Ron in SC

I figured out that my hot start problems and also rough idle when hot is caused by my cold start injector dumping fuel.

So the next question is the cold start injector defective or is there something else, i.e., a sensor that is telling it to do that that is the source of the problem?

With the electical connector on the cold start valve disconnected the car runs fine when warmed up. If I connect it the car immediately loads up and puffs black smoke.

bamberger_1

The cold start valve is controlled by several temperature sensors (amognst other things) if the probelm is not the main controller sending out wrong signals, either the CSV is gone or the sensors are bad. The sensors are on the top of the block on the rear end, it can be a twin type and one is in the air inlet duct. You can measure the resistor values but you need the reference temperatures (Ohm/F or Celsius). I had a problem with the twin sensor, which a short circuit due to broken wire insulation. On the repair CD you might find the values. I have sold mine (CD) with the car recently. The CSV can be checked. You pull it out, start the car with CSV electrically disconnected and stop the engine again. This is just to get pressure in fuel lines. If the valve drains fuel now it is defective, because it shall be closed when not powered. Then connect the 12V DC from the battery and the valve shall open and release the fuel pressure (it may be a bid messy, so place in a glass jar or so.)
If this test is okay, and the temperature sensors are ok, the CSV is still leaking fuel, it may still get a signal from the controller to open. If you have a circuit diagram you can follow the signal from the controller (behind the battery). As I said I sold my CD but maybe you or some else has it to help you, if necessary.

Ron in SC

The connector to the cold start valve is providing power to the cold start valve 100 percent of the time. So it looks like the injector is fine. I disconnected the connector and the car starts and runs fine.

I do need to figure out why voltage is being supplied by that connector all the time. I do have the CDs and Alldata DIY to I'll see what I can figure out based on what you indicated in your post.

I've tested the sensors with an ohm meter on my other 300 a TE wagon, so when the sedan cools off I'll check the sensor values in ohms and compare.

It sounds like some sort of controller is causing the voltage to be supplied to the connector all the time. Of course I need to figure out why it's doing that.

bamberger_1

It appears that the temperature sensor either has a broken wire or a short circuit, and delivers the signal to the controller. As I said I dont know which way the Ohm values go with increasing temperture. If it is the temp-sensor it delivers the signal "COLD" to open the valve to enrich the mixture.

Ron in SC

I check the resistance of the following sensors both hot and cold in both the 300E and the 300TE and the differences in the reading I got from the two different cars was not great.

I also put the electronic control unit from the TE in the E to see if that made a difference. It did not.

Finally I attached test light to positive of battery and then point of test light on ground wire for cold start injector valve. The light did not illuminate so I’m pretty sure that means there is no break in ground wire.

Not sure what to do next.

bamberger_1

What you need now is a wiring diagram. If the sensors seem to be ok, it may be the connection from there to the controller. Therefore you need the diagram to check if the sensor values are deliverd to the controller. If you swap the controllers between the cars w/o noticing any change it can obviously only be the connection, because both controllers deliver the same output to the CSV. the diagram would also show other possible "culprits". But as I said I sold my documentation with the cars recently. So there is nothing I can send to you in that respect.

j.wilhite

where is the cold start valve located
can i just disconnect i live in pheonix never really that cold
you see im too poor to fix and too hardheaded to sell

Ron in SC

I just disconnected mine and the car still starts just fine. It was quite cold this morning about 34 degrees and the car started no different than my 300TE wagon.

When you take the air filter housing off you will see it. It's the only other injector there that doesn't go straight into a cylinder.

j.wilhite

i will try this and see if my problem goes away i really enjoy this forum
my car has been a handfull since i bought it and this is the last anoying
problem in a line of many butt im learning quickly

bamberger_1

Hi friends of W124's,
there is one more check you can do Ron, since you have 2 cars of the same type. Try o swap the fuel relay. the CSV gets the ground from the main controller (pin 13) and the life wire from the fuel relay (pin 4) The fuel relay is located behind the battery to the plug of the main controller the print says 6Zyl.KVS 6.350 min or so. It does not say KLIMA this is the A/C relay just behind the fuel relay.
By the way I have found an older book with diagrams. If you send me your e-mail address I can send you some scans if you like.
The characteristic of the sensors are pretty much a straight line coming from -30degree C @ 25.000 Ohm going to 120degree C @ 100Ohm. At 20C cooling water temp. the resistance shall be 2200 to 2800 Ohm. At 80 C the resistance is 290 to 370 Ohm. You can take the twin sensor out for checking, it is not inside the coolant circuit
The thermo sensors are connected as follows: one of the twin type goes to pin 21 of the main controller, one goes to pin 1 of the ignition controller located on the driver side fendor. The air in sensor goes to Pin 11 of the main controller. The documents that I have are in German (a good practice for a real MB-fan :-)) If you like I can also send you the book I found. Just let me know.

j.wilhite

well im starting great, runs much better , no hesatation
totaly different car thanks for the tip i was about to give up
let me know what you find for cause of failure
my car is a 92 300e euro one previous owner brought car with him from germany after having a us conversion done a mb

kierankennedy

i was wondering if anyone can help me with the cold start problems that i am having with my 1990 mercedes 300 TE. I live in Ireland and I have this car in portugal where i have a holiday home. I travel to portugal at least 4 times a year on vacation. The car is always stored in a garage and the temperature never gets much below 15 celcius. Every time I arrive there which on average is about every 3 months I start the car from cold. The car starts first turn. After the car runs for about ten minutes it starts to idle very rough and just cuts out. The car will not start for about another hour. I believe that it is a problem with the Cold Start valve staying on longer than it should and flooding the engine. I was wondering what i should do first.

1. Disconnect the CSV .Will the car start at 15 degress celsuis without it.?

2. Replace the CSV valve.?

3. Replace the engine temperature control sensor ?

4.Replace the engine Coolant sensor.?

I would be very grateful for some help please. I do not have the knowledge or tools to test the OHMs etc. Once the car starts after drying out after flooding the car starts no problem and doesent miss a beat.

stewall5656

Hi all, I have an e class 320 cdi on 53 plate with 170k on clock,runs beautiful but i have a little vibrating at certain speeds,more so when fully loaded, some say cluth in gerabox probs, some say get a glycol test, i can sometimes smell water { like hot rusty water smell if you know what i mean} can anyone help