M103 Problem With EHA Adjustment?
 

Hi All:

First off, a big Thank You to stevebfl, joeym, ozzy and inetd who helped with my power problem at wide open throttle. My '87 260E ran like it was starving for fuel. The problem got so bad, I could only muster 15 mph uphill.

The problem ended up being I think the EHA. I spent a lot of time not to mention a drained bank account trying to R & R parts. I first changed the EHA without fixing the problem then I read that it needed adjusting. From what I read a quarter turn clockwise was the ultimate cure.

I ended up turning it in one and a half turns clockwise to get it back to idle smoothly and at almost full power. This leads to my next questions to all you experts out there.

Is one and a half turns clockwise too much thus telling me that I have another underlying problem? I noticed with this setting, I have a lot of white smoke coming out from my exhaust. Possibly unburnt fuel. Not quite sure since it only happens when I gun the engine under load.

My coolant level and oil level seems to be steady so far. The car has been running fine for the past two weeks but the new EHA setting and smoke is starting to concern me.

Any advice would be greatly appreciated and Thank You in advance for anyone willing to chime in here.

Aloha,
Eric

Hi All:

Anyone with any suggestions?

Aloha,
Eric

I am no expert, but WHITE smoke is not related to unburned fuel.
Unburned fuel is normally BLACK and SOOTY.

Keep an eye on the coolant level, as WHITE smoke is most likely related to COOLANT entering the combustion chamber. And is completely unrelated to the EHA adjustment (IMHO)

I would really recomend going to Sears and buying their $30 digital multimeter that has the ability to read duty cycle

additionnal little question to experts.

Adjusting the EHA does it change the lower chamber pressure?

If the reply is yes then I beleive the best way to check whether it is correctly adjusted is to connect two pressure gauge one on the upper chamber and one on the lower chamber (difference 0.4bars). Does any expert concurr with my assumptions/ conclusion?

The EHA controls the chamber pressure diference yes! It is used to make slight adjustments to keep lambda in the proper range. At WOT it gives more fuel flow basically! At idle and throughout the power band it will keep the mixture where it is supposed to be based on readings and interpretations from the O2 sensor and a Water Temp Sensor on the block!

Hi All:

First off, a Big Thank You to pesuazo, danwatt, cc260E and mctwin2kman for your followup replies.

My coolant level has been steady and the white smoke could be from the brand new muffler I installed.

I will be heading out to Sears or Radio Shack to pickup a multimeter to check duty cycle. Does anyone know how to check the duty cycle?

I will take a spare water temp sensor and change that. Is there anyway to check the O2 sensor? The O2 light doesn't come on at all except when I turn on the ignition key. That I believe is normal.

Once again, a big Thank You for all your help and if anyone else has ideas, please keep them coming.

Aloha,
Eric

On the face of the multimeter, there should be a setting for duty cycle readings you can dial into. On mine, you can measure it be frequency or by percent (you want percent). Now find the X11 diagnostic connector. Put the positive lead on pin 2 (ground) and the negative on pin 3 (data). Yes, it's supposed to be inversed. Turn the key all the way over, but do not start it. Something like 50% or 70% should show up on your multimeter (something to do with federal vs cali emissions?). With the car running, the duty cycle should be within 10% between idle and 2500rpm.

I'm pretty new at this, so this is as much as I understand. More experienced people should fill in the blanks.

Also, a pic if it helps:

http://dano.pocketrubbish.com/images...erdutycyle.jpg

Duty cycle should be %50 +-%5 for a %10 swing. To check the O2 sensor you can just find the wire under the floor mat. On the 190E it is under the passenger front floor mat. Just pierce the wire that is the actual signal wire, should be three, two are for the heater element. Using Multimeter measure DC voltage. Ground black lead and use red for the wire. You should see a voltage under 1V. .5V is normally what you would see roughly for a vehicle with the proper mixture setting's. Should swing around .3-.7 if I recall correctly.

Check the mixture on the X11 first since it will give a code if something is wrong. Such as no wandering and staying at %50 is normally a bad O2! Check Lambda on the X11 when the engine is at operating temp and has been running for a few minutes.

And as you can see from the reading in my picture, I've got some work to do!

This may help:

http://www.peachparts.com/Wikka/M103VacuumLeak

Update, Not Going So Well!
 

Hi All:

A Big Thank You to Dan, Jamie and Warren!

Here is an update. I went to Sears and purchased the same multi meter that Dan used in his picture. Lucky me, it was on sale for $25.00. I followed Dan's instructions and the meter read 69.3% before starting the car and when started it reads 49.5%. Is this telling me something is way out of tune since reading from the posts that is should be set at 50%.

No matter which way I turn the hex screw on the EHA, the setting doesn't change. Am I doing something wrong or and I barking up the wrong tree. Do I need to look at other things?

Please chime in if there is anything I am doing wrong or if I need to look at something different. All of your help is greatly appreciated and I Thank You Very Much!

Aloha,
Eric

1st - 49.5% is very close to 50%, just round it off. The 69.3% can be rounded to 70%, which indicates you have a US, non-California car.

2nd - The reading being steady at 50% would indicate a problem w/ your O2 sensor.

3rd - once the O2 sensor is fixed, you want to adjust the EHA/mixture so that it hovers near 50%; you won't get it exactly there, and it won't hold that either - you'll see the reading bounce around a fair amount.