MB96

please help. "check engine - engine electronic" is the message that i get on my message console.
washed my car and also washed the engine compartment. i listened to a friend and he told me it was safe to wash under the hood. so...i spray washed the engine while it was cool. then next day, the car still drive-able. but lack power. with the air-conditioning running, it rough idle at stop. Where do i begin to look or should i just bring it to the dealer. Thank you in advanced.

Mr. Vanos

A check-engine light is usually always an emmisions related problem. Normally it's a bad O2 sensor. Take it in to have it checked out.

MB96

where exactly is the location of the O2 sensor.

Mr. Vanos

The O2 and Lambda sensors (there's usually 2-3) are located either on the exhaust manifold or more likely on the catalytic converter. It unlikely that you washing the engine compartment caused the sensor to short out. It may be coincidence. My guess is something go triggered and the dealership just needs to reset the "check engine" light.

Kar don

Run the engine for about 30 min with the hood open and in the sun, i bet water got into the plug wires.

MB96

I found out that Autozone can run the code diagnostic for free. I called them up and sure enough they said they can do it for my car. I took my car there, and they brought out a hand held unit. They attached the unit to a connection (odbII) located below the steering column. The unit reads out error codes 300 and 301. He then looked it up in the computer and told me that cylinder #1 was mis-firing. I took the car home and remove all the wires and spark-plugs. The wires were wet and so were the plugs. i have not put them back yet but just let them air dry at the moment. I am also going to change to new spark-plugs. I learned a good lesson this time about water and electricity.
Thank you all for your thoughts and replies. This is a great forum.

Mr. Vanos

Hmm, interesting. Thanks for sharing that. Just for future reference, it's probably a better idea to steam clean the engine than apply direct water to it. Hopefully, drying out those plugs should solve the problem.

Arthur Dalton

All 104 engines should not be washed as the plugs are in a deep cavity in the head and once water gets in there, it can not escape.
The car has 3 coils on top of the plugs further complicating the problem. There are no plug wires on these 3 plugs and the boots between the coils and plugs have been a troublesome part.
When changing plugs , it is recommended to change these at the same time [ $7-8 each].
Make sure you only use Bosch F8DC4 Super Copper on 104 engines..
Plats skip like hell on this engine...

MB96

Thank you for the very insightful information Arthur. I m learning something from here everyday. well, i did put in new plugs (F8DC4) and the car is running like a champ. No more hesitation on the engine. But the check engine message is still on. How do i clear it?

Arthur Dalton

You can clear it by disconnecting the battery, but make sure you have radio code handy when you do.

The CE lamp can be triggered by the shorting of the plugs
cuz your ECU cuts fuel to the injectors when the ignition module detects a fault. This is transfered to the diagnostic module that
trips the CE lamp. [As you can see from the mis-fire codes detected in your car]
Any fault that can affect the emmision paremeters of system, be it fuel, ign., egr, air pump, etc. will trip the CE if it happens twice in 2 concurrent trips.
So the o2 sensor probability is nil..
There are 38 Ce codes and the proper diagnoses is to pull the codes and that will direct the tech to determinimg the fault/remedy...

MB96

Yup, removed the battery really worked. that is a very good trick. my car is now back in action. thank you everyone very much for helping..

SPIKES

I have just bought a 97 e320. test drove the car a week ago and the engine was smooth but felt a vibration at idle via steering. i have had 124 series and diagnosed it as bad engine mountings.

negotiated a deal and went for another test drive today. the engine stumbles badly at idle. the seller had washed the engine on sunday.
drove car home and took all coils and plugs out . only 1 plug was wet. put it back and disconnected the battery. started motor later and check engine light was off. seemed smooth... as i put car into gear the engine started stumblin and also a bit of backfiring.

how do i pull the codes to see what is wrong.????
the car did not shift 100% when i drove it the first time....could there by chance be a related transmission problem that puts car in limp mode???

HELP PLEASE

E-Klasse

For $50 you can get a code scanner off of Ebay and see what the codes are. Autozone will read your codes for free. You may still have bad plug or more. I replaced my plugs and wires after my engine got soaked. The boots that go over the plugs under the coils could be bad if they were under water too. They come off of the coils and can be replaced. Do you have Bosch Super Coppers F8DC4 plug installed. Other kinds of plugs don't work in the M104 engine. I was told to stay away too from Platinum plugs.

SPIKES

THANK YOU E-KLASSE
i pulled all plugs today and cleaned everything.
took for a drive much better and no check engine light but car will not pull smoothly. it feels very rough .
i wil try autozone and replace plugs.
will report back soon.

Air Marshall Eldritch

I just want to say, I think I learned more in this thread in 3 mins than I did all last week.
Good job guys.

Arthur Dalton, please post more often.

-rb

SPIKES

DITTO WHAT RB SAID

Arthur Dalton

<<the car did not shift 100% when i drove it the first time>>
The car has a Shift Delay when cold. This feature is to allow the cat to heat up fast to put the car into closed loop..
The delay should only be when cold and only delay the 2-3 shift point...
Normal

E-Klasse

Arthur is the KING... That's not to original sounding is it but it's true.

SPIKES

UPDATE
replaced plugs with bosch super copper. put it back and not much better. idling smooth (not lumpy) but vibration coming thru steering.

i replaced both engine mountings. vibration still the same.
the engine is smooth at idle but when you pull of it hesitates through out the range. (same sensation when a plug is wet and starts clearing it self)

- i am now not sure if it is the engine that is causing the vibration feel ????
- will the propshaft coupling have anything to do with it????
- i checked the resistance on the plug wires (3 only)and it is close to 2 ohm as indicted on rubber boot of plug fitting. how do i check the coils?
- B.T.W the check engine light has not come on since i cleaned the plugs and disconnected the battery so a code will not tell me where the problem is???

WOW IT HAS BEEN A LONG DAY.......CARS....CANT LIFE WITHOUT THEM!!!!!

P.S: i saw the manual mentioned the piece about the transmission changing differently while warming up...thanks ARTHUR

SPIKES

)))

Arthur Dalton

<i checked the resistance on the plug wires (3 only)and it is close to 2 ohm as indicted on rubber boot of plug fitting. >

The problem is not the resistance of the connector, rather the compression springs at the tip.
The connection at the others is a Snap connector and they do not fail... but the ones at the coils is a compession fitting of the spring on top of the plugs [ this has to be used as the coil is mounted on top of these 3 plugs]. Not a good set-up...
I recommend changing these to the newer style whenever anyone changes plugs. we di it automatically cuz of the fail rate..
They are only 7-8 ea...

SPIKES

thanks for the reply ARTHUR. after reading my post do you think my problem is with the plug wires and coils????

i am not sure if i understand you...should i replace the ends of the coils that go onto the plugs?
are the "plain wires" o.k?

thanks again..

Arthur Dalton

There are no plug wires on the plugs under each coil...only the plug boot connector [ that consist of the resistor,boot , and spring connector, - it is a single part ]
The high failure rate of these is that the heat is trapped at these 3 b/c of the coil on top, whereas the other 3 don't have this problem...[ being open to air]
That is what you replace ...
The reason the poor ilde/running when these fail is that on this type of ignition [ waste spark ignition] , the coil fires 2 plugs in
series with each other .. so one is firing on power stroke and the other is just a wasted spark... but because of the series connection between the 2, if there is a bad connection at either ,
then the skip can effect both cylinders....
Also of importance on these type of systems is to make sure the plug gap is not too wide b/c the coil has to bridge 2 gaps for the completed circuit [ in other words , a .040 gap is actually an .080 gap for the coil of that pair ...

And to complicate the overall running, the Engine Control
module is mapped to shut down the power to each individual injector when an ignition fault is detected at each plug..
So you can see why we just change them whenever doing plugs....

E-Klasse

I picked up a Bosch Premium Wire Set, part number 09386. It included the 3 boots that connect to the coils and 3 wires to go to the other 3 plugs. They are for the M104 engines, 2.8L and 3.2L.

SPIKES

GREAT EXPLANATION.....THANKS GUYS.

this replacement will be my next step and i will report back.

i saw a post about codes that can be pulled of a/c controls in dash.

i pulled them up and found that code 6 is engine water temp. code 24 is batt. voltage. i wanted to check this as i have also seen related posts about a bad battery not giving enough current that causes check engine light problems.

i am just curios as to what the other codes were???( a engine oil pressure and /or temp will be interesting).