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Jeroen wrote: Fri May 08, 2026 11:30 pm Looking fabulous, still in love with these tail pipes! As for the problems, what brand of fuel pump did you fit?

I bought a Bosch fuel pumpe from Autodoc. Could be bad one I have. I think I have another Bosch pump somewhere, but that is a few years old, and has not been in use for 5 years time, and I think trying that one might not bet the best option.
Any other brands that could be recommended?

Autodoc has fuel pump from Ridex, Magneti Marelli, Hitachi, Era, Valeo, Meat & Doria, Quiton Hazell. Those brands doesn´t tell me much, besides Valeo, but that pump is 400 euro, and the Bosch is 100 euro

We've seen some issues with Bosch fuel pumps the past few years, pumps failing even after only a few months. Definitely under suspicion. Alternatives I'd trust and that are not $$$$: Magneti Marelli, Quiton Hazell.

Jeroen wrote: Sun May 10, 2026 12:19 am We've seen some issues with Bosch fuel pumps the past few years, pumps failing even after only a few months. Definitely under suspicion. Alternatives I'd trust and that are not $$$$: Magneti Marelli, Quiton Hazell.

I think I will try and replace the fuel pump with a new one. Can´t understand why the distributor or WUR should cause any issuses after 4000 km.
The pump is cheaper than replacing fuel distributor or WUR.
I´ve bought new Bosch parts which have failed, even before I´ve managed to run the car with it. I bought the idle controller new Bosch, made in France, that failed, it didn´t close. So Bosch is probably bad brand these days.

Thanks for the feedback Jeroen

You're welcome, it's amazing that a once so trusted brand is going down the drain, also not OEM manufacturer for many modern day BMW parts anymore. Fingers crossed the pump is the cause, keep us posted!

I found out why my car was leaking coolant.
My guess was that either the shaft on the pump had failed, or gasket was leaking, but when I finally got to the pump after taking of the timing cover, I found a bolt that was loose. When I installed the new head, I removed the old guide wheel to replace it with the timing belt, then I have loosen the wrong bolt

Lucky for me that the bolt didn´t go anywhere, but stayed there, else I would have been back to searching for a new engine

So I replaced the pump and gasket. Now it´s all good.

The extra work you don't want, but it could have been much worse. Solved now!

I´ve been having some issues with my car running rich. The system and controll pressure were checked with a kit I bought cheap some time ago. I first had all pressures at specs, but then I had them all wrong the day after. I couldn´t figure this out. I bought a new K-jet test kit, and then I found out my system pressure was within spec of 5bar, and my cold control pressure was abit off, 2 bar at 15 degrees celcius. This should have been around 1,5 bar. So I knocked the tap on the WUR in to reduce cold control pressure. Then it all went wrong, I managed to knock it too far in, and ended up at 0.6 bar.
So I had to open it, and knock it back, and do it again. I managed to land at about 1.6bar. I didn´t touch it anymore, because it´s easy to go too far.

The car is working ok, not great. It runs´s to rich at idle, and abit lean, not worring lean when crusing along in 90 km/t.
At full throttle the engine works great, and starts to come alive, and seems to enjoy the amount of fuel it gets.

But at low speed and low rpm with little throttle, the engines hesitates, not much, but anyoing to experience, when driving.
I´m not sure what I should be replacing to see if I can get this problem away. I have ordered a new calibrated WUR, as I feel it´s increases the pressure abit fast. It should take 2-3 minutes atleast from 15 degrees and 1,5 bar to full pressure of 3,8 bar at warm engine, but my WUR goes to full pressure in 1 - 1,5 minutte. And the engine hesitates abit when driving with cold engine.

WUR at 15 degrees celcius


Control pressure at 2.2bar at 15 degrees celcius


Knocked the tap on WUR too far in


WUR at correct pressure with warm engine.


Engine running and reving, to check that vacuum works.
https://photos.google.com/share/AF1QipO ... 1yMm04WEtB

Where's your CO at, warm and at idle? No vacuum leaks? Oil dipstick is a known suspect.

Jeroen wrote: Sun May 31, 2026 10:36 pm Where's your CO at, warm and at idle? No vacuum leaks? Oil dipstick is a known suspect.

The air/fuel mixture is meassured to be 8, which means it runs very rich on idle, and on minor load I have around 11-12.
I will replace my auxillary air valve to another used I have from purchasing left over from a local guy. I have tested it to be ok.
When I replace the aux air valve, I will check for leaks, but I don´t think I have that.
I will also block the fuel line going to cold start valve to see if that could be leaking fuel. It´s a pain to dismantle from the air intake manifold, so it´s easier to block the fuel line. To see if my air/fuel ratio is improving.
If there is a leak through the oil dipstick, then I can´t get a new one, as it´s out of stock.

Still searching for where the fault can be. It could also be that the fuel distributor is out of spec too. But I hope it isn´t, as it´s only be used for 4000 km after rebuild.

And adjusting the mixture on the fuel dizzy to lean it out a bit? TB adjusted correctly at idle (base position)?

Jeroen wrote: Fri Jun 05, 2026 11:46 pm And adjusting the mixture on the fuel dizzy to lean it out a bit? TB adjusted correctly at idle (base position)?

In my quest find out why my engine isn´t running properly, I deceided to take out the spark plugs.
Cylinder 1,3,5 and 6 looks like this.


And cylinder 2 and 4 looks like this.


Cyl 2 and 4 is probably running lean, and the rest is rich?
Could my fuel distributor be off on cylinder 2 and 4?

I´m going disconnect all the injectors, and connect 6 new injectors I have, and connect them to supply lines for injectors and meassure the volum going out, and see if cylinder 2 and 4 is off compared to the others.
Does this sound like a good plan?

Sounds good indeed, fingers crossed!

si...poi prova anche ad incrociare gli iniettori per vedere se vedi differenze....

Mixture 1,3,5,6 seems perfect.
Plugs/cylinders 2 and 4 look like they don't burn anything at all.

BertjeConti wrote: Wed Jun 10, 2026 9:01 am Mixture 1,3,5,6 seems perfect.
Plugs/cylinders 2 and 4 look like they don't burn anything at all.

So it either means that no fuel goes to cylinder 2 and 4, or very little. The engine works great when I put metal to the floor, and there is good acceleration. So those cylinders has to work somehow. Else I would have noticed that the engine runs on 4 cylinders only. Or?