Mitsubishi Repair: Stalls at traffic lights, mitsubishi eclipse, tps sensor

Question
Dear Anthony,
    Thank you very much for your response and it has been quite helpful. After changing the spark plugs and spark plug wires, the car has NOT stall for last couple of days. But, still occasionally, I was not able to start the car (without stepping on the gas paddle).

To be more exact, I have done the following after reading your advice:
It is a 1995 Mitsubishi Eclipse, 2.0L non-turbo, fuel injection car. The problem happens occasionally. Typically, I do not step on the gas paddle when I start the car. Most of the time (95%) it starts fine and runs o.k.
Occasionally, the engine turns and fires up, but was not able to continue. Repeated starting like 4-6 times would still not able to get the engine to start up properly.
However, if I step on the gas paddle down to the floor, it would start up properly.
I have done the following:
- Changed PCV valve
- Checked and change some hoses
- Put in fuel injector cleaner, carburetor cleaner into the gas tank
- Took out the throttle body and clean (with carburetor cleaner) the throttle plate, air by-pass thoroughly
- Measured the IAC motor, and it is within specification
- Measured the TPS sensor, and it is within specification, and it moves smoothly between fully on and fully off.
- Unable to find the BISS (base idle setting screw) to adjust the idle speed
- Changed new set of spark plugs
- Changed new set of spark plug (distributor) wires
- The timing belt has been changed about 2 years ago.

I like to able to start the engine without needing to step on the gas paddle down to the floor.
Any suggestion as to what may be the problem(s), and what to check ?
Thank you very much,
Rookie.



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Followup To
Question -
I have a 1995 Eclipse, 2.0L non-turbo, fuel injection. The car occassionally stalls at traffic lights, the idling seems low and not very smooth.
I have checked all the vaccum hoses. Took out the throttle body, and cleaned thoroughly the throttle plate, idle air bypass, EGR pipe.
Problem still remains.
Any suggestions how and what to check ?
Thanks very much,
Rookie.
Answer -
Rookie,
If you have a service manual, go to the section that describes how to check the Idle Air Control (IAC) motor and the Throttle Posistion Sensor (TPS).  The IAC motor is also referred to as the Idle Speed Control (ISC) motor.  That motor is resposible for keeping your idling at a constant RPM when you car is at a stop.  Your TPS is responsible for letting your car's computer (ECU) know how far the throttle plate is open.  Your ECU uses this information to tell your fuel pressure regulator and injectors how much fuel to put in your engine.  If you find that either your TPS or IAC is malfunctioning, replace them.  Along those lines, also check your Base Idle Setting Screw (BISS).  It's located at the top of your throttlebody.  If your idle is set too low, and the BISS is in too tightly, your idle will be too low and could stall.  Check the service manual on the proper way to set the idle.  It's pretty easy.  Your PCV valve should be replace as well if you haven't replaced it in over a year.  They are cheap, easy to find (any auto store should have them), and can take less time to install then pumping a full tank of gas.

The last thing I can think of is that your timing belt may be off a bit.  If you haven't gotten your belt replaced in the last 60,000 miles or so, this would probably be a good time to replace it.  If your belt is starting to slip some teeth on your camshaft sprockets, it may completely slip off while driving some day.  If that happens, you'd be looking at about $1800 in rebuild costs.
Good luck!


Answer
Rookie,
The BISS is located on the top of the throttle body.  It may be covered with a round rubber cap or caulk-like material.  Just pry of the circular rubber cap to reveil the BISS.  There are instructions in any service manual to set the idle.

Another possibility could be your car's computer.  Read this article for further information:
http://90gsx.com/eclipse/cap/caps.htm

Though you have a '95 Eclipse, it may have been produced in late '94, which could fall into the category of faulty capacitors.  Pull out your ECU and check it for damage.  If there is damage it will be plainly noticable.
Good luck!