m110 280 sel rich exhaust fumes

[Kris P.]

HI Guys,

I have a 280 SEL that I just recently rebuilt its engine.  SO far everything's doin well except for the "rich" smell in the exhaust.  Mine is a d-jet,  anything I can do to adjust its richness in the exhaust fumes... what are the basic steps that I should take in fixing this problem.

[carl888]

This should get you started Kris:

http://www.benzworld.org/forums/w116-s-se-sel-sd-class/1223523-bosch-d-jetronic-k-jetronic-troubleshooting.html


http://pdfdatabase.com/download/the-bosch-d-jetronic-fuel-injection-pdf-11916911.html

Although the above is for the Renault 17, the fault finding section is the same.

Regards, Carl

[Kris P.]

Thanks carl.  I saw the site and its a big help.  By the way, the car died on me yesterday.  I gave a big knock on the box on the left most side of the engine bay which is connected to the distributor (where the green wire connects to) and the car started and pretty much made the car run better, lesser fumes.  Im starting to get dizzy to where Im supposed to start my troubleshooting process so that I could fix this problem...

[Nutz]

Disconnect the Temperature Sensor I on the snorkel of air cleaner. This is an old trick to remedy rich running. Have you inspected the wire from the ICU and distributor thoroughly for damage? Also, is the hose to the MPS tight and not damaged? If this all checks out and the condition remains, check the resistance of Temperature Sensor II. It should be between 3000 and 4500 ohms and below 1000 ohms after warmed up. If this is defective, you'll get a rich running condition due to it having an open circuit, in sense driving the MPS crazy trying to correct it.

[Kris P.]

I did check the wires to and from the distributor, seem all are in place.  I also cleaned all ground terminals from the injectors to the the ICU.  The temp sensor II is located at the cylinder head (the one ith the small flat terminals) along with the other sensors right? if this part is defective, would it cause the engine run a bit rough and have little misfires when I rev it steady at 2500 rpm and up? as for the temp sensor 1, I'll disconnect the wires from the sensor itself and just cover the terminals?

[Nutz]

I haven't ever seen a D Jet M110, so its location is unknown to me. Yes, Temperature sensor II will cause it to run rough if it shows an open circuit.

Also inspect the ignition system (plugs, wires, cap and rotor) for defects.
How old is the accumulator?

[Kris P.]

Well I noticed that my d jet doesn't have an accumulator (that's the one near the fuel pump located underneath the car right?, like the ones with the 124's right?).  If you were to check the brackets and all, all seem to be original and there's no provision for the accumulator so I think there's none.  If originally there's none, would it improve if I install one? I have spare accumulators from my 124's...