Mercedes-Benz Forum banner

1 - 7 of 7 Posts

·
Registered
Mercedes 190E 2.0L - 1986(black with grey)
Joined
·
241 Posts
Discussion Starter #1
Hi all!
I have seen arround very much problems with the cold start on 190E.
I had a simillar problem. Here is the steps i've followed:
1. Check Fuel pump relay - condition good
2. Check distributor cap and rotor - condition good
3. Check temp sensor - condition good
4. Check cold start valve - condition good
5. Check wire betwen Cold start valve and fuel pump relay - good
6. Check ground wire of Cold start valve - good
7. Check fuse on OVP relay - good
Ffrom this point on there was only one thing left
8. Check OVP relay - bad
I have actually repaired the OVP relay. Inside the relay there was a bad track on the PCB. One signal of the actual relay coil was exfoliated. Repaired with some solder alloy.
Everything works fine now.
Hope this helps somebody.
 

·
Registered
2001 ML55
Joined
·
42 Posts
Great find. Maybe a write up on how you fixed the relay in more detail would be really good. I know I would really appreciate it.
 

·
Registered
Mercedes 190E 2.0L - 1986(black with grey)
Joined
·
241 Posts
Discussion Starter #3
One track on the PCB that leads to the coil of the electromagnetic relay inside the OVP was interrupted for some reason. In that way the relay coil was not supplied with any voltage, and therefore the relay contacts ware always open(the COLD START VALVE it was not supplied with electrical energy).

First of all I have take out the alluminium enclosure of the OVP.

I have scratched the green mask arround that terminal with a knive and after that with a soldering iron and some solder alloy I have rebuild the track(2-3 minutes of work after one month of diagnose:) ). It's kinda grose but it works.

After that I have not connected back the Cold Start Valve but instead just measured the voltage on the connector.
The engine it was not completly cold and I have measured arround 2-3V. The real challenge was in the morning when unbelieveble the engine has started from the first key. A little noisy but after a few seconds was going IDLE. Next morning the same...
I'm realy sorry that I cannot suply you with any picture but I will try tomorow.

P.S.: sorry for bad english
 

·
Registered
Joined
·
3 Posts
Hi Tavioman,

Very interesting topic you got there although it has been long time ago but i found it very useful since i faced the problem 1 week ago.

Can you please tell me how did you test the temp sensor?

Mine has a 4 pin

Thanks in advance bro
 

·
W201 Moderator
89 190E2.6- 5-speed Manual, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
2,622 Posts
abusweid1, not sure how taviorman checked his but here is how you check it:

Measure the terminals diagonally like this:

1 2

3 4

resistors are between 1 -4 and 2 -3. Both resistances should be about equal (not exact) and match the table below:

Temperature °C........Resistance kΩ
-20........................15.7
-10.........................9.2
0............................5.9
10...........................3.7
20...........................2.5
30...........................1.7
40...........................1.18
50...........................0.84
60...........................0.60
70...........................0.435
80...........................0.325
90...........................0.247

Taivorman, the OVP's do not last forever, it is great you could fix yours for the time being but they only last 10-15 years before they start having intermittent issues that are very difficult to diagnose.
So it is generally best to just replace them if really old. The date code will be on the side. So if you start seeing strange stalls, etc. just replace it with a KAE brand in the future.

- Cheers!
 

·
Registered
Joined
·
3 Posts
Dear dolucasi,

I tested the temp sensor and got the readings probably within the range since i made the test in freeze water and heated it until 80 degrees and the resistance showed as listed.

I moved on to everything else and figured out that the OVP does not catch unless I shake it a bit.

Opened the housing and saw what was listed in Tavioman post.

I cleaned the terminals on the green board and the contacts of the electromagnetic coil.

And it started to catch and the ICV started clicking as before, the baby now fires up immediately.

Seems the OVP has to be changed as you indicated.

Thanks a lot bro for the support (y)
 
1 - 7 of 7 Posts
Top