Mercedes-Benz Forum banner

1 - 20 of 21 Posts

·
Registered
'90 200E
Joined
·
11 Posts
Discussion Starter #1
Hello people, first of all I don't know whether this is the right place to open up this topic but seeing that it's about the W124's, I assumed that I'd post this here.


I have a 1990 200E, with the 4 cylinder M102 engine and have some problems with it.

First, it makes this weird noise, I'm thinking that it's because the belt yet it's just a little bit loose, it's mostly tight but here is a video just in case if anybody else has any idea where the noise is coming from.


Second, the engine has kind of a weird habit, upon first start it struggles to idle on a full stop, it's having hard time to set the idling rpm to 750 rpm and eventually stalls but when I start her up again it's rock solid on the stable operating rpm. I really couldn't figure out why, cleaned up the distributor, the idling valve is in good shape, my only suspect is the voltage (or was it the amperage?) of the EHA (?) valve.


Thanks to everyone who may help, good day, stay safe.
 

·
Registered
W124
Joined
·
5,179 Posts
I think this is as good a place as you can find although not many of us have M102. One major problem I see with your motor and very possibly related to your noise, is that the viscous fan is not moving at all. Is it my imagination or a bad video view? It looks like its just sitting there while the engine is running.
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,935 Posts
More people have M102's over at W201, but you will get good advice here. I do, many thanks to the regulars here.

EHA valve receives a DC current (from a regulated current source). You can measure it to see if that loop has an issue.
If you have a current meter, set it up and measure the current.
Here are some facts, see if your car is close enough:

(1) Ignition on engine not running, EHA current = +20mA
(2) While cranking, EHA current = +60mA
(3) Right After engine starts, at extreme cold engine (like 40F) EHA current will settle to ~+20mA - +40mA depending on the coolant temp, if above 50F, more like +15mA - +20mA.
(4) It will start dropping rather quickly to the regular 0mA (or whatever you have the lambda set at) within a minute or two as the coolant temp rises)
(5) It will be a steady current till the engine reaches operating temp at which point the ECU takes over and it will start oscillating +/- 1mA of wherever the steady state is.

If your emission system is doing something similar, then it is probably not the EHA control but rather something else related to idle control loop.

But I would first check the coolant temp sensor and make sure it's resistance is within spec. You will find the spec if you did a search on this site.

But there are other things to check like your electrical system voltage, OVP output voltage' etc.

BTW, with that engine, your idle when the engine is cold should first idle at 900-1000 rpm and then slowly go down to 750 rpm within 1-2 minutes.

So some investigative effort with a Digital Multimeter is in order.

And yes, I believe eagle-eye tuttebenne is correct, the fan appears to be not moving.

- Cheers!
 

·
Registered
'90 200E
Joined
·
11 Posts
Discussion Starter #4
Thank you all,

Yes the fan is not moving at first but I honestly didn't know that it should've been moving on the first start, my ignorance probably and I don't know what's wrong with it.

Other than that, thank you for the EHA voltage ranges, I'll check them out as soon as I get my hands on a current meter.

Then again I've did some research on the fuel pressure regulator issues and it seems that this may be the problem for my idling problem, yet nobody has yet explained to me how the engine works perfectly after it stalls...
 

·
Registered
1989 W124 260E
Joined
·
1,704 Posts
Another thing ,, one of the pullys as a fibre outer case that the belt runs on the fiber outer part comes away and spins on the pully doing nothing .
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,935 Posts
Thank you all,

Yes the fan is not moving at first but I honestly didn't know that it should've been moving on the first start, my ignorance probably and I don't know what's wrong with it.

Other than that, thank you for the EHA voltage ranges, I'll check them out as soon as I get my hands on a current meter.

Then again I've did some research on the fuel pressure regulator issues and it seems that this may be the problem for my idling problem, yet nobody has yet explained to me how the engine works perfectly after it stalls...
You're welcome. I only presented the EHA valve expected behavior because you questioned your system.

Reading your original post again, it appears you are just having some fuel pressure issues upon initial start.
If it is taking a little time to build the pressure, you would definitely have issues running and eventually stalling.

I would check the fuel system pressure and it's behavior first (before fiddling with EHA current measurements, though that is less intrusive)

Most likely, the second time you run the car after a stall the Fuel Pump is primed again and it builds additional pressure (without any flow on the other end because the car is not running yet).

How does it run after the second start? Any sign of struggling as you drive?
 

·
W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
Joined
·
12,758 Posts
The fan on the OP's car is electric. At least the one on my 2.3 cosworth is.

Sent from my XT1710-02 using Tapatalk
 

·
Registered
'90 200E
Joined
·
11 Posts
Discussion Starter #10
Thank you everyone, my problems are over shadowed by another new and massive problem.

Today I've took out all of the relays out (including the abs and the jetronic controllers) and cleaned them up externally then put them back in, at first it run just like before but then when I got on to a test drive it suddenly stalled while driving at about 3000 rpm.

It did this twice and the rpms rapidly dropped into a sudden stop.

I have some suspicions on the cause of the problem, maybe it is the firing system, the distributor cap or the rotor, I'll go check it tomorrow but I also think that this may also be caused by the fuel system which I don't know how the check whether it's bad or not.

Anyway, if the shop is open here where I live, I'll take the car to it and have it inspected, until then I'll try to fix the issue with your guidance.

PS: the car is automatic.
 

·
Registered
'90 200E
Joined
·
11 Posts
Discussion Starter #11
Alright, so now I'm really pissed off...

The engine won't crack, it's probably the battery (Which shows green on the indicator but I don't trust these) but there is a strange part to it as I'm not familiar with the dead battery situation and the process of it.

When I put the key in the ignition and turn it to the run position, everything seems normal, even the door light comes on when it's open, the gauge cluster is all working with all the lights but when I turn the key to start the engine it just dies off and I hear a click noise, I tried this many times and it keeps repeating itself every time I disconnect and reconnect the battery.

If that's the normal procedure and the sign of a dead battery then I'm perfectly fine but if it's something other, looks like I have a problem.

I checked the OVP relay, the fuse is okay, the connecting pins are okay, altough I'm not sure with the inside of it, I will try to test it if jumping the battery has no effect.

So there it is, three days of my W124's curse upon me...
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,935 Posts
Cetoman, seems you have multiple issues piling up. OVP will not cause a no crank, so put that aside for now.

If I were you I would disconnect the starter barrel connector by the firewall ( not sure where yours is but mine is close to the brake reservoir)

Jump the connection with a wire and measure the voltage as you crank. If there is no crank I assume that voltage will not be anywhere near 12V.
If you do not have voltage there (which I assume you do not) you will have to track down the electrical problem.

By the way, this is where one would connect an auxilary starter switch that short that connection to the battery + terminal.

This is how I crank the engine from under the hood.

You can try this and see if the car cranks.
If it does not, you have a ground problem or the battery is shot.
 

·
Registered
'90 200E
Joined
·
11 Posts
Discussion Starter #13
Cetoman, seems you have multiple issues piling up. OVP will not cause a no crank, so put that aside for now.

If I were you I would disconnect the starter barrel connector by the firewall ( not sure where yours is but mine is close to the brake reservoir)

Jump the connection with a wire and measure the voltage as you crank. If there is no crank I assume that voltage will not be anywhere near 12V.
If you do not have voltage there (which I assume you do not) you will have to track down the electrical problem.

By the way, this is where one would connect an auxilary starter switch that short that connection to the battery + terminal.

This is how I crank the engine from under the hood.

You can try this and see if the car cranks.
If it does not, you have a ground problem or the battery is shot.
Well since it's not the OVP, I'm kind of relieved.

And the problem is that it won't even crank as I've described, first thing in the morning (I'm not in the US, different time zones) I'll jump the battery with another car and if that fails to accomplish anything, I'll go and do as you've described, thank you.
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,935 Posts
If your interior lights are on, but when you crack they dim or go out, that is a sign you have weak battery or a weak, chassis ground connection.
If it does not go dim then there is something else with your starter circuitry. If so, I would start and see if the there is voltage at the barrel connector when you crank.
If there is, then a relay must be busted. I'm assuming there is a starter relay between that connector and the starter.

First things first though, check out the battery.

It sounds like you maybe 9 hours away from California....
 

·
Registered
'90 200E
Joined
·
11 Posts
Discussion Starter #15
If your interior lights are on, but when you crack they dim or go out, that is a sign you have weak battery or a weak, chassis ground connection.
If it does not go dim then there is something else with your starter circuitry. If so, I would start and see if the there is voltage at the barrel connector when you crank.
If there is, then a relay must be busted. I'm assuming there is a starter relay between that connector and the starter.

First things first though, check out the battery.

It sounds like you maybe 9 hours away from California....
Well that's exactly the case, lights are on, turn the key, sudden click noise and the lights are off.

I just tried to jump the battery but it also didn't work, same thing happened, first I'll change the battery because I suspect it's much older than I presumed (It's my grandpa's car, so that would be normal) yet if it's not the battery I'll go searching for something another.

And about the starter relay, I couldn't locate it, a document described it as behind the dashboard but I couldn't find it there, I don't have a clue.


And I'm 10 hours early than California.
 

·
Registered
1989 W124 260E
Joined
·
1,704 Posts
Do charge the battery first. Dont do anything else untill its fully charged . . While the battery is charging remove the relay from the alternatior , onlt two screws hold it in and check the length of the brushes . This can then be forgotten .And move on to other vital checks later . ..
 

·
Registered
W124
Joined
·
5,179 Posts
Simple things first. As others have mentioned, the battery and its connections are the single most important part of the car. Without a solid battery and clean connections you will get odd and confusing symptoms. So before you do anything, clean the connectors, charge the battery, have it load tested by a battery provider, and do not do anything else until you have done all three of these. A jump start is misleading because you could have bad connections at the battery. A charge is misleading because you might have a battery that fails the load test. Get all of this done first and don't waste effort doing anything else. Let us know the outcome.

One other thing, when you report back on the battery load test condition, just confirm that your car has a fuel injected motor.
 

·
Registered
'90 200E
Joined
·
11 Posts
Discussion Starter #18
Yeah, getting a new battery did the trick.
Also the rough idling and the stall after 3000 rpm problems are gone.
Gonna get the alternator checked out tomorrow anyway, I suspect it creates the whining sound.
 

·
Registered
W124
Joined
·
5,179 Posts
When forum member Sbaert harps on and on about voltage regulators and the myriad problems they cause, remember this thread. Dollars to donuts the OP's regulator is only on the positive side of 12v. all the time.

BUT. I would confirm what is going on with the fan. From what I have read, the electric fans are pushers and these motors came with a mix of electric or viscous clutch driven fan.
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,935 Posts
These cars all should have a USB charger/voltmeter in the cigarette lighters. Only costs $10.

IMG_2718.JPG
 
1 - 20 of 21 Posts
Top