1998 z3 roadster starting problems

[_Mqx_]

Hi team

Bought a 1998 z3 with the 1.9L m44 engine here in Brisbane a few weeks ago, fuel pump was totally dead.

Replaced the following today:

- new fuel pump
- new fuel filter
- new spark plugs
- replaced fuel pump relay with known good working one but not new.

I have tested spark to all cylinders as well as injector pulse to all cylinders. Working as expected.

Here's the weird part. The car runs great with 3/4 ignition coils plugged in. With the 4th one plugged in, the car will not run.

We have 12v to fuel pump and relay but I am confused on what could cause this. I may try a new battery but otherwise out of ideas.

Thanks all.

 

[ExMX5owner]

Welcome aboard.

 

[DavidM]

It may be useful to check if any vacuum / air intake hoses are split / pitted / worn through?

 

[NZ00Z3]

Welcome to the forum from over the ditch in New Zealand.

As the problem occurs when you plug the last coil to the spark plug, it looks like a failed coil pack, Replace the coil pack.

The 4 in 1 M44 coil pack can be very expensive. See if a junk yard has one to try.

The alternative, if you are DIY handy, is to convert the engine to coil over plugs. See attached file.

 

[Stevo7682]

Hi and welcome from me in Scotland .

Yes would have to agree my first thought was the coil pack.
Stephen.

 

[_Mqx_]

Thanks team,

Going to search for a new coil pack and try that then report back.

Thanks very much.

 

[_Mqx_]

It may be useful to check if any vacuum / air intake hoses are split / pitted / worn through?

Checked but nothing I can see, knowing my luck it will be somewhere out of sight that I don't know about.