Montego Blue E86 is Long Gone - Z4MC Diff Rebuild

[1536Z4]

BMW has no stock, and has discontinued the part so no new stock will be available.

So another part discontinued . I had the same issue with the rubber seals under the roof . Doesn`t look good for spares in the future . I wonder how many other parts they have discontinued ?

[lucasxdiniz]

BMW has no stock, and has discontinued the part so no new stock will be available.

So another part discontinued . I had the same issue with the rubber seals under the roof . Doesn`t look good for spares in the future . I wonder how many other parts they have discontinued ?

I'm guessing that a lot of parts were 'discontinued' in 2019, 10yrs after the last Coupes were made. Since then the stocks have been drying up.

[lucasxdiniz]

...After a lot of looking around, I found the fuel filter housing (in-tank) had a hairline crack and fuel was coming out. Not enough to drip on the floor, but enough that you could smell it. I put it down that it was probably due to me leaving the tank low during winter and disturbing the opposite side by cleaning it.

The problem is now that I cannot get a new part. BMW has no stock, and has discontinued the part so no new stock will be available...

I got the part from Quarry Motors. They have a reasonable return policy/warranty for a used part and the packaging was pretty good + pretty much delivered next day. Previously I said I probably caused the part to crack by cleaning it, but I no longer think I had anything to do with the part cracking. Once I removed the part from the car, I realised it was going to happen whether I touched it or not as the plastic is fairly thick and the crack had properly propagated.



I also ordered a new collar (mine was a bit rusty) and a new o-ring from BMW. Installing it was very straight forward; turns out I can drop the exhaust in less than half an hour and that's the hardest part of the job (if your tank is empty).



But such is my luck that I broke something else in the re-assembly process. Once I installed the filter in place and made all the connections up, I wanted to make sure there would be no leak, so I put 25ltrs of petrol into the tank. There was no leak, I was happy and proceeded to put most of the car together. Once the exhaust was in place, I started it up to bleed the cooling system and only at that point I noticed that my fuel gauge wasn't working... Many things went through my head in terms of what I could have damaged or installed incorrectly. I was most worried that while pushing the pipes/wiring/filter back into the tank I managed to damage the wiring inside the tank that relates to one of the fuel senders (best case scenario here would require taking the pump out of the tank to repair the wiring).

I could see on INPA that the instrument cluster was not getting any signal from the RHS fuel sender as the resistance read too high. Our fuel tanks have two fuel senders, the LHS is integrated into the tank and RHS into the fuel pump. At that point I knew I had a wiring problem somewhere but for the life of me I could not find the pin-outs for the connector that go into the tank, so I couldn't check if the resistance values made sense at the fuel filter (60Ω empty 350Ω full).



After two days of research/contemplating/dreading, I decided to just remove the filter again and check the wiring from the source. So I did that and, by far, the worst part was removing the fuel. You can't syphon more than maybe 5ltrs of fuel from the fuel tank even when following BMW's procedure (inserting 90cm of hose into the tank). I had to remove the fuel via the fuel filter opening which is possible as you can control how much fuel comes out by using the fuel filter as a bore seal.

Once I could see into the tank, I immediately saw what pinout corresponded to the RHS fuel level sender and with a multimeter I was able to check that the RHS fuel sender was working correctly by moving it by hand and seeing the resistance value change. For posteriority:



I traced the issue to be in the harness that connects to the connector above. However, it was the opposite end of the harness which I had not directly touched and as close to the connector as it could get - a bit odd!



Unsurprisingly, the 'adapter lead fuel pump' harness (#3) is no longer available from BMW and no one has stock. Since the wire break was so close to the connector, there was no way of repairing the wire on its own, and I didn't want to just solder two harnesses together and effectively delete the connectors, so I enlisted the help from one of the electrical graduates from work and he managed to change the connectors to DT connectors. Before and after:




As he de-pinned the original connectors, he found what happened. One of the crimp seals had failed and water got into the wire and corroded it; so minimal disturbing of the harness was enough to break the wire where it was corroded. You can see pin #3 still has the crimp inside of the connector and one can see what remains from the copper wire.



Definitely a lot of unexpected work on this one. But learnt a lot and didn't bodge the wiring, so an overall win.