98 SL Running Rich???
 

Here is a problem I have not been able to fix. My 98 SL is running rich on Starts only. Usually have to hold the throttle open to get it to start then after 30 seconds it idles normal. The MAP sensor was replaced, injectors tested fine, and fuel pump consistantly runs the correct pressure. Any suggestions??

have you replaced ECTS with brass style replacement?

I have not. How would this affect the fuel mixture?

Time for "chalk talk" ....

Engine Coolant Temperature Sensor - (ECTS) monitors the temperature of water exiting the engine. Its signal is sent to the Powertrain control Module - (PCM) where the computer reads the signal, and adjusts the fuel mixture ratio for maximum economy and efficiency. If the sensor is open, the PCM will think the engine is very cold, and adjust the settings accordingly. If the sensor is shorted, the PCM will think the engine is very hot, and adjust the settings that direction.

Use only brass-tipped OEM replacements for reliability. Replace the electrical connector on the wires at the same time. Use Teflon tape on the sensor threads to make the job easier, and work only on a cold engine, to avoid scalds/burns.

Material costs will be about $40usd ($15 for the sensor, and $25 for the connector).