PeachParts Mercedes-Benz Forum - View Single Post - Where's the Coolant Temp Sensor and how do I test it? '86 300E

mctwin2kman · #11 08-09-2006, 10:32 AM

Larry the CIS-E needs to hit 80C to be at operating temp and be stoic. SO if you are low then it thinks your engine is below 80C and thus enriching mixture to much. Replace that bad boy as it is only about $40-$50 part. See your system never thinks it gets to 80C to adjust fuel/air to the proper mix. It is thus making it rich to compensate for the colder engine. Thus wreaking havoc on a warm start and warm idle. You will be getting too much fuel when starting at that temp. The next point is 100C where it will lean a hair to attempt to cool the chamber and thus the engine.

Also Larry if you have the 4 prong one and KE-III jetronic which has the vacuum line going to the Ignition Controller on the wheel well then the sensor also control advance as well.