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Discussion Starter · #1 · (Edited)
Hey , I have a 1997 z3 with m44 engine - 60.000 miles on it.
The engine runs rough and idle is bad but,

what scares me the most is how the car occasionally will loose all power and the speedometer will go crazy for like 1 sec and then go back to normal.

((The car had a ruined KN cone air intake filter, I have replaced the filter but waiting for new MAF sensor(already ordered) , would the other sensor , which I think is Air intake temperature sensor come to any harm ?. ( but this is not my main issue) ))

This happens randomly , but for example when I drive upp hill , over a long speed bump or such it tends to happen.

Today I was driving uphill and then the car would start to behave, loosing power, speedometer maxing out, and eventually the car died on me. So I pulled over and tried for a while to get it going, it would crank but would not start , nothing worked. So I pulled it to my garage.

A friend brought his diagnostic tool and we read the fault codes , blank , no fault codes were present.

just for the kicks i tried to start it ,, and what not .. car starts and runs " normal" (rough )...

So ... the ghost messing with my car.. and I do not know what to do expect to hope from support here.

Normally the car runs fine , begins to even out the rough idle when hot and no lacking in power.

I haven't had the car for long and It sorta is a Electrical nightmare I am trying to sort it out.
I dont know if its a factor but , If i turn the key in a reverse circle when in ignition I can turn it endlessly , but it works normally when used to start the engine.

what I have done or changed so far:

  • spark plugs
    new KN air filter
    changed valve cover gasket

The problem persisted before these changes and still does.:cry:

my current idea for faults are:
Crankshaft position sensor?
Camshaft position sensor?
something electrical or they key?

If you have any questions or procedures that might help, ill try to respond asap.

Best regards.

D'oh, You Kids!
1984 633CSi, 1985 635CSi, 1985 325e, 1987 325is, 1993 325is, 1995 318is, 1995 M3, 2003 F150
31,075 Posts
They're a pain to get to, but you can test the crank and cam position sensors by unplugging them from under the intake manifold and use a DMM to check the resistance between the pins. The center pin to one of the outer pins will show no continuity (infinite resistance), and the center to the other pin should be in the neighborhood of 1250 ohms. If either one is very far off (more than plus or minus 10%) from that figure, it should be replaced.

14 Posts
Discussion Starter · #3 ·
Hi - Update :
Talked to previous owners ( o2 sensors are new - camshaft positions sensor are new ) known problem that the DEM was not getting power -went through all the wiring and re secured the connectors on the battery polars.

But now the new question is:
I tried to start the car today and it would crank but not start - ( sometimes it started for half a second and then died) , checked for ignition spark - no ignition spark!

tried again after some time -- car starts fine and runs normal...

I think this must be narrowing it all down to they ignition key ! I can spin the key counterclockwise endless , but it grabs and starts normal when turned right .
Can the immobilizer or something key related be ****ing with my system ?

any one who knows something ? , I would love some opinions.
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