Help needed with my W124 engine

[zedmeister]

I bought a 1996 E220 cab. There are a couple of issues that I want to sort out. The main one is that starting from cold, it smells very fuelly and has an erratic idle :

Erratic idle

Rev counter

When slightly warm

As you can see, it settles down when slightly warm. However, it still smells fuelly. Also the revs really dip when braking and coming to a standstill but it does not die, and picks up then when stationary.

Any advice on where to start? MAF sensor or O2 sensor maybe?

Thanks!

 

[mioba]

A merc indy before you throw parts and money at it.

The W124 has alot controlled by vacuum, so look at hoses.

 

[zedmeister]

A merc indy before you throw parts and money at it.

The W124 has alot controlled by vacuum, so look at hoses.

I totally agree but how many people are catering for these older Mercs? I also often find that parts are cheap but labour isn't!

 

[LostKiwi]

8d start with something tha can read codes and live data. Carsoft (not iCarsoft) do units that can read these older ECUs

 

[zedmeister]

What type of connector do I have on the w124 and what kind of data would I get if I spent £200 on the carsoft kit? Would it give me specific fault codes for items or more general information?

 

[zedmeister]

I already have an iCarsoft. I realise that you are talking about carsoft but is there any way I can connect my unit via an adapter?

 

[LostKiwi]

I don't think iCarsoft supports the 124.
I have seen an iCarsoft adapter for OBD2 -> 38 pin but have no idea how well or otherwise it works. I have used an adapter cable with an i980 but frankly it was not a lot of use as it only read engine codes and not many of them.
At 1996 your car probably uses the 38 pin round connector (same as my 93 R129) Easiest way is to have a look.

 

[zedmeister]

I don't think iCarsoft supports the 124.
I have seen an iCarsoft adapter for OBD2 -> 38 pin but have no idea how well or otherwise it works. I have used an adapter cable with an i980 but frankly it was not a lot of use as it only read engine codes and not many of them.
At 1996 your car probably uses the 38 pin round connector (same as my 93 R129) Easiest way is to have a look.

Just had a look and my car has the old 16 pin connector - the one with 4 pins to one side, etc. What can be read on one of those? Is it compatible with anything?

 

[LostKiwi]

Just had a look and my car has the old 16 pin connector - the one with 4 pins to one side, etc. What can be read on one of those? Is it compatible with anything?

Sorry I have no experience of that connector.
You could ask Carsoft www.carsoft.com if they support it. They list the 14 pin connector ,- are you sure yours isn't 14 pins?

 

[zedmeister]

Its this one

 

[Joe2mercs]

To read the 16 pin socket you will need a ‘blink code reader’. They are very simple and can be made for about £5 I attach a picture of the one 8 knocked up. It consists of a diode (blinks when reading), a contact switch (small red button on top of box), three wires with banana plugs. I clear plastic rugby ball shaped thing is an in-line screw together fuse holder. The instructions are: black plug into socket 1 (earth); yellow into socket 8 (engine faults); and red into socket 16 (12 volt supply). Key on, engine off (don’t start the car), then press the red button (the contact switch on the reader) for 2 to 4 seconds, then count the blinks. For multiple faults there will be space of about four seconds between sets of blinks.

Your car is an HFM (hot film measurement) fuel injection, which means it uses a mass air flow sensor (the collar thing on the air duct immediately after the air filter box) rather than pressure measurement system (PMS) that was on the 2 litre M111 engine. Your engine is the same block but 10% greater capacity.

I noticed that your engine is a bit chattery when running. This likely to the fan belt dampener (Mini shock absorber), top bushing gets a bit loose with age. It’s located just the right of the thermostat housing. With the engine running, if you press on the top of it with a screw driver h just to keep your hands away from the fan belt) you can stop the chatter sound as you apply pressure. They are pretty cheap from Autodoc or GSF.

I think your engine running roughly is due to the insulation beginning to fail on the injector wiring. To fix it you will need a roll of black insulation tape and a pair a scissors and about half an hour. Each injector is supplied with pair of wires wrapped in a cloth based tape. Take this tape back to expose about three inches of flex, if I am right the plastic insulation will be brittle and crumbly. Now wrap each of the wires independently using the new plastic insulation tape. I find the best method is to cut lengths of tape about an inch long, post it between the wires and fold it over, sticky face to sticky face. Then add the next bit of tape slightly overlapping the previous piece. Once a length of wire is completely insulated the tails of tape can be cut neatly. When both wires are insulated wrap them together in a spiral of insulation tape. My engine used to buck and kick when running and was showing signs of becoming difficult to start until I did the above job and now it runs like new. It is worth checking the last few inches of insulation on any of the wires serving sensors on the engine. A combination of heat and poor choice of plastic by Mercedes leads to insulation crumbling and causing shorting with age.

 

[zedmeister]

To read the 16 pin socket you will need a ‘blink code reader’. They are very simple and can be made for about £5 I attach a picture of the one 8 knocked up. It consists of a diode (blinks when reading), a contact switch (small red button on top of box), three wires with banana plugs. I clear plastic rugby ball shaped thing is an in-line screw together fuse holder. The instructions are: black plug into socket 1 (earth); yellow into socket 8 (engine faults); and red into socket 16 (12 volt supply). Key on, engine off (don’t start the car), then press the red button (the contact switch on the reader) for 2 to 4 seconds, then count the blinks. For multiple faults there will be space of about four seconds between sets of blinks.

Your car is an HFM (hot film measurement) fuel injection, which means it uses a mass air flow sensor (the collar thing on the air duct immediately after the air filter box) rather than pressure measurement system (PMS) that was on the 2 litre M111 engine. Your engine is the same block but 10% greater capacity.

I noticed that your engine is a bit chattery when running. This likely to the fan belt dampener (Mini shock absorber), top bushing gets a bit loose with age. It’s located just the right of the thermostat housing. With the engine running, if you press on the top of it with a screw driver h just to keep your hands away from the fan belt) you can stop the chatter sound as you apply pressure. They are pretty cheap from Autodoc or GSF.

I think your engine running roughly is due to the insulation beginning to fail on the injector wiring. To fix it you will need a roll of black insulation tape and a pair a scissors and about half an hour. Each injector is supplied with pair of wires wrapped in a cloth based tape. Take this tape back to expose about three inches of flex, if I am right the plastic insulation will be brittle and crumbly. Now wrap each of the wires independently using the new plastic insulation tape. I find the best method is to cut lengths of tape about an inch long, post it between the wires and fold it over, sticky face to sticky face. Then add the next bit of tape slightly overlapping the previous piece. Once a length of wire is completely insulated the tails of tape can be cut neatly. When both wires are insulated wrap them together in a spiral of insulation tape. My engine used to buck and kick when running and was showing signs of becoming difficult to start until I did the above job and now it runs like new. It is worth checking the last few inches of insulation on any of the wires serving sensors on the engine. A combination of heat and poor choice of plastic by Mercedes leads to insulation crumbling and causing shorting with age.

Thank you for taking the time to write such a detailed reply! I'll knock one up and give it a go and also look at the wiring. Thanks again!

 

[Joe2mercs]

Just to add that when you need to clear codes press the red button (momentary contact switch) for ten seconds.
Here is the schematic that I usEd to make the device that I included before. this link should take you to the manual that tells you what the blink codes mean (https://www.mbslk.de/files/artikel/r170_fehlercodes.pdf)

 

[zedmeister]

Just to add that when you need to clear codes press the red button (momentary contact switch) for ten seconds.
Here is the schematic that I usEd to make the device that I included before. this link should take you to the manual that tells you what the blink codes mean (https://www.mbslk.de/files/artikel/r170_fehlercodes.pdf)

View attachment 75410

And the fuse goes on the test cable I presume?

 

[Joe2mercs]

Yes, in the yellow test wire. It can be run without a fuse but I added it in just for safety. I am a bit paranoid about such matters so I am a bit cautious. Good luck

 

[zedmeister]

I have the codes from the engine and need some help from you guys to work out what to do next. I have the following blink codes from socket 8 (HFM): 8 blinks, 13 blinks and 20 blinks. These translate to:

008 P1132 Oxygen sensor (G3/2) circuit "rich" stop
013 P1138 Oxygen sensor (G3/1) operating condition
020 P030X Cylinder X misfire detected

Now the last one says cyl X - how do I know which cylinder? Also, does it look like the O2 sensor needs changing or should I work out the misfire issue first?

 

[zedmeister]

Actually, I don't know if I read the correct page of the manual. I used page 45 of the manual but there are HFM codes on page 22 as well????? Help! If its page 22, then the blinks mean:

8 (011) Engine idle speed contact Throttle valve position too large
13 (015) Throttle valve potentiometer actual value too low.
20 (024) O2 sensor (before/upstream of Cat. Conv.), open circuit

Really confused now

 

[zedmeister]

Anyone?

 

[DREAMER NO2]

First thoughts to you is replace the ht side plugs coils do you know when these were last replaced ? ,,and check all vacuum lines .. Could be vacuum related .

 

[zedmeister]

First thoughts to you is replace the ht side plugs coils do you know when these were last replaced ? ,,and check all vacuum lines .. Could be vacuum related .

How much of a 96 M111.960 engine is vacuum controlled? I thought it was mainly the older ones like 230E, etc and not the newer ones? The error codes are pointing to the throttle (a well known issue) and o2 sensor I think?