horsman_944

So.. I have a 1987 944s and when I start it when its cold, it runs very rough and will not stay running until it has warmed up. I have done new fuel filter, had pros clean the injectors, new pressure regulator, new fuel dampener, new plugs, wires, rotor, coil, cap.. What could be causing this?

konakat

Could just be that the idle is a bit too low and the engine would tolerate it when the weather was warmer. Another possibility is the DME temp sensor going bad.

car_slave

Make sure your throttle position sensor is set correctly. With the engine off - turn the throttle cam by hand. You should hear a a micro-switch click when it comes off the closed position.

PeteL

One more sensor to think about. Engine Temp sensor. All of my cold start/cold running problems have been associated with this one. Latest issue I had was not the sensor itself, but rather the wiring to the plug. I pulled the boot on the plug back and saw the leads were shorting out. Separated them and the problems (rough start/stalling when cold) all went away.

KevinGross

Check the engine temp sensor (as Pete suggests), and check for vacuum leaks. The latter can often close up as the engine warms, creating a situation only when cold.

carlosvmata

+1 on the DME Temp Sensor. It's an inexpensive part (<$20) and was able to replaced mine a few weeks ago and made a world of difference for my 86 951. I pulled the intake, replaced the gauge temp. sensor, and intake manifold gaskets at the same time. Also managed to inspect vacuum hoses.

PeteL

Be sure to check the wiring to the sensor too...It may be just that...these cars are getting old, and the insulation on wires gets brittle.