Mar 1st, 2006, 20:14

Hi there i saw your post about your 940 it sounds like it could be the ignition switch not returning correctly so is jamming on the starter motor also as you had no indicators it does point to the same thing .
If you get it to do it again try moving the key in the ignition barrel but at the same trying to leave the car running .

Russ

Mar 1st, 2006, 21:18

Thanks for that, will try that, but would this be a reason for the burning? as there was definately smoke coming from the engine when i got home. Could it be a wire shorting out? also what do u think could b causing the noise as this seems to happen before anything else? I know this is asking alot but i really am stuck for idea's and any help at all is greatly appriciated!

bogart · Mar 1st, 2006, 23:57

Definitely starter motor not disengaging or being re-engaged with engine running, neither do it much good. As it has happened again so soon assume starter okay, they did actually replace it didn't they not just tell you they had. If so leaves the problem of it re-engaging which can only be caused by wiring fault, intermittent short or as previously stated possible ignition switch fault.
Regards

LankyTim · Mar 2nd, 2006, 18:19

sticking solenoid on starter, starter cant disengage and gets red hot, perhaps it affects the battery causing the electrical probs.

bogart · Mar 2nd, 2006, 19:49

If starter doesn't disengage it frys and electrics such as mentioned, indicators, windows etc fail to operate. Can you still start the car? if so does it make noise on starting?
Cheers

LankyTim · Mar 4th, 2006, 11:02

Ive seen similar problems on lorries, the starter somehow "backfeeds" into the battery and kills the electrics, sometimes blowing up the battery. Maybe the starter acts like a generator, as its being turned by the engine. Thats the only explanation I can think of though it sounds a bit far fetched!

Ian M · Mar 4th, 2006, 18:03

This problem I have an answer for as it happend to me. what you have is a sticking ignition switch. Any of you can get the noise by turning the starter motor over with the engine running although I wouldnt recomend it. The reason that some electrical circuits dont work is that they are switched off when the ignition key is in the start position . To Save power. On mine I had to just toutch the bottom of the key to make it return to the run position and everything worked fine. I fixed it completley by ungumming the ignition switch with WD40.

Mar 5th, 2006, 19:06

Hi there everyone, thanks to everyone for your suggestions about my problem, i have since changed the ignition switch and have since done 200 miles without a problem, so it looks like the mystery is solved!!!

ALANEDWIN · Mar 6th, 2006, 15:46

I had exactly the same thing with my old 740. The ignition switch was not returning after start up and the starter motor was running. I was always able to spot it because the radio/instruments did not work. Unfortunately one day my wife had the car and didn't notice that nothing was working!! Eventually the starter caught fire on the M6 and stranded her and 4 friends, but of course it was my fault. I found that DW40 regularly applied stopped it happening.

Alan Wilson

740gl
960 3.0
940 cd
all estates of course

Mar 1st, 2006, 20:01	#1
JOEYBIRD Guest Location:	Mystery Problem With 940 is there any one out there who can shed some light on what's going on with my 1991 940 2ltr estate. It was driving perfectly until it started making a funny noise almost as if one of the belt,s was coming off, shortly followed by losing the radio, indicator's and lights. The noise got gradually got loader and there was a smell of burning coming from the engine. Pulled over and switched off, checked all belts and fuses, all ok, but would'nt start. After leaving it for about 20 mins it started up and drove home as if nothing had happened(although indicator's etc still did'nt work) Got home and car refused to start, so got local garage to come out, car would'nt jump start but managed to bump start it and got it to garage where they reckened the starter motor had fried so replaced it. Picked it up todayand everything seemed as good as new, drove for about an hour, stopped at supermarket, started her up and the noise was back! It seam's after all that i'm back to square one and no-one seem's to have the slightest idea of what is going on! Can anyone help?

Mar 1st, 2006, 21:18	#3
JOEYBIRD Guest Location:	burning smell Thanks for that, will try that, but would this be a reason for the burning? as there was definately smoke coming from the engine when i got home. Could it be a wire shorting out? also what do u think could b causing the noise as this seems to happen before anything else? I know this is asking alot but i really am stuck for idea's and any help at all is greatly appriciated!

Mar 5th, 2006, 19:06	#9
JOEYBIRD Guest Location:	Mystery Solved!! Hi there everyone, thanks to everyone for your suggestions about my problem, i have since changed the ignition switch and have since done 200 miles without a problem, so it looks like the mystery is solved!!!

Mar 1st, 2006, 20:14	#2
Russell@ RT Mechanics Guest Location:	Hi there i saw your post about your 940 it sounds like it could be the ignition switch not returning correctly so is jamming on the starter motor also as you had no indicators it does point to the same thing . If you get it to do it again try moving the key in the ignition barrel but at the same trying to leave the car running . Russ

Mar 1st, 2006, 23:57	#4
bogart Master Member Last Online: Jan 31st, 2023 09:51 Join Date: Nov 2003 Location: Languedoc Roussillion	Definitely starter motor not disengaging or being re-engaged with engine running, neither do it much good. As it has happened again so soon assume starter okay, they did actually replace it didn't they not just tell you they had. If so leaves the problem of it re-engaging which can only be caused by wiring fault, intermittent short or as previously stated possible ignition switch fault. Regards

Mar 2nd, 2006, 18:19	#5
LankyTim Missing the point Last Online: Today 22:41 Join Date: Nov 2001 Location: Stoke-On-Trent View Photos By: LankyTim	sticking solenoid on starter, starter cant disengage and gets red hot, perhaps it affects the battery causing the electrical probs.

Mar 2nd, 2006, 19:49	#6
bogart Master Member Last Online: Jan 31st, 2023 09:51 Join Date: Nov 2003 Location: Languedoc Roussillion	If starter doesn't disengage it frys and electrics such as mentioned, indicators, windows etc fail to operate. Can you still start the car? if so does it make noise on starting? Cheers

Mar 4th, 2006, 11:02	#7
LankyTim Missing the point Last Online: Today 22:41 Join Date: Nov 2001 Location: Stoke-On-Trent View Photos By: LankyTim	Ive seen similar problems on lorries, the starter somehow "backfeeds" into the battery and kills the electrics, sometimes blowing up the battery. Maybe the starter acts like a generator, as its being turned by the engine. Thats the only explanation I can think of though it sounds a bit far fetched!

Mar 4th, 2006, 18:03	#8
Ian M New Member Last Online: Nov 21st, 2008 21:02 Join Date: Jan 2006 Location: Dorking	This problem I have an answer for as it happend to me. what you have is a sticking ignition switch. Any of you can get the noise by turning the starter motor over with the engine running although I wouldnt recomend it. The reason that some electrical circuits dont work is that they are switched off when the ignition key is in the start position . To Save power. On mine I had to just toutch the bottom of the key to make it return to the run position and everything worked fine. I fixed it completley by ungumming the ignition switch with WD40.

Mar 6th, 2006, 15:46	#10
ALANEDWIN New Member Last Online: Nov 6th, 2007 10:49 Join Date: Nov 2002 Location: LIVERPOOL	I had exactly the same thing with my old 740. The ignition switch was not returning after start up and the starter motor was running. I was always able to spot it because the radio/instruments did not work. Unfortunately one day my wife had the car and didn't notice that nothing was working!! Eventually the starter caught fire on the M6 and stranded her and 4 friends, but of course it was my fault. I found that DW40 regularly applied stopped it happening. Alan Wilson 740gl 960 3.0 940 cd all estates of course

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)