S500 Engine cut off when hot [W140] - MBClub UK

hellgrace5 · 30-08-2010, 03:00 AM

Hello,

I have this W140 S500 WDB1400512A197157 engine cut off when hot. So far what I replaced were:

1, Crankshaft sensor
2, Camshaft sensor
3, Fuel pump x2
4, Fuel filter
5,Temp sensor (single connection)
6, Distributor cap x2
7, Distributor rotor x2
8, Electronic throttle valve ( MOST EXPENSIVE )
9, Fuel pump relay
10, HT cables x 10 (including 2 coil cable)
11, Spark plugs x8

What I have NOT replace
1, Coils x 2
2, Ignition control unit
3, ECU
4,MAF sensor

Any solution or did i miss check something ? Any advice ?

Thanks.

stwat · 30-08-2010, 03:15 AM

You need to get it on a star diagnostic machine. Im sure you would have saved a hell of a lot of money if you had done in the first place

hellgrace5 · 30-08-2010, 03:45 AM

I did get on diagnostic scan but there are only ASR faults. ASR light was on and i solved it by replacing the electronic throttle valve. Now no more ASR light.

Engine cut off when hot is stil there.

grober · 30-08-2010, 09:18 AM

Because its a V8 with 2 distributors and 2 coils it would be unusual for both high tension supplies coil/distributor/rotor arm/leads plugs to fail simultaneously so some cylinders should fire. I guess you need to look for a " global" failure which effects the complete engine. Does it just cut out suddenly or missfire for a while before stopping? A quick test for the ignition control unit [ I assume there's just one? the v12 has 2 I believe?] would be to get an electronic component freezer aerosol Freezer Spray : Freezer Sprays : Maplin and give it a quick "chill" --- If this restores function you may have your answer

hellgrace5 · 30-08-2010, 10:35 AM

Yes it has only 1 ignition module. Before it cuts off there is always an erratic idling situation like rpm is not steady then cut off.

What you mean is to spray some "chill" to lower down the ignition module temperature when its hot and unable to start ?

Will keep on update. Thanks!

**BlackC55** · 30-08-2010, 10:49 AM

This sounds like a classic ignition module fault.

hellgrace5 · 30-08-2010, 11:01 AM

The module cost is way too expensive. Oh my.. Hopefully its not the ignition module.

**BlackC55** · 30-08-2010, 11:04 AM

Get a second hand one or see if BBA Reman can repair it.

grober · 30-08-2010, 11:29 AM

Quote:

Originally Posted by hellgrace5

The module cost is way too expensive. Oh my.. Hopefully its not the ignition module.

That's why I suggested the "test" since substitution is not really an option with this high cost item. Not saying it will work but may help pinpoint your problem for little initial expenditure.
What happens is the heat sink compound between the unit and wing dries out. It then can't conduct heat away from the unit and it overheats and eventually fails. Temporary cooling down may restore function for a short time till it heats up again.

hellgrace5 · 30-08-2010, 11:33 AM

So do you suggest I open up the unit and chill it inside or just spray the outer part only ?

Thanks.

grober · 30-08-2010, 11:34 AM

THIS IS AN EXCELLENT SITE FOR YOUR MODEL K6JRF Auto Page

grober · 30-08-2010, 11:39 AM

Quote:

Originally Posted by hellgrace5

So do you suggest I open up the unit and chill it inside or just spray the outer part only ?

Thanks.

Just spray the outer surface externally in situ with lots of freezer.

Shane10010 · 16-11-2011, 11:02 AM

Anyone know if this helped isolate the problem?

30-08-2010, 03:00 AM	#1
hellgrace5 Member Join Date: Aug 2010 Posts: 33	S500 Engine cut off when hot [W140] Hello, I have this W140 S500 WDB1400512A197157 engine cut off when hot. So far what I replaced were: 1, Crankshaft sensor 2, Camshaft sensor 3, Fuel pump x2 4, Fuel filter 5,Temp sensor (single connection) 6, Distributor cap x2 7, Distributor rotor x2 8, Electronic throttle valve ( MOST EXPENSIVE ) 9, Fuel pump relay 10, HT cables x 10 (including 2 coil cable) 11, Spark plugs x8 What I have NOT replace 1, Coils x 2 2, Ignition control unit 3, ECU 4,MAF sensor Any solution or did i miss check something ? Any advice ? Thanks.

30-08-2010, 10:49 AM	#6
BlackC55 Authorised Forum Sponsor Join Date: Feb 2007 Location: Horndean, Portsmouth, Hampshire, Southsea Car: C43 AMG with mods, CLK55, C250TD, MK1 Caddy Posts: 14,166	This sounds like a classic ignition module fault. __________________ Olly Prestige car Service: I am listed here on MBClub please click to see services and discounts available.

30-08-2010, 11:04 AM	#8
BlackC55 Authorised Forum Sponsor Join Date: Feb 2007 Location: Horndean, Portsmouth, Hampshire, Southsea Car: C43 AMG with mods, CLK55, C250TD, MK1 Caddy Posts: 14,166	Get a second hand one or see if BBA Reman can repair it. __________________ Olly Prestige car Service: I am listed here on MBClub please click to see services and discounts available.

30-08-2010, 03:15 AM	#2
stwat Hardcore MB Enthusiast Join Date: Jun 2004 Location: Sheffield Car: 1989 W126 300 SE Posts: 1,493	You need to get it on a star diagnostic machine. Im sure you would have saved a hell of a lot of money if you had done in the first place

30-08-2010, 03:45 AM	#3
hellgrace5 Member Threadstarter Join Date: Aug 2010 Posts: 33	I did get on diagnostic scan but there are only ASR faults. ASR light was on and i solved it by replacing the electronic throttle valve. Now no more ASR light. Engine cut off when hot is stil there.

30-08-2010, 09:18 AM	#4
grober Hardcore MB Enthusiast Join Date: Jun 2003 Location: Perth, Scotland Car: W204 C200CDI Estate Posts: 14,436	Because its a V8 with 2 distributors and 2 coils it would be unusual for both high tension supplies coil/distributor/rotor arm/leads plugs to fail simultaneously so some cylinders should fire. I guess you need to look for a " global" failure which effects the complete engine. Does it just cut out suddenly or missfire for a while before stopping? A quick test for the ignition control unit [ I assume there's just one? the v12 has 2 I believe?] would be to get an electronic component freezer aerosol Freezer Spray : Freezer Sprays : Maplin and give it a quick "chill" --- If this restores function you may have your answer

30-08-2010, 10:35 AM	#5
hellgrace5 Member Threadstarter Join Date: Aug 2010 Posts: 33	Yes it has only 1 ignition module. Before it cuts off there is always an erratic idling situation like rpm is not steady then cut off. What you mean is to spray some "chill" to lower down the ignition module temperature when its hot and unable to start ? Will keep on update. Thanks!

30-08-2010, 11:01 AM	#7
hellgrace5 Member Threadstarter Join Date: Aug 2010 Posts: 33	The module cost is way too expensive. Oh my.. Hopefully its not the ignition module.

30-08-2010, 11:33 AM	#10
hellgrace5 Member Threadstarter Join Date: Aug 2010 Posts: 33	So do you suggest I open up the unit and chill it inside or just spray the outer part only ? Thanks.

30-08-2010, 11:34 AM	#11
grober Hardcore MB Enthusiast Join Date: Jun 2003 Location: Perth, Scotland Car: W204 C200CDI Estate Posts: 14,436	THIS IS AN EXCELLENT SITE FOR YOUR MODEL K6JRF Auto Page

16-11-2011, 11:02 AM	#13
Shane10010 Member Join Date: Nov 2009 Location: Northampton Car: 2003 S320 CDi Posts: 78	Anyone know if this helped isolate the problem?

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