[Prev][Next][Index][Thread]

E30 318i Nagging Engine Problem

My 85 318i (110K) has an intermittant running problem inwhich the engine
intermittantly bucks / misses while driving.  The problem usually occurs
on the comute home from work when the temperature is warmer. It almost never
occurs in the morning. Although the engine water temperature runs the same
regardless of outside temp.

Here's whats happening, while driving at any speed, the engine intermittantly
misses.  Once the missing starts, it can get so bad that I have to pull over
and stop. Popping the hood, I notice that all three relays (fuel pump, idle
speed control, and vacuum advance) are all chattering.  If I turn the ignition
off then on, the car immediately restarts and then usually runs fine. Sometimes
the missing continues. A second switch off and on of the key seems to clear
the problem.  The fuel pressure is fine, my inline gauge indicates stable
fuel pressure. I've replaced both the fuel filter and the fuel pump relay.
The result is no effect. I've checked all the ground locations on the car
by wiggling all the wires, connectors while running. Neither has any effect.
I,ve checked the connector at the control unit, all seems fine. I've checked
the temperature sending switch, sensor, and cold start sensor and they appear
normal.  
I think the injection control unit is acting up, but I wouldn't expect a
digital device to act intermittantly, some input into it is causing this
problem.

Any comments?
Chris Smith
email: cesmith@domain.elided