Hi, I own a 1992 Mercedes-Benz CE300 (Recent purchase) and I am having a few issues with it.Its starts up, idles high and once you kick it down, rough ideals until it stall out. Sometimes wont start up right away but eventually starts. Someone told me a cold weather injector? Any ideas? I am ordered and am changing the over load protection relay and voltage regulator but any other ideas?

Do a search on low idle. My 92 wagon was doing the same thing when I got it. Hindsight, I'd start with an O2 sensor, the Ford version is $25, if you can solder or splice the wires ofg the Mercedes plug to it. Unplug the Idle Air Control Valve and see if it helps. If you smell fuel under the hood, check the Electro Hydraulic Actuator on the side of the injection unit. Next, start looking for vacuum leaks. The boot that connects the injection body to the intake manifold was not fully seated and created a HUGE vacuum leak. I also had three injectors sucking air past old dried out seals. A full set of injectors and seals is under $300, so it's not a huge expense or a difficult task to install fresh ones.

Look on youtube for videos on the CIS fuel injection system. It's like nothing else. Not terribly complicated, just real different. Once you understand it, troubleshooting will be a lot easier.

Detail OVP relay needs replacing because this part shows these problems up that you have .

OVP didn't do a thing for mine, which was acting almost identical, even after the big vac leak was fixed. If the ABS light isn't on, or it's not exhibiting any other OVP signs, I'd look elsewhere first. New EHA and getting that tuned in properly, then adjusting the fuel injection was the final fix for me. The O2 sensor helped, the injectors probably needed replacing, anyway. I put new idle control valve hoses on it, too. Nothing totally fixed the idle issue until I did the EHA. Took a while of taking it off, adjusting it, putting it back on, etc... but once I got it dialed in right, the car ran perfectly and has ever since.

Your symptoms indicate more than one possible issue. Slow to start could be a failed fuel accumulator... easy to test on the car and easy to change. Search for threads started by me for all the details including my destructive analysis with photos of the cracked diaphragm.

Mercedes advertised that if the "e" part of the KE system failed the engine would continue to operate. However, they failed to mention that all the cold start enhancements are in the e-part of the system, so if there's an issue on the e-side, cold starting can be very difficult.

The fuel pump should energize for about one second when you turn the ignition to the "On" position. Have a helper listen. Run the test multiple times to verify that the fuel pump relay is working consistently.

If everything is normal the engine should start and initially idle at about 1000-1200 in neutral depending on coolant temperature. You can't "kick it down" like an old carburetor with a mechanical auto chock since the cold idle speed is controlled by the e-part of the system based on engine coolant temperature, so check the coolant temperature sensors.

I don't think the cold start injector is energized below about 32F, so if you're cold starting above that it shouldn't be an issue.

As previously stated, if the OVP, which supplies power to both the KE and ABS controller is bad the ABS light will remain on after it starts up, so it's probably okay, and unless the system voltage is outside the range of 13.5-14.5 volts with the engine idling the regulator is likely okay.

The KE system is complicated and parts aren't cheap, so swapping out parts apriori can get expensive and time consuming... doing all the diagnostics you can to try to isolate the problem is a better way to go.

Duke

"*You can't "kick it down" like an old carburetor with a mechanical auto chock since the cold idle speed is controlled by the e-part of the system based on engine coolant temperature, so check the coolant temperature sensors."

Yup, and the idle is controlled by the Idle Control Valve (funny enough). Check the ICV hoses for cracks and give it a good cleaning, if it looks coked up and greasy on the inside. Mine acted weird until I unplugged the ICV with it running and then plugged it back in again. High and climbing idle quit.

The main E parts of the injection are the ICV, the EHA, and the O2 sensor, along with coolant temp, OAT and some others. From my experience chasing the idle problems on my car, those are the first three things to look at.