My midlife crisis purchase; E86 BMW Z4 Coupe

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JakeT said:

Isn’t there a supply, and three loads? Why not disconnect the supply to make sure it’s fixed, and then re-add them to see what causes the fuse to blow.

Is the supply the bottom one? The top one is form the CCV, then the next two are the oil return pipe and the rocker cover to CCV.

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roadie said:

Crazy frustrating. Do you have any plans to delete the sound generator like I think you did with the 130i?

I think it’ll be staying!

It seems a bit different to the one in the 1 series cars which were fine if it was removed. This seems to crap it’s pants if it’s not connected properly.

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JakeT said:

I think they’re all wired in parallel so it doesn’t matter how they go together. I’d think about disconnecting them all in that case, or seeing which look to go to the inlet and which goes back to the engine wiring looks. I think you’re on the right track though!

The top one has to go to the oil separator block because it’s so short. That’s been unplugged and the light has still come on and I’m sure the fuse has blown again.

I’m going to try one at a time for now until which of the remaining three are causing me issues. I’m determined to dine out which of them it is (just as well I bought a big box of fuses ).

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Another blown fuse.

The oil separator block is plugged back in and the vent pipe from the back of the rocker cover is unplugged this time. Two culprits left after this one; oil return feed and the main power supply.

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d_a_n1979 said:

Hi Sam - do you want my 12 sledgehammer? Can send it next day delivery

It’s more likely a can of petrol and a box of matches!

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pmorg4 said:

Sounds like you're taking a methodical approach to finding the short. Don't rule out one of the lambda sensors, there are four of them and it's entirely possible that the heating circuit has failed in a way that causes a short. I don't know how easy they are to disconnect, and you'll certainly get an engine management light while it's disconnected, but you should at least be able to eliminate those as a cause of the short.

Worst case it might be that the short is in the wiring loom itself, if it's been rubbing and worn through, which would be tricky to trace. An easier option may be to remove the fuse and probe the "cold" side of the fuse (ie the side that is connected to the lambdas). It should be open circuit or at least high resistance through whatever's connected to it. If you're getting low resistance to ground, start disconnecting the circuits running from that fuse to see if the resistance suddenly jumps, which would indicate that you've found the fault circuit.

I'm doing my best to be methodical.

I've been focusing on the CCV side of the circuit because that is what I've changed / fiddled with.

Re the lamda sensors, the pre cat ones are easy to unplug because they're under the engine cover on top of the engine. The post cat ones can be got at easily but I'd need to jack the car up. I had no issues before replacing the CCV.

If there is a break in the loom, I'm guessing that it'll be the cable that supplies power to the heating elements and runs under the manifold. There are only two cales in a plastic sheath that run to the cable block that is connected to the side of the manifold.

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ess said:

More Z4 + SeaSucker adventures.

650 miles, mainly rainy motorway driving, to St Simon near Aurillac, France from the Ashdown Forest.
Dropped my mate (pictured) so he could cycle back to Blighty for fun....

Wasn't sure if would work with the 'double bubble' creases on the roof, but absolutely fine.

Hope you resolve the electrical gremlins !

S

Good effort that. I’ve not used mine on a motorway or for any long trips yet…I’m still learning to trust it.

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So, if done some more fiddling tonight….

One of the throttle body bolts was a tad loose which was probably leading to a slight vacuum leak. The idle still flutters a wee bit initially but less than it was.

I am however still going through fuses at a rate of knots. I’ve tried unplugging each of the four power connectors on the CCV individually and all together. I also tried unplugging the pre-cat O2 sensors since they were so easy to get at, but nope. The fuse still blows as soon as the engine is started but the management light doesn’t come on until it’s next started.

I’m guessing it’s looking more and more like a wiring fault somewhere on that circuit.

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cerb4.5lee said:

I'm sorry to hear how much of a headache it is giving you currently Sam. I hope that you get to the bottom of it as soon as you can.

Cheers Lee.

There are no obvious side effects other than the amber check engine light. Topping up the oil regularly is starting look like the better option; the joys of hindsight.

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cerb4.5lee said:

I'm going back years now, but I remember my XR4x4 being a pig at blowing fuses as well. Everytime I touched the electric window switch it blew a fuse, and it used to drive me mad everytime I went to grab a ticket in multi storey car parks for example!

Fecking cars eh?!

Indeed.

Just to top it off, the near side headlight washer has given up the ghost and emptied the contents of my washer bottle on my drive.

Used ones are super expensive, like almost the same as a new one which is £115. Mine are disabled so I don’t really want to pay that for a new one. I’ve ordered a water bottle for a car without headlight washers for now (£14 from eBay). That’ll stop the leak.

I was then further rewarded by not putting the cap on properly which has been lost today. The Z4 is definitely fighting me a bit at the mo.

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JakeT said:

Forking grim. As a last ditch before pulling the inlet I’d see if you can remove the positive and negative wires from the fuse box snd see if that solves your issue. I suppose it’s not out of the realms of possibility that you’ve pinched the wires, caused a dead short and it blows the fuse as soon as you put the ignition on.

That’s what I was thinking of doing. The two wires that provide power to the CCV are colour coded and I’ve kind of been able to figure out twice route.

There’s a really good auto electrician (well they get great reviews) so I’m tempted to give them a shout tomorrow. I’m starting to think that a wire has got damaged somewhere along the line and after 18 years and numerous heat cycles it wouldn’t really be a surprise.

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Whilst I’m still no further forward with the flutter at idle in cold start or with apparent electrical fault I went back to my happy place of cosmetic stuff.

The brace behind the grilles was in a really bad state and it bothered me. It’s apparently quite a common issue on Z4’s.





It’s held in with four T30 screws and I attempted to get them undone with the grilles removed however BMW used the sttest bolts with a very shallow head. Joy. Os it was off with the front bumper

Removing some of the many screws and fixings.



Bumper off revealing the manky brace.



With better access and my dagga dagga gun, the four bolts holding the brace in place were soon out. Old and new brace.



Because I’m a bit weird, I took the opportunity to clean behind the bumper because no matter how much I get in the gaps with detailing brushes, there’s always a layer of green filth that’s visible.



And cleaned.





After my headlight washer crapped themselves yesterday, I swapped the water bottle for one from a car without washers because it was st loads cheaper than replacing the washers which are turned off.

The used part absolutely stunk and was full of sludge and alga which was nuked with lots of Milton.





The redundant washer line was removed from the front bumper.

I’ve also removed the side reflectors and am painting them body colour. They were in horrible condition and like many Z4 parts are bloody expensive for what they are. Plus I think the reflectors look cack.

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Mr Tidy said:

The washer reservoirs and filters often seem to grow amazing amounts of algae. Getting rid of the pointless headlamp washers is definitely the way to go!

I never understood the side reflectors either - they look terrible. Thankfully Ms don't have them, so why do 3.0Sis?

Anyway good luck with the idle problem.

It was an impressive amount of crack in there but to be honest the one on my car wasn’t much better. Both filters were covered in black sludge too.

I have no idea why the EU cars got the side reflectors. The US needs them by law I think. They’d look so much better without them. Mine will blend in soon enough.

No luck on the idle flutter on the electrical issue so far. I think I’m going to pull the manifold once more just to check. It’s booked in with an Indy on the 9th and an auto electrician on 11th.

I also need to decide what to do about my fog lights. Up close they’re absolutely gone; the reflectors are nothing but rust and there is a cream cheese like substance behind the lenses. I think I’ll for blanking plates because I don’t really use them, new ones are bloody expensive and used ones will probably be shagged.

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Jhonno said:

No headlight washers with xenons is an MOT failure is it not?

Dunno. My 335i and 130i both passed MOT’s with them turned off.

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InitialDave said:

MOT manual section 4.1.6 does list inspection of headlamp washers, but carries the caveat of it being for vehicls after 01/09/2009, and it's a minor if they don't work on normal headlights, major for LED or HID.

So on a pre-2009 it's not technically an inspection criteria.

That’ll be why it’s not been an issue then; all of my cars with xenon’s have been pre ‘09.

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Mr Tidy said:

Mine had green algae on the pump filters before I cleaned them!

It does seem strange they fitted the side reflectors to EU cars when they were only required in the States.

Good luck getting the idle flutter sorted.

The foglights are a PITA. Used ones are probably a false economy as they'll go the same way, and despite the price new ones will eventually! Blanking plates are probably the best option. I really can't remember the last time I used front foglights anyway, which is lucky because Z4Ms don't have them!

I had read about pre-2009 cars not needing headlamp washers for the MOT before I disable mine and it has passed 3 MOTs like that. I probably need to disable them on my 330i before one starts leaking.

This was a black gunge that absolutely stunk. Bloody horrible. It’s all gone now courtesy of Milton.

I was poking around the engine bay with a torch last night and I noticed that under one of the hose connectors that runs under the manifold, there is oil vapour/ spray. I can’t quite work out if it is from the pipe connector or the right angle connector that the pipe connects to which is removable and sealed by an o-ring.

It’s around part 7 in the diagram below where I can see oil. I don’t recall it being oily before….




Looks like I’ll be pulling the manifold again….I’m getting quite good at it now.

Failing that, it’s booked in for a garage to look at it on 9th.

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I headed up to Kedleston Country House for a local car thing with a friend in his Caterham R400.

The Z4 was washed before and I fitted the painted side reflectors which still need polishing.





The colour match isn’t 100% but it cost £15 to do.

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Sticks. said:

Re your uneven idle, don't the air hoses have a reputation for leaks and cracks? Mine whistles at certain speeds, but runs OK. Sorry if you've already done that but I always think do the easiest/cheapest checks first.

Is that on an N52 powered car or the early M54 powered cars?

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Gallons Per Mile said:

Re your exploded diagram above; if oil's getting out then air can get in. You might have found the problem! Did you disturb that bit when you did the CCV?

Only to unplug the old hose and plug in a new one. The hise that looks like oil vapour can escape is this one.

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Gallons Per Mile said:

Yep, if that's not sealing properly you've got an air leak. That could well the the issue.

It’s the only connection that’s not been checked to be honest. It was a sod to remove and get back in place. I’ll pull the manifold one night this week (again) and have a poke around.