I know it is New Year Day but I cant focus on anthing else....

I went and pulled up some blink codes maybe that will lead to somewhere.....


4) LH-SFI Right Bank:
4 Voltage at mass air sensor (MAF) with hot wire circuit insufficient or too high. Open or short circuit in
ground wire.
8 Camshaft position sensor signal. Open or short circuit.
13 Intake air temperature sensor, open or short circuit.

5) LH-SFI Left Bank:
4 Voltage at mass air sensor (MAF) with hot wire circuit insufficient or too high. Open or short circuit in
ground wire.
8 Camshaft position sensor signal. Open or short circuit.
13 Intake air temperature sensor, open or short circuit.


7) Cruise Control/Idle Speed Control:
5 Stop lamp switch - I removed third stop light for back shade repair

9 Left rear axle vehicle speed sensor or Hall-effect speed sensor
Rear axle vehicle speed sensor from ABS control module
Rear axle vehicle speed sensor from ETS/SPS control module
Incorrect CC/ISC control module installed ETS signal
10 Engine speed (RPM) signal (TNA)

8) Base Module

8 Voltage supply for LH-SFI control module interrupted
9 Voltage supply for LH-SFI control module interrupted
10 Voltage supply for LH-SFI control module interrupted
Voltage supply for fuel injectors interrupted
16 Voltage supply for electromagnetic a/c compressor clutch interrupted

 

I know that feeling all too well (for me it was on my birthday morning, which dampened the festive mood a bit)

I have no experience with blinking error codes (my W140 was a 96 and did not have that).
Are you aware if the blinked codes are present ones of if they are also stored?
I would guess that they are stored?

The first thing I would do that is relatively simple is to check the wiring harness for continuity (you will need a simple electric multimeter and maybe some long arms).

you can probably find the schematics for your car at : Web ETM Model 140
(there are a lot of different versions to chose from, so pick the right one)
you will also need some DWF-viewer plugin should your browser not support it

Also, if you click the diagnostics tab once inside the schematic, you can do some measurements on selected pins to see if some of the sensors etc are good (like, this and that pin should have ca 10kOhm)

hopefully this will get you some bit on the way.

Also, what happend to me was that the engine ran perfectly (or maybe the odd cough), or then not at all. one day it was a no start situation.
The culprit was bad motor mounts. they had colapsed, enabeling the engine to move around a bit more than it should. As the ECU was located next to the firewall, there was a big cable bundle (some 60-70 wires) jumping over from the motor to the firewall. (this was on a V8, but I assume the ECU is sort of in the same place on the v12)

as the engine moved more than usual the copper had snapped inside the insulation on the crankshaft position sensor, causing the ECU not to sense any crank, and thus no fuel or spark were provided...
I ended up changin the harness and the mounts.

With this said, if all wiring seems fine when you measure it, try to wiggle it around in problematic spots to see that provokes anything.



Good luck and happy new year!

 

Thank you for reply.
That put new light on my situation.
Will definitely look into mounts and definitely use schematics.

My thought was it may be something with crank or cam sensor but it could be something electrical.

I also wait for new star diag to arrive ( one I have was good only for a year)

I love the car. I can get mad and frustrated but one trip in it compensates everything and make me happy man.

 

Well, it can still be anything. My best troubleshooting advice would be to suspect everything. Let me know what you figure out!

 

My car is 92 600SEL as well ( Cats deleted by factory ) i added high flow cats .
I did & had the same issue as you .
Removed Manifold etc etc then all new .
Car ran perfectly but then started to misfire & low power .
I have the C5 scanner & by scanning it ,it throw all kind of weird codes .
I checked & rechecked all new parts i installed were installed correctly which they were including torque nuts & bolts even the sparkplugs .
The problem was , booth Distributor Caps inside had oil & degreaser deposits in them . Cleaned them all up as new & VOILA , No more power missing or misfiring.
Car runs perfect up to this day .

TIP : Delete - Erase all codes - clean distributors - Drive the car then Re scan it . Chech all fuses including the 4 inside ecu box .

 

Thanks Merc-S600,
Just temoved them now to check maybe moisture got in but I dont see any bad signs of anything.
Maybe someone will notice something so I attached pictures of it. Other side looks same.
Have to try everything.

 

Fuses good but I put new ones anyway.
Car cannot be driven.

How could I check crank sensors and cam sensors?
I know I could check resistance but how to do it in this instance?

 

Did you check your Cam sensor conections are thight connected at firewall. Crank sensor at icm , make sure no corrosion is anywere .
Re check if you removed the ECU modules that they are seated properly ,flush with the edge of the case .
If your cam sensor is gone , engine will vibrate . Crank sensor gone , Hard starting & when engine gets hot ,Stalls completely .
Your Dizzies look good to me .

 

To check your engine mounts ( not that they have anything to do in relation to your problem ) , look at the top of the MAF's , engine manifold edges should be about 1 inch higher then the MAF's .
If Engine mounts are finished or there abouts , all you get are vibrations on steering wheel & overall in cabin ,nothing else .

 

Thanks Merc-S600 for all information.
In regards to sensors.
Engine when started vibrates/shakes as I think it is caused by missfire.You can smell gas a lot.
When I barely got home after it start to misfire I shut it off and after few min tried to start back and it stalled after few seconds. Had to start again and it did but run poorly.
Know it starts cause it is stone cold but again after few sec when revs drop it runs poorly.

I woul replace cam sensors as it woul be easier however those are expensive.

Crank on the other hand are hard to get. I read somewhere it can be done by removing firewall?

 

When you re installed the Manifold , did you make sure it's properly Torque'd and used new gaskets . The Gas smell shouldn't be there check Throttle Actuators .
Check your Gaskets by all that you removed for leaks . Check the Airhoses are conected properly .
Get a can of Carburator / injector cleaner even Brake calliper spray is good . Start engine then spray it at locations were a leak is suspected .
If a leak is anywere the revs will drop dramatically .
I dont think it's Cam sensor fault .
How old is the petrol in Tank & how full is it ?.
Refer to my Thread that i also suspected Bad Camshafts but ended up being bad petrol .

 

When installed manifold I used all new gasket and torqued to specs.
After I put all back together I used smoke machine to find leaks but there were none.
Will redo it though as to be sure nothing happened.

Will need to check throttle accutators (they look like someone replaced cables as they look like new)
If I put ignition on but no start and press gas pedal both should have open in same way?


I removed cam sensor now and I dont know if you can see on picture but wires are visible
Could it affect it somehow

 

Cam wiring look ok . That corrosion there is only at the end ,mine has it as well.
I replaced booth my Throttle Actuators as 1 made a weird ticking noise at start up . Not to guees around why it ticks ,i just relpaced booth ,problem fixed lol.
Booth Throttle Actuators with Ignition on , need to have the HUMMING noise ,if 1 dosent have it ,you found the fault .

 

Just checked both are Humming.
I disconnected and connected but nothing changed after firing up.

Just read couple of discussions on this forum and one scared me. I hope it doesn’t have anything to do with compression…..

 

If it ran perfectly before , i see no reason why it would be compression fault , i highly doubt it .
You didnt disconect any of the HT leads at Distributors , No ?.
If thats the case ,perhaps 1 or more cables are wrongly connected .
I dont think you would but just to mention it.

 

Just Re read your original Post #1 , Yes you did remove the plugs .
Did you make sure they are on the corect Cylinder . Check Firing order.
On original Dizzy caps , there is a # for each plug to whi h cylinder it goes .
M120 600SEL Firing order here.

firing order 600 sel 1991 ?

Hi , Does anyone knows what the firing order of an 600sel W140 1991 is? I think the previous owner mixed up 2 or more cables while changing them... At least i want to check to make sure... Greetings René

www.benzworld.org

 

Thank you for that thought
As a matter of fact I recall I did have some problems with wires.

Just went to the car and passenger side (left hand standing in front of the car looking at engine)are connected acording to markings on caps just copied them on paper now
the driver side I figured from link you provided.
Does it look good or I messed it up?
Not sure if you can tell from my deawing

 

I’m new to the Benz, but I have three other Daimler vehicles.
check to see that you have proper voltages. My diesels alternator randomly doesn’t start charging for several seconds to minutes, causing a drop below 8vts, and sets of the open circuit type codes you are getting. Could be a broken wire, bad connection or bad ground.
Had to chase aground problems on a trailer that was caused by corroded bolts away from the problem area.
Start at alternator to battery, and work back to the bro let fro there.

 

Thanks Ken
Will check tomorrow. When was driving last time had my phone charger that shows voltage and it was a little over 15v. but you never know.

 

It looks to me that you crossed cylinder wire 7 with 8 , easily mistaken .
Going by your drawing ,not to sure if it's correct way up-down etc , you check.

 

Will switch 7 with 8 just to be sure.

BTW Chris saw your post with your 600. It is beautiful. That was a lot of work you put there.

 

Ok wires look good.

I also checked voltage on battery before and while car was started seems fine.

 

Voltage is good .
How did the engine go by swapping cylinder 7 with 8 wires ?.
Yes ,a lot of work has gone into the black 600SEL which runs absolutely FLAWLESS . Which one did you see , the silver 1 - brown 1 or black 1 ?.
Have you downloaded the 600 manual yet ?.

Merc S600/600SEL Workshop Manual here now

GO HERE FOR THE DOWNLOAD::: >>>>>>>>> https://www.dropbox.com/s/jotpz7hyevflaqg/Mercedes%20S600%20Workshop%20Manual.rar?dl=0

www.benzworld.org

 

Black one you took over from Joe.

Thanks for all the input.
I thinking now that one bank is not getting spark and wouldn’t that be controlled by cam sensor?
I gues I will need to wait for C3 Star to arrive or source cam sensors.

 

No . Camsensors even if deactivated still run 1 bank ,poorly but operative .
Check your Coils on each side are conected properly at Distributors .
Check your ICM's at Fenders all is conected & inserted properly ,same at Firewall cable chanel .
Swap over your ECU's for Bank 1 to bank 2 ,it's the 1st 2 at front of ecu box labelled LH0009 v12 etc, see if engine behaves differently . Make sure they seated properly .
Check your Injectors are inserted properly , you mentioned gas smell , Check .
Disconnect booth MAF conectors while engine is running , hear the engine change tune .

Yes, that black 600 was a lot of work .
Engine as she stands of today .