In Reply to: Likely sources for _intermittent_ idle problems? posted by Bruce P on August 25, 1999 at 15:28:06:
: Recently purchased '88 528e (145k miles) has intermittent hard start and idling problems. It is usually OK with great mileage and decent acceleration, but occasionally (1 time every 2 weeks or so) will be hard to start and will run very rough until warmed up. Sometimes will be OK after 2-3 restarts rather than wait to warm up. Have put in new plugs, rotor, cap, air & fuel filter; 1 tank of Techroline to clean injectors; cleaned ICV with carb cleaner; cleaned fuses.
: Shouldn't most hard start/idling problems be more consistent (vacuum leaks, bad pressure regulator, bad sensors, etc.)? Or are most of the problems encountered usually intermittent? Any ideas what to look for?
: Many thanks.
Check the following, which can cause hard starting: (You already seem to know about the ICV and Idle control module. the injectors, vacuum,etc.)
1. Fuel pump relay
2. Coolant or engine temperature sensor (It the resistance is off on these, it will tell the computer that the engine is either hot or cold when the opposite is true, thereby causing the wrong mixture of air and fuel)
3. Ignition wires and coil(happened to me once)
4. Fuel pressure regulator.