My midlife crisis purchase; E86 BMW Z4 Coupe

[Court_S]

My Z4 was in useful mode tonight.



I still find it amusing seeing a silly car doing practical things.

[Court_S]

d_a_n1979 said:

Looks good Sam; properly used

Cheers Dan. I still quite like see silly cars doing practical things.

[Court_S]

The little Z4 has be scratching my head a bit at the moment.

Last night I decided to change the CCV to see if that would reduce the current oil consumption. My drive isn’t covered in oil so as pointed out by GPM, it’s most likely getting burnt. I had a CCV kit in the garage which was originally intended for the 330i, but because my oil consumption is higher I take priority!

Getting ready to start removing covers etc.



Beauty covers off, airbox and intake pipes removed. Things are starting to get disconnected and I’m labelling the plugs / connections as I go to avoid missing something.





Son enough, the intake manifold was loose but getting the oil return pipe free was a pain because the insulation on the CCV blocked access to tyre squeeze clips.



With a bit of swearing, it was soon free so I could removed the intake manifold. What instantly stood out was how much cheg there was in the return pipe.





Old CCV ready for removal.



And removed, next to the new one.



New one booted into place with new gaskets on the manifold.



Then it was time to put it all back together.





I was feeling quite happy / smug at this point because I’d sorted a few little things that weren’t quite in the right place, I assume after the starter motor was replaced but this is where it all went wrong….I started the car and it sprung into life, spluttered and stalled. The engine management light came on. Tits. At this point the light was fading so I went inside for a beer.

I came back to it this morning, checking connections etc. The plug for the small DISA didn’t look like it was all the way home some out came the airbox and intake again. A bit of faffing with the red rubber seal and it was plugged in like it should be. I checked all of the other connections and started the car minus the airbox and it was fine. Peachy.

Patting myself on the back, I chucked in the intake, plugged in the MAF and then started rage car….spluttered and stalled. Unplugged the MAF and it started / idled OK.

On the face of it, it sees, like the MAF has died / got damaged but I don’t see how be it was safe in the airbox. My only other suspicion is the new oil return pipe because it was dead easy to disconnect it from the CCV but would a vacuum leak from there make the car stall?

I’ve spoken to my local Sytner and got a quite for an OE MAF…..£359 with discount! I definitely don’t want to start firing the parts cannon so am going to try the MAF from the 330i tonight to see if it runs with that. If not, I might clean out the old return pipes fit that and see what happens.

I’ve tried to read the codes by Carly is being a turd. It gets to 90% on the scanning and then freezes. I’ve removed and reinstalled the app but it’s still not working.

[Court_S]

d_a_n1979 said:

Some good work there Sam but that's a bugger about the starting and stalling!

I would have thought if it was the MAF it'd run but just not as smoothly as it should be

Wondering if it's more of a vac leak/running lean that's causing it...

It looks as faffy a job as the CCV is on the M54s; with them a lot of it's buried, so best way is intake mani off so you don't snap anything (and refresh the intake mani gaskets at the same time)!

Yeah, it’s really odd. I’ll try the 330 MAF and see if that works.

If not, I’m suspecting the oil return pipe from the CCV. I had a really battle to get it to seat properly on the sump and I’m not 100% convinced by the CCV connection. If the other MAF doesn’t work, I’ll try refitting the old return pipe and see if that solves it.

The manifold gaskets are all new.

[Court_S]

Gallons Per Mile said:

It's 100% an air leak. Probably something on the CCV pipework isn't quite home tight and sealed. Classic air leak symptoms.

I suspect it’s the return pipe.

The other two have clicked into place really nicely and are side to remove, but that return pipe….

I’m going to pop the old one back in and see if it works.

Any idea why it runs with the MAF unplugged?

[Court_S]

The old oil return pipe has been fitted and this snapped into place nicely and feels really firm.

But the act will still only start / run with the MAF unplugged. I’ve just checked the other CCV hose connections and they all seem good and solid.

My last resort to fix it has to be the MAF from the 330i.

[Court_S]

B'stard Child said:

Gasket fell out on the inlet manifold when it was being refitted would be my bet unless Sam stuck them in before fitment

I’ll have a quick look tonight. They’re a right fit though so I’d be surprised if one fell out.

[Court_S]

I can’t swap the MAF’s between the cars because despite what the various websites are telling me, the MAF’s are completely different.

The one in the 330i is really thin and only has two pins whereas the Z4 one is much fatter with five pins.

I’m still no further forward with the Z4 at the moment. I’m tempted to buy a new MAF and see what happens. I can’t see any leaks anywhere and all the connectors look good.

[Court_S]

JakeT said:

Can you smoke test the inlet? You can make one too. But like others have said it could be vac leak related.

I did think about trying that.

The fact that bit runs with the MAF disconnected is confusing me somewhat.

[Court_S]

InitialDave said:

With no signal it'll probably default to a safe baseline, then when you plug jn the MAF and it gets a bad signal it thinks is good, it all goes to st?

Is there any information available for bench testing the MAF, resistances or voltage across certain pins, anything like that?

Basically yeah.

I think the MAF can be tested with INPA or ISTA which I don’t have.

I’m tempted to buy a new own from ECP tomorrow just to see if that works. If that doesn’t work, looks like I’m taking the manifold off again tomorrow night.

[Court_S]

Still not really any further forward.

I spent a few hours poking around under the manifold this evening and I noticed that the vacuum line at the front of the manifold from the throttle body was quite easy to pull off whereas the other night it was a total bd to remove.



Off came the manifold (again) and the little vacuum line. Looking at the manifold, it can only clip in one way and with some effort I managed to get it seated fully.



Popped it all back together and it’ll runs, but rough as fk whereas yesterday it would stall almost instantly. I tried a new MAF but to no avail. I still can’t get Carly to finish a code read. I’ve fitted the OE hoses in case the Febi ones are a bit st. I’m tempted to stick the old CCV unit back in tomorrow to see what happens.

Very confused and cheesed off right now.

[Court_S]

d_a_n1979 said:

Bloody hell Sam What a faff this is turning out to be...

Do you think you may have disturbed some wiring somewhere and can't quite see it clearly?

God knows. That had crossed my mind.

Started to wish that I’d just lived it’s topping up the oil regularly.

[Court_S]

pmorg4 said:

The MAF is almost certainly a red herring as you've discovered. Most likely a vacuum leak, with the MAF connected it's fuelling based on the measure quantity of air and thus getting it wrong due to the leak after the MAF. With the MAF disconnected the ECU falls back onto a pre calculated map based on things like manifold absolute pressure, throttle position and RPM.

I had a very similar situation on my E46 330i years back, ran like a dog with the MAF plugged in, but perfectly smooth without it. Turned out it had a large tear in the intake boot that was very difficult to spot without removing it. Once that was sorted it ran perfectly on the original MAF.

Good luck getting it sorted. These faults can be a pig to trace, if you have access to a smoke tester it could make it a lot easier to find the culprit, although as you've just done some work it's almost certainly a hose or gasket not seating properly.

I’ve checked the boots etc that I’ve removed and they all look good.

Hopefully a mate can pop over later with a code reader which might shed some light on whats going on. I’ve checked my coil connections in case I’ve knocked one etc but they all seem OK. Definitely feeling at a bit of a loss right now especially given that it should have been an easy bit of work.

[Court_S]

So, new development….

I put the sound generator pipework in that comes off try air intake and it’s running fine. Idled smoother that’s pre-CCV change but I still have the engine management light on.

[Court_S]

Craikeybaby said:

Could the EML be a historic code. Have you tried clearing them?

My Carly app is being a dick. It reads the codes to 90% and then crashes so I’m not able to clear them.

But it is progress.

[Court_S]

pmorg4 said:

If it's running smoothly with the MAF plugged in then you've sorted the air leak. The engine management light will probably clear itself after a few cycles of it running well, it doesn't go off immediately when tripped by things like an air leak.

I’m hoping that’s the case. It was idling nicely this morning with everything plugged in. I just need to put a few brackets etc back in place then I’m going to take it for a quick drive (locally).

[Court_S]

Just been for a drive and it’s absolutely fine; pulls well, idles fine etc.

And just need to get the engine management light off. Hoping that clearing the codes will sort that bit. Does feel like I’m nearly there.

It was a vacuum leak that was causing the issue by the looks of it, it just wasn’t were I’d assume it was from and it looks like the car needs the sound generator box in place to run nicely.

Are the creator code readers any good? Was thinking about buying one given that Carly is hopeless for me.

[Court_S]

jasonrobertson86 said:

Sorry, if this is a repeat, but have you upgraded the brakes and was it worth it?

Only in the same that I’ve fitted ceramic brake pads to cut down on dust (which is well worth it).

I’m still running stock callipers and rotor sizes.

[Court_S]

jasonrobertson86 said:

Thanks, which brand?
I see quite a few opinions here: https://z4-forum.com/forum/viewtopic.php?t=98616

I’ve got ATE Powerdiscs on the front with normal ATE discs on the rear and ATE ceramic pads.

I’ve used ATE ceramic pads on a few cars now and can’t fault them to be honest.

[Court_S]

jasonrobertson86 said:

Perfect, thank you. Has suspension been done also? Sorry if this has all been covered? I have seen posts where people have moved to b12 or whatever and found it too harsh but the boggo shocks/springs are quite soft in IMO

Yes. The previous owner fitted B4 dampers with Eibach springs.

I think the B12 kit is quite harsh albeit my only experience is in a friends 125i on 17 inch wheels.

I’ve fitted Powerflex RTAB bushes and front ARB bushes.