New Bosch injectors on my 528 (fixed long battle with P0173)

[BMW540san]

Let's face it, depending what year is it, few more years and E39 is officially a classic car in US, 25 years old.
I've had my 528 for 15 years now and I took good care of it. But, age and 152k miles are taking their tool.

I've been chasing P0173 for about a year now. It seems to be somewhat common issue but my fix was somewhat uncommon.
Basically, my bank 2 fuel trim was running at around -10% (o2 sensor sensing rich mixture, computer cutting fuel) and in most cases it was vacuum leak.
I've done some tests and I couldn't find it so I replaced intake manifold gaskets, many vacuum lines, intake bellow boot and fuel pressure regulator (all original).

After some more reading I decided to check injectors and voila, #5 injector (bank 2) plastic injector parts were falling apart which apparently affected the spray.
I got all six Bosch injectors for a great price at FCP Euro ($52 each after 5% coupon) and CEL is gone and fuel trim is back to normal. It's around 3% now which is within normal limits.
I still miss 540 after 13 years of ownership but 03 M5 has filled the gap nicely. 528 is definitely car to keep.

Fuel trim before injectors replacement. Bank 2 was spiking over -10% at times. Typicaly, anything over 10% (- or +) will cause CEL eventually which it did in my case. Remember, even though it seems only injector #5 was the problem, each O2 sensor monitors single bank (3 cylinders) so it adjust fuel trim for all 3 cylinders.






If you look closely at injector on the right, you'll see piece of plastic missing. I'm no expert but I imagine the injector has those plastic stripes for a reason






New injectors have different design but same flow rate





Fuel trim back to normal






Few pics of old girl. She's still handsome and back being healthy













Preparing new beast for major surgery (just bought and assembled tranny jack):
Leaking diff input shaft and rear main. As most of you know to replace rear main: whole exhaust system, driveshaft, tranny and clutch has to be removed.
Since current clutch has 60k miles on it (it was replaced at 50k miles by PO, car now has 110k miles), I'm doing the following in order not to repeat labor and install my favorite upgrade:
New Luk clutch, new Luk flywheel, Supersprint headers, HJS cats, X pipe, all mnandrel bend SS T304 tubing, Supersprint mufflers which are already on car.
Plus complete new suspension front and rear: All new Lemforder arms, mounts etc... Bilstein HD struts and shocks.




Also, already added VDO oli pressure gauge




And, Spal fan (clutch fan delete)

[amancuso]

Thanks for sharing. I too had 540i, but now have 528i/M5 combo. 528i is def. a keeper as nothing nowadays drives like it. The M5 fills the HP side nicely though for those times you want a little oomph!

[philly98540]

Hey looks whos back in here. Whats up Z?

The broken pintle cap likely not the cause of too much fuel, likely sticky injectors staying open too long. Good fix to put in the new injectors anyway! Nice fix. Glad its working like new again. Car still looks good.

So, who's doing your new exhaust this time? You DIY'ing it? Sounds like your doing same type of deal as you did on the 540. I'd get the heavy duty HJS's for that beast if you can swing it. They have the tripple spiral winding and more emmision reduction. See HD here: https://www.hjs-motorsport.de/produc...ogy-check.html
The 90 95 0182's or the 90 95 0192's seem about right but sure are pricey. Best of luck on the project.

[BMW540san]

Thanks for sharing. I too had 540i, but now have 528i/M5 combo. 528i is def. a keeper as nothing nowadays drives like it. The M5 fills the HP side nicely though for those times you want a little oomph!

You probably know this but 528 handles better than M5. Being considerably lighter and having rack and pinion vs recir, ball, its handling is amazing.
To be fair, 528 has completely new suspension with Bilsten HD's while M5 is on stock suspension (not for long).

[BMW540san]

Nothing much, how are you?

You're probably right but at definitely not a good thing for stuff falling inside no matter how little.
Yes, pretty much the same like 540 but this time I'll do spot welding and my neighbor will weld for me.
You don't even have to ask, of course I went with HJS. I got very good deal on these and confirmed with HJS they wil support M5 power.
https://www.m5board.com/vbulletin/e3...pe-budget.html
https://www.hjs-motorsport.de/produc...catalysts.html
9095 0072
I've actually exchanged email with their main engineer and he claims its Euro 2/3 not Euro 1/2. Either way, he guarantees they'll support M5.
I got them both for $650 delivered.