Welcome to Tech Talk, where our resident BMW tech Nick Owen answers all your pressing BMW technical questions, frustrations, and issues. Have a question for Nick? Email him at techtalk@roundel.org. Let’s get into it.
N52 Long Cranking Time
I have an ’09 328i E92 with sport package and 6MT now at 155,000 miles. I’ve owned it since new.
The car is stored for at least six months of the year to keep it out of the Michigan winters. For the last couple of springs, the car has exhibited long cranking upon start-up, but this has gone away after driving the car for a month or so. This year the issue does not seem to want to go away. The CEL is not on.
At first, I thought this was related to a fuel pressure regulator not keeping pressure in the system. However, the car usually starts up fine cold and the long crank situation almost always arises after the engine is allowed to fully warm up, then shut off and the car is left parked for an hour.
The internet forums seem to suggest this is due to leaky injector(s) that are allowing fuel to vaporize and cause the engine to not want to start immediately. Once the vaporized fuel has a chance to evaporate (such as cold start the next morning), then start up is fine.
Do you think leaky injector(s) could be at fault here? Does the fuel rail have a Schrader valve that I can hook up a fuel pressure gauge to monitor system pressure?
Wojciech Galecki
That symptom is not indicative of leaking injectors. It seems to me a drop in fuel pressure, probably from the fuel pump. You will need to measure fuel pressure to verify but I do not recall there being a Schrader valve on the injector rail for the N51 engine. However, the E9X N51 BMWs did have an issue with fuel pumps and EKPS modules going bad, starting at around 120 – 150,000 miles. There were other symptoms associated with this failure so it may be worth seeking professional assistance, but you need to start there and verify pressure is dropping when it shouldn’t.
Changing Oil Without a Dipstick
Nowhere in the online owner’s manual of my 2026 X3 30 does the engine’s oil capacity appear. And, as you know, there’s no dipstick on this and other newer BMW models because the company only wants its high-priced service departments to perform this rather mundane task. Can you find how many quarts this engine takes (with filter change) so if I ever decide to do an oil change myself (which I’ve done on many vehicles in the past), I can just drain what’s in the engine and then replace with the exact amount needed.
Glenn Lamb
With filter, the maximum capacity for the B48 engine is about 5.7 liters. For an oil change, I would add 5.0 liters then measure it via the iDrive menu and add accordingly. You will most likely end up putting in 5.5L for an oil change.
Front End Noise
My 2009 335i coupe with M Sport suspension has about 97,000 miles and I do my best to keep it maintained and running well. The car runs great and is a joy to drive.
The issue that has developed is very puzzling. When taking the car out of the garage and turning the wheels, there is a popping sound like a spring moving. It only happens during turns and when there is a load on the front wheels. If I try to recreate it on jack stands there is no noise. There is no drifting to one side or the other and the car is very smooth otherwise.
I have looked over the front struts thoroughly and checked the tightness of the bolts. The springs are sitting correctly in the rubber retainers and the spring support piece. There doesn’t seem to be any looseness in the front end and the shop that does my alignments has not mentioned anything. The bump stops are totally worn out but I wouldn’t suspect that this is causing the issue.
My guess is it might be that the strut mounts are binding causing the noise. Struts and mounts and other front suspension hardware were replaced at 45,000 miles. However, there doesn’t seem to be much play in the suspension when pushing on the front end.
Any insights you might have would be appreciated.
John Calabria
My 2008 335i does the exact same thing when pulling out of my driveway and hitting the brakes. Left front, every time. This is usually one of two things:
- Bad ball joint
- Brake pads shifting in caliper
This is common with the E6X model as well. You can try to lubricate the backside of the front brake pads and clean the sliding points to allow the pad to shift in the carrier easier. If you want to check ball joints, you’re going to need a big pair of channel locks in order to compress the ball joints to check for play.
My experience says this is most likely caused by the brake pads.
7 Series Transmission Issue
I’m struggling with a lovely 2009 750Li Individual composition with 95,000 miles. The auto trans, ZF6HP28 goes into malfunction/limp mode randomly. I have replaced all inner seals including ones above the mechatronics unit, new ZF6 fluid with correct refill procedure, fresh pan/filter, reset adaptations. The solenoids are original to the car as far as I can tell. My diagnostic tool shows 400 626 turbine speed sensor, short circuit to ground or open circuit (intermittent), and 400 431 ratio monitoring clutch D, ratio implausible (intermittent). Short of a new (expensive!) mechatronics unit, what do you suggest?
Dorian
It seems your issue is related to a faulty sensor in the transmission. I think this kit will rectify that. The only other real options are:
- Replace the mechatronics. The new one will need to be coded to the vehicle.
- Replace the transmission with a used unit and have the mechatronics coded to your BMW.
Mechatronics issues are not fun to chase and usually expensive. The 6HP was one of the last ones to have issues before the 8HP came out. Depending on how much you love this BMW (with an N63), it might be an opportunity to walk away from it. Just something to think about.