V12 Coolant Temperature Sensor question
#1
11-04-2008 | 10:00 AM
Thread Starter
|
Junior Member
Joined: Sep 2008
Posts: 18
V12 Coolant Temperature Sensor question
On my 1994 SL600 V-12, one bank of cylinders is running rich at idle, plugs are black. The driver's side bank is running fine. Engine has lots of power when my foot is in it. Runs slightly rough at idle, engine smells rich at idle.
The dealer I bought the car from said they had changed the engine out. The wiring harness must have been changed out. The dealer put on two brand new throttle actuators. The running rich bank has a Bosch rebuilt air flow meter, and a new O2 sensor. The code reader does not give any fault codes, both banks of cylinders are Code 1 which means no problems.
A friend suggested looking at the coolant temperature sensors, if one was lying and said the engine was cold, then the computer would tell it to run rich. This 120.981 engine has two sensors, one for each head, where the hot water comes out of the head and goes to the central mounted thermostat.
Here is what I found: Each sensor has 4 male pins, but nothing on the sensor to clock the connector.
Each connector has a flat spot to clock it only one way, but the mating sensor has no flat spot to clock it.
I can put the female connector on any which-a-ways, I can pull it off, rotate it another 90 degrees, and stick it back on, and keep doing that. There is nothing to clock that connector to the water temp sensor. The female connector has the 1,2,3,4 numbers for it's pins, but the sensor has no numbers by its male pins.
This does not seem right.When the engine was changed out, could they have put in an earlier or later engine which has a different temp sensor/connector mating arrangement? Why does a temp sensor need 4 pins? What would you do?
The dealer I bought the car from said they had changed the engine out. The wiring harness must have been changed out. The dealer put on two brand new throttle actuators. The running rich bank has a Bosch rebuilt air flow meter, and a new O2 sensor. The code reader does not give any fault codes, both banks of cylinders are Code 1 which means no problems.
A friend suggested looking at the coolant temperature sensors, if one was lying and said the engine was cold, then the computer would tell it to run rich. This 120.981 engine has two sensors, one for each head, where the hot water comes out of the head and goes to the central mounted thermostat.
Here is what I found: Each sensor has 4 male pins, but nothing on the sensor to clock the connector.
Each connector has a flat spot to clock it only one way, but the mating sensor has no flat spot to clock it.
I can put the female connector on any which-a-ways, I can pull it off, rotate it another 90 degrees, and stick it back on, and keep doing that. There is nothing to clock that connector to the water temp sensor. The female connector has the 1,2,3,4 numbers for it's pins, but the sensor has no numbers by its male pins.
This does not seem right.When the engine was changed out, could they have put in an earlier or later engine which has a different temp sensor/connector mating arrangement? Why does a temp sensor need 4 pins? What would you do?
Thread
Thread Starter
Forum
Replies
Last Post
builderdude
General Tech
1
09-16-2010 12:17 PM
justaride
Mercedes AMG Class
0
12-08-2007 01:59 PM
