Z3 Immobilised

[Nubodi Automotive]

Hi Ian

Ive had this exact problem twice on Z3's

On a 3.0 facelift it was the MAP sensor, bought a cheap replacement off ebay. Fixed it but only lasted 2 months. Bought a Bosch one, to my knowledge still going strong years later.

However as yours is the pre-facelift going by the type of immobiliser this is what happened. Start but not run. BMW technician said he thought it was the KWS II box,charged £125. Not that.

Had an auto locksmith came out and cut two new keys and got all the keys to match the ring and immobiliser, all talking the correct language to each other. Cost £150. Not that.

Towed the car to BMW Grosvenor in Reading (BMW specialist that the main dealers use when they cant fix an electrical problem). They had it 4 days and it turned out to be the camshaft sensor. Car will start but the computer does not know where the camshaft is positioned so cuts the fuel. Cost £462 (OUCH)
If that had not cured it the crankshaft sensor was next to be replaced as that would cause the same reaction.

Hope this helps

[IanA]

Originally Posted by Nubodi Automotive

...Ive had this exact problem twice on Z3's...

Many thanks for your perspective.
I've posted on a number of forums and checked with some ECU specialists but yours is the first reply with direct experience.
OBD is not throwing any codes to point to the cam sensor which has obviously confused the situation but they are a known problem.
Your advice about cheap replacements is well taken- I don't relish stripping the VANOS gear repeatedly for the sake
of a £30 difference between the oriental ones and the Bosch/Delphi/Bilstein equivalent. That experience is repeated on several BMW forums.
Thanks again.

One ECU option that does sound interesting came from EndTuning-
"I can delete the immobiliser, but that doesn't sound like the immobiliser to
me. You should have the M52TU engine, and they shouldn't fire up at all if the
immobiliser has gone out of sync. It's possible a throttle problem could
cause an issue like that, or maybe cam or crank sensor.
It is possible for me to read the stored codes on the ECU, so if you do want
to go down the un-immobilising route, I'd be able to look for codes.
Immobiliser deletes are £50, and they come with raised rev limiters and
there can be options like a harder cut limiter, over-run burble etc."

I like the sound of that last bit !!!

[Nubodi Automotive]

So he agrees with my experience.

Cam or crank does not show when plugged in with the non ODBII cars (yours) or the BMW dealer or specialist would have found it straight away.

I would not advise raising the rev limiter, its there for a reason. Modify the exhaust if you want the snap and crackle sound.

[IanA]

Originally Posted by Nubodi Automotive

...I would not advise raising the rev limiter, its there for a reason. Modify the exhaust if you want the snap and crackle sound.

Agreed. It was the "hard" limiter that appealed- they rev so easily.

My short exhaust crackles and pops nicely already but I love the character it adds to the car.