W124 280E-24V decat lambda sensor question

[LordW124]

I'm soon decatting my 1992 280E-24V though I'm quite new to the subject and don't really know how to proceed.

It has to be done since I don't feel like shelling out money for a new cat and it's really acting up.

To get right down to the subject though I did some research and found the lambda sensor alters the air fuel mixture (to get rubbish in the cat out of the way? idk but it's literally burning through fuel ) but I'm not sure what my options are.
I found this website
And the instructions tell me to adjust the sensor and go for a drive, but do I need special tools to see what's the best or is it in some way visible?

Has anyone maybe done this before or have any product recommendations for a decent o2 sensor simulator?

EDIT: also, might this be what I'm looking for instead of that adjustable (and expensive) one?

 

[PobodY]

Why not just leave the lambda sensor alone (or put a new sensor in)? - It's giving the feed-back for closed loop operation to the ECU and should be before the catalytic converter (hence testing the mixture as it comes from the engine).

In what part of the map is it over-fuelling? Maybe the only problem you've got is that you need a new lambda sensor to get the fuelling back on-track.

Unless I'm mistaken, in 1992 they only put one sensor in the exhaust; it's only more recent cars that have post-catalyst sensors. - If you've got something in the catalytic converter, that's just a temperature sensor to warn you when you've got it so hot it's likely to set fire to something.

My 1990 Nissan runs fine without a catalytic converter and the lambda sensor in an after-market 3" turbo elbow (although it runs a titania sensor rather than a zirconia one).

 

[LordW124]

Why not just leave the lambda sensor alone (or put a new sensor in)? - It's giving the feed-back for closed loop operation to the ECU and should be before the catalytic converter (hence testing the mixture as it comes from the engine).

In what part of the map is it over-fuelling? Maybe the only problem you've got is that you need a new lambda sensor to get the fuelling back on-track.

Unless I'm mistaken, in 1992 they only put one sensor in the exhaust; it's only more recent cars that have post-catalyst sensors. - If you've got something in the catalytic converter, that's just a temperature sensor to warn you when you've got it so hot it's likely to set fire to something.

My 1990 Nissan runs fine without a catalytic converter and the lambda sensor in an after-market 3" turbo elbow (although it runs a titania sensor rather than a zirconia one).

Aha I see, didn't pay attention to the sensor location (since these products all say they're for post cat sensors).
The sensor is fairly cheap and in that case it might be best to just replace that together.

Pretty sure the cat is broken though because it rattles

I couldn't find a lot of information, I think 1993 models and onwards have that post cat sensor

I'll check where the sensor is located just to make sure. I'd try and see what difference it makes but then it'd be too late to return to stock

 

[grober]

http://www.berlinasportivo.com/Technical/lancia/Thema832/Bosch-KE-Jetronic-OCR.pdf
see the section on the lambda sensor at the end. There is no "regeneration" of the catalytic converter as in what happens with diesel DPFs. The function of the lambda sensor is to keep the air fuel ratio as close to 1.0 as possible to permit optimum CAT operation. These catalytic converters last a long time but eventually choke up/collapse causing back pressure.
this is a useful page
Advance Auto Parts - Down for Maintenance

ps many lambda sensors have heating elements in them to bring them to operating temperature quickly-- these often fail with time.

 

[LordW124]

http://www.berlinasportivo.com/Technical/lancia/Thema832/Bosch-KE-Jetronic-OCR.pdf
see the section on the lambda sensor at the end. There is no "regeneration" of the catalytic converter as in what happens with diesel DPFs. The function of the lambda sensor is to keep the air fuel ratio as close to 1.0 as possible to permit optimum CAT operation. These catalytic converters last a long time but eventually choke up/collapse causing back pressure.
this is a useful page
Advance Auto Parts - Down for Maintenance

ps many lambda sensors have heating elements in them to bring them to operating temperature quickly-- these often fail with time.

According to advance auto parts bad spark plugs might be a problem, actually I changed those a couple of days ago, it seems the previous owner ran the car in a pretty bad shape, the engine was smooth but would stutter and at some point I lost ignition and the entire car would shake so I swapped them out and it's better now
The site suggests how to look in differences between cat vs the sensor but I'm confident it's the cat since it's rattling...
I suppose I'll try and see if I can somehow do some diagnostics

Also, anyone know if I need a remap after decatting?

 

[Charles Morgan]

If it's misfiring there's a high probability you'll need new coilpacks too.

 

[LordW124]

If it's misfiring there's a high probability you'll need new coilpacks too.

Yes, I replaced that entire portion of the engine where the spark plugs are including the wires, I still need to change some filters though

 

[grober]

With a "before and after" 2 lambda sensors set up you would possibly need a remap without that second dummy emulator . Can't see it as being necessary with one. The injection system can operate in fixed mode to shorten cat warm up times when the engine is cold using more fuel in the process. If the engine temperature sensor is malfunctioning the car may continue to run rich after its warmed up.
Can you tell us exactly which engine/injection system you have ? Is it the later M104 engine without a distributor?

 

[LordW124]

With a "before and after" 2 lambda sensors set up you would possibly need a remap without that second dummy emulator . Can't see it as being necessary with one. The injection system can operate in fixed mode to shorten cat warm up times when the engine is cold using more fuel in the process. If the engine temperature sensor is malfunctioning the car may continue to run rich after its warmed up.
Can you tell us exactly which engine/injection system you have ? Is it the later M104 engine without a distributor?

Yeah the engine is the M104.942 iirc, only has one lambda sensor IIRC but I need to check to make sure whether it's before or after

 

[grober]

Yeah the engine is the M104.942 iirc, only has one lambda sensor IIRC but I need to check to make sure whether it's before or after

It has to be before as its primary function is to optimise the catalytic convertors function.
its located in the down pipes just in front of the catalytic convertor ----and just behind the gearbox cross member - there may be a shield round it.

Mercedes-Benz W124 Oxygen Sensor Replacement | 1986-1995 E-Class | Pelican Parts DIY Maintenance Article

 

[LordW124]

It has to be before as its primary function is to optimise the catalytic convertors function.
its located in the down pipes just in front of the catalytic convertor ----and just behind the gearbox cross member - there may be a shield round it.
-snipped out picture-

Mercedes-Benz W124 Oxygen Sensor Replacement | 1986-1995 E-Class | Pelican Parts DIY Maintenance Article

Aha, I see.
So I just ordered the part and I'll run it without exhaust to see if it runs before proceeding with bypassing the cat to be extra safe but in this case it should probably if I understood correctly