HAVOCK

Hey everyone, I have a question that I hope I can receive help on. On emission my 89 190e 6cyl blew high on HC/CO = Hydrocarbon & Carbon Monoxide. I had the valve seals replaced, and my O2 sensor light is working but not on to indicate a replacement is needed. I have given it a tune up also my HC = 3.0535 & CO =48.6325. Any ideas?

Mr. Vanos

Havoc-

First, welcome to MBWorld! The "Forum Questions & Help" forum is for questions regarding the forum, not for automotive technical issues. I will copy your post to the appropriate forum ("Mercedes Tech Talk"). Below is the link:

johanson

I need help please I have a 1984 benz 190E whith 168000 emission are high ,I change 02 sensor and cathaletyc conver used fuel cleaner dut no chage ,tthe light for o2 sensor still on needs to be reset? to make 02 sensor work

Mr. Vanos

No the sensors will work regardless. You will need to reset the light as it may be a hard error in the DME. Once reset, you wait to see if the light comes back on again. If it doesn't then you are ok. If it does, then you need to scan the car for OBD1 codes to see what the exact error is. A check engine light does NOT necessarily mean O2 sensor or cat problem, although those are the more common occurrences.

johanson

Some want plase help what is a dme

Mr. Vanos

DME is the car's ECU or computer that controls engine management, emmissions, ignition, fuel/timing, among many other things. It is also a place where check engine errors are stored. Your car conforms to OBD1 (On-Board Diagnostic 1 standards) for the year of the vehicle. When you plug an OBD1 diagnostic tool to the car's OBD1 port, you can then read any errors the car is experiencing, including faulty O2 sensors or catatytic convertors.

johanson

wall: : My 190e 1984 has a relay or box by the computer that has a fuse on top it ,fuse was out but I replased and now engine idle up and down.If I take fuse out it idles fine went fuse is in looks the gife a litle more power( but why engine idle funny now

canada011

Hy Johanson,
I'll try to help you like I can.

First of all that fuse is on a little silver box with Red cover? Its the Over Voltage Relay Protection, commonly called OVP. There is only 2 things that can change the rev of youre engine when on idle: 1- the air/fuel mixture 2-the air idle valve(this valve has alot of synonyme name ). This valve lets more or less air entry to the engine to keep the idle rev stable. I would guess on this valve and that the OVP is putting that valve on. For now, I would suggest you to remove that fuse so you have a stable idle speed. This is an other problem, I can not garantee but I think.

Next, are 190e car has its own diagnostic system. There is a round socket in the enginebay called the X11 diagnostic socket with like meaby 10pins... I dont remember... When you put a voltmeter between pin no. 3 and ground you should see a variating voltage between 0.2 and 0.6V, that represent the O2 reading of the O2 sensor of youre car. BUT: when it doesnt vary and gives a constant value, than that is telling you that there is an error code. There is a chart where you can see at what this constant voltage is refering of error. Here is the chart:
http://www.190revolution.net/forum/v...r+code&start=0

You have to use this formula to determine the code:
(1 - V(pin3)/V(battery))*100% = code

Are car doesnt has OBD, its Pre-OBD.

Finally, if the voltage is variating between like 0.3-0.6V than you can go further in the testing: You will have to directly take the reading at youre O2 sensor too see if the mixture is correct and stockiometric. You have too see if the mixture oscillate between a 0.5V directly at the O2 sensor to see if the ECU is trying to keep this value. To doo so, you have to lift the foot carpet of the pessanger side seat. You will see a big green cable, you will have to plug a multimeter between this green cable and a ground. See what is the value (it most be between 0 and 1V, else you are not pluged at the good place). Come back here to give us youre value. All this is obviously at idle.


When you will be sure that the O2 sensor is giving some correct reading and that is showing that the ECU is trying to keep around a stockiometric (less poluting) mixture value, I will help you too go further in the diagnostic.


So in summary:
1-look on the X11 socket in the engine bay for the voltage value. If the voltage is constant there is an error, look at the table to see what it is. If the voltage is variating pass to the next step.

2-Lift the carpet and take the O2 sensor voltage value, see if its variating and between witch voltage. Come here tell us youre values.


For know that is what you should do. I will give you more hint after that

Good luck!
Jeremie

johanson

Thakns so much for your help

canada011

No problem
Even if you see a constant voltage at the X11 pin 3, could you still take the voltage of the O2 under the carpet please? I am curious

johanson

I will take voltage under carpet this friday and I will let you know.Can you please teel me how do I know if the air flow meter in my car is working.1984 190e.My car runs whith 30% better, more power etc thanks to you:

canada011

^
Cool! What did you changed to get that 30% increase?
Did you saw any error code at the X11 ?

For the AFM, you need to mecanicaly verify if you have the correct zero position:
http://www.190revolution.net/forum/v...=asc&start=200


That tread explain all what you need to know on AFM and even more :P
Its only a mecanical thing. Forget the AFM electrical potentiometer, it isnt really important. Only the mecanical lever that is attache to the AFM plate that push on the pin of the Fuel distributor is important to have a good setting...

Give me news about youre O2 reading

johanson

I will take voltage this sunday I keep my soon home and I did"t have time for my love[190E] I will send you email sunday.That picture you send me is that right went you take air filter out and you see a round plate? Went I take fuse out power goes down and I catn keep deht center I have to go to30 degrese but went fuse in his fine in deth senter you may thing I thanks for your time you have tech me a a lot

canada011

Correct, this is the good plate. Just turn the ignition on for 5 seconde, than turn it off (just to start the fule pump a couple of seconde and build the pressure in the fuel distributor). After that, the plate will take her zero position and it should be near the black line like illustrated.

Please take the voltage between pin 3 and ground. And after thake the voltage between the green wire (for the O2 under the carpet) and the ground. Take those voltage at idle after like 2 minutes of idling...

I dont see what you are talking about for the fuse and the 30degree? Witch fuse and what are does degrees that you are refering to?

johanson

Hi Mr vanos. Today I tested the green wire for o2 sensor and reads 0.5 ,but in X socket you say to chek x11 but only goes to #9What do I do now .Mr vanos do my car has a egr valve or Egr filter I catn fine a egr valve on line, only egr filter can the filter make car high in Hc/CO? where egr valve is locate or egr filter? ones Againg thaks for your time

canada011

Is the 0.5V fluctuating? Between like 0.4 - 0.6V ? If yes than youre mixture is good and you dont have any problem at idle.

Whe dont have any EGR valve or EGR filter! lol
Neither OBD system

Fore the socket: You finded the socket with the screw cap on it? The round socket on top of the left wheel arch in the engine bay? Just beside the big Greed wire that goes to the Ignition module? If its a round socket with a couple of little hole with numbers on them then it is the X11 connector.
Put the multimeter between the pin no.3 and a ground and take the reading

But whatever you find at the X11, if you have a voltage that fluctuate between 0.4-0.6V at the O2 sensor than the mixture is perfect at idle. Do you here any missfire or weird sound at idle? If no, than everything is ok at idle. If ther is alot of emmision of HC than it is meaby du to bad piston rings. How is your oil?? Catalitic converter doesnt eliminate HC I think, so it isnt a bad converter I would guess.

Little question like this: do the test is made at idle or not?

johanson

HI on x box in#3 reads 04 05 06 and green wire reads .005 why two 00? test done in Idle after two minutes like you say This is good or not?

johanson

Mr Canada. the AFM is not in zero position how do I fix this problem ?thanks for your knowlege and timeI verry happy for your help, you ask me before how increase 30% more power by the computer is a box whit fuse on top if I take out it gets LZ went put fuse back on it runs much better you may think this:

canada011

Sorry, I dont understand what you mean... What is the voltage between the pin number 3 and the battery ground? Put 1 wire of the multimeter in the pin 3 and the other wire directly on the battery ground... Put youre multimeter in Volt. You should read between 0-5V ... probably around 2.5v ... no?

For the AFM, can you take a pic of youre actual AFM plate position?

And for the O2 sensor, it is important to know if it is variating and between witch values. You said it was at 0.5V, but is it variating? Between witch values?

THanks!

johanson

Hi SR. I took readings for pin 3 directly from battery ground like you say and reads .634v and .635v same whith green wire and reads (variating between this values .oo2v .oo4v and .005)note I took this readings whit a digital voltemeter. I dont" understend why is reading .002v .oo4v etc on green wire went it should be only 0.5 (battery reads 14,6v) I have a valve on top of in take manifoll it has two hoses and a electrical conection whith a plastic screw can you tell me name of valve what is for please?Thanyou verry much for you time and triying to get my car running well

canada011

First of all for the X11 pin 3:
If you readed 14V at the battery than your voltemetre is correctly setted. Good. And you said that you waited more than 1 minute of engine runing before taking the values perfect. And this 0.634V is really between the battery ground and the pin3?

You read 0.634V at the pin 3.
You read 14.6V at the battery.

The formula is:
1 - V(pin3)/V(battery))*100% = code

that gives you:

(1- (0.634/14.6) ) * 100% = 96% ... Impossible...

For the Pin 3 you should read some values around 5V ... (so that gives around 50% )

Or you have an open circuit or you are not taking the reading correctly...


I need to know: WHAT green wire are you talking off??
THe green wire of the O2 sensor that is under the carpet of the passenger side?? Or are you talking about the green wire in the engine bay?(because that last wire is a compleat other thing) Are you sure that you put 1 lead of the voltmeter on this wire and the other lead on a REAL ground??? Try to take always the ground of the battery...

The value of the O2 sensor (that green wire under the carpet and the ground) should give a value between 0.1V and 0.9V... AND it should variate.
Here is an exemple of O2 sensor reading:
"Having a voltage fluctuating between 0.35V and 0.65V" Than in that case everything is ok!

Having a voltage that is fluctuating like between 0.48V and 0.52V IS NOT a good value! The O2 sensor ISNT giving the correct value!

So, please Forget for know the values at the X11, take only the values of the green wire under the carpet and be sure to use the ground of the battery please! Between What value the voltage is fluctuating ?? (wait like 2 minutes of running engin befor taking value please)

Sorry, but we really need to be SURE of that O2 voltage value! Everything is determinated by that... I will wait youre value, please double check it

canada011

If it is cylindrical and has some plastic tubing on it that it is the Cold start valve, the valve that is controled by the OVP relay I think (the relay where you founded youre blown fuse). That is what allow more air to enter the engine when engine cold and this is also what control the idle speed of the engine.


If it has a blue cap and a metal line on it, than it is the Cold start injector. That is what puts a shot of fuel during cranking for an easier start of the engine

johanson

I took readigns for green wire under carpet o2 sensor idle for 3 minutes and I ground from battery, it reads "here we go" between .490v and .890v.X pin reads olso from battery ground .632v and.634v. battery reads 14,24v If this dont sound right I will take them againg.and you can do this:

johanson

HI me againg I took v of green wire02 sensor,I made a litle hole in the wire and ground to battery. Or I have to unplug green wire of sensor en take reding just of the green wire whith out been plug to sensor?

canada011

Now you are talking!

That is exactly what you had too do! No dont disconnect the wire of the O2

So you are seing between .490v and .890v !

So you are almost stockiometric (meaby a bit lean but neglectable) ! That means that there is no problem at idle AND that your ECU is correctly correcting the mixture, else you wouldnt be soo close of the stockiometric mixture of 0.5V

The x11 reading of 0.632v and.634v is no good... I dont know why, but it should not give those values... Something is wrong, but its not really important since youre O2 sensor is telling you that the mixture is good! So forget the X11 and lets continue the diagnose with the value of the O2! Trust me for this!


Ok, so Now we need to know if youre exhaust gas is correct at Idle? Is the excess CO and HC at idle speed? If not, at witch RPM was it tested?
If it was test at idle speed thant something mecanical is wrong, like valve or pistons/rings (except if youre O2 sensor is REALLY old), was the O2 sensor changed recently?

So I am waiting youre answers for those 2 questions!

If you have the chance please do this 2 other tests:

1- You have a little black box plugged on the Fuel distributor, it has an electrical connector on it, it is caled the EHA (Electro Hydrolic actuator), are car has a compleately mecanical injection EXCEPT this EHA. This EHA can control a bit the fuel mixture and is used by the ECU to keep the Air fuel ration close of the 0.5V that you where reading. Normaly even without that EHA control you should have a mixture close of 0.5V. That is what you should test... To do so:
Just unplug the electric plug that is on that EHA, than take again the O2 reading like you did. Notes between witch values the voltage is fluctuating. Give us those values please.

2- Replug back the EHA like it was. At idle take again the values of the O2, and gradually increase the idle speed with the fuel pedal. Note at witch RPM the values of the O2 sensor is out of limit (inferior limit is about 0.2V and superior limit is like 0.9V). In summary, note the RPM at witch the reading is toping off... Give us this RPM...