Questions and Answers

Nissan Laurel Hard Start When Cold Q. Vincent, I just bought a 1994 Nissan Laurel, RB20 engine, 130,000 kilometers with P/S, and A/C. I lived in a tropical country. My car has the following problems: Every morning, the car is hard to start cold. Need to start 5 or 6 times. Recently, I just changed the fuel filter, spark plugs, air filter, serviced the starter and also changed the engine coolant temperature sensor. Problem still repeat.

2. I recently found out that the thermostat in the engine has been taken out. Thus, the cooling fan is always running when the engine is running. Will there be a problem i.e. the fan will eventually fail or cause poor engine performance?
3. The driver car lock is also not working properly. Need to lock the car from outside the driver side. Cannot lock inside. Can you advise the problem?

I have spend a few hundreds buck already fixing things but to no avail. I need your advice.

Thank you,
Paul

A. Okay Paul, by the numbers.

1. What we need to do is determine what is missing when it won't start, fuel or spark. The next time it won't start pull a spark plug wire and connect it to an old spark plug. Lay it on a metal part of the engine so it has a good ground. Now crank the engine and see if there is a spark. If not, then we know it's an ignition problem.

   If you have spark, the next thing to do is pull a vacuum line off the intake manifold. Spray a good shot of carburetor cleaner directly into the intake. Reconnect the vacuum line and try to start the engine. if it starts and runs as long as the carburetor cleaner lasts, you have a fuel problem. Once we know this, we can go from there.

   Also, there are two temperature sensors, one for the temperature gauge and one for the computer.You may have replaced the wrong one.

2. The thermostat being removed would not cause the cooling fan to run all the time. If fact, it would probably not come on as much as if it had a thermostat.

   Cooling fan operation is controlled by the PCM based on the reading from the Engine Coolant Temperature Sensor (ECTS). So there may be a problem with the PCM.

   In light of these two problems, I would say that you did replace the wrong sensor or have a bad PCM.

3. As for the door lock, you will need to remove the door panel to see what is wrong. The linkage rod between the inside door lock and the latch mechanism probably fell off. There is a plastic clip that locks the rod to the lock lever. These often break over time. Once the door panel is off, it should be fairly obvious what is wrong.