2008 335i 6MT Startup issues

[Fishayyy]

So I recently changed my oil to Motul x-cess 8100 5w-40 and I've been having a weird issue in the mornings when trying to start my car on my driveway. If I leave the car parked in my driveway in neutral all night, but try to start the car with the shifter in reverse then the car makes a noise that sounds like a fuel pump trying to prime and it fails to start. Seems like this only happens when I try to start my car after leaving it on my driveway overnight and the mornings aren't even cold (60F). The fix is simple enough, just start the car in neutral, but I wanted to see if anyone knows what's going on with my car or if they've experienced anything similar. Additional info is Redline MTL Tranny fluid and Motiv Twin Disc Clutch. Usually this only happens once and then it will starts fine but I'll see if I can get a video of it tomorrow.

[shushikiary]

To me it sounds like the clutch might not be fully disengaging.

[Fishayyy]

To me it sounds like the clutch might not be fully disengaging.

Thats what I thought but I put the pedal all the way to the floor and the engagement point is near the top of the pedals travel. That makes the most sense though.

[shushikiary]

I just had another thought. its possible that in reverse the backup lights turn on, and though they dont exactly pull a ton of current they do a little bit. If your battery is on the verge of dying, and the problem doesnt happen while starting in first gear for example, its possible maybe its just really struggling to put out enough current.

If that was the case though I'd think it would have trouble starting in the cold too. Worth a try to hook another batter up with jumpers and see if the problem goes away though.

[Fishayyy]

I just had another thought. its possible that in reverse the backup lights turn on, and though they dont exactly pull a ton of current they do a little bit. If your battery is on the verge of dying, and the problem doesnt happen while starting in first gear for example, its possible maybe its just really struggling to put out enough current.

If that was the case though I'd think it would have trouble starting in the cold too. Worth a try to hook another batter up with jumpers and see if the problem goes away though.

It shouldnt be the battery since I got a new one about a year ago but I could try that this weekend.

[V8Bait]

Deleted read this wrong. Annoying we can't delete things here.

[Fishayyy]

Deleted read this wrong. Annoying we can't delete things here.

It would be a nice feature but I think you have to be a vendor to get that kinda power

[Fishayyy]

Okay so now the noise I was talking about seems to have started happening even if I start it in neutral and left it in neutral. I dont know if the driveway is causing the oil to drain away from certain parts or if the gear oil in my transmission is too viscous. Another problem could be my spark plugs are on their way out, but whats weird to me is that it makes the weird clicking noise that sounds like a fuel pump priming/gears grinding then the next time I go to start it the car will start like normal. Any ideas?

[shushikiary]

My water pump would make a sound like that sometimes when it started, could also be the fuel pump, both of them do some start up when you unlock the car.

[Fishayyy]

My water pump would make a sound like that sometimes when it started, could also be the fuel pump, both of them do some start up when you unlock the car.

But does it ever cause your car to fail starting up? Because that's what happens to me. It'll fail once then the second try it starts up like there's no problem.

[Simmi15]

Are you getting any codes? I'm going through the exact same thing except my car struggles at 200 rpm at first then dies; starts right back up perfectly. I get misfire codes in bank 1,456. Stealership said it wasn't the HPFP and that its $2,700 for injectors. Changing all injectors to index 12 tomorrow by great local mechanic. Have you ever changed your injectors @Fishayyy?

[Fishayyy]

Are you getting any codes? I'm going through the exact same thing except my car struggles at 200 rpm at first then dies; starts right back up perfectly. I get misfire codes in bank 1,456. Stealership said it wasn't the HPFP and that its $2,700 for injectors. Changing all injectors to index 12 tomorrow by great local mechanic. Have you ever changed your injectors @Fishayyy?

I have not, but the guy who owned the car before me might have. I'd have to check the service logs he had.

[shushikiary]

On hot days I've had the HPFP back leak fuel where its then hard to start the first time you try to start it, but then starts the 2nd time, but its rare and only when REALLY hot out.

If you had a leaky injector it could cause some rough starts. The best way in my experience to find a leaking injector is to look at your AFR while crusing, then let your foot off the gas and watch the AFR on both banks, if one banks AFR doesnt go all the way to 265 then you know you have a leaky injector for sure.

[Fishayyy]

On hot days I've had the HPFP back leak fuel where its then hard to start the first time you try to start it, but then starts the 2nd time, but its rare and only when REALLY hot out.

If you had a leaky injector it could cause some rough starts. The best way in my experience to find a leaking injector is to look at your AFR while crusing, then let your foot off the gas and watch the AFR on both banks, if one banks AFR doesnt go all the way to 265 then you know you have a leaky injector for sure.

I'm starting to think it might be the injectors because from time to time when I'm at lights the idle will oscillate between 600 and 900 then settle back down after a little while and a few days ago when I was pulling onto the freeway I noticed that in 3rd and 4th gear I was having weird power hiccups where I would go WOT and the boost looked like it was building normally but the power would kick in randomly around 3-4k RPM.

[Fishayyy]

The only things I can think of that would be causing this problem is either the injectors, the spark plugs, or the vanos solenoids.

[Simmi15]

We are going through the same issues I believe. All the way down to the 600-900 rpm oscillation. I will let you know when I get my car back today or Monday if injectors solve the problem.

[Fishayyy]

We are going through the same issues I believe. All the way down to the 600-900 rpm oscillation. I will let you know when I get my car back today or Monday if injectors solve the problem.

Thanks man! I haven't been getting any codes just the problems I described but hopefully injectors is the answer...even though they cost the most lol

[Fishayyy]

We are going through the same issues I believe. All the way down to the 600-900 rpm oscillation. I will let you know when I get my car back today or Monday if injectors solve the problem.

Any updates?

[Simmi15]

Any updates?

Hey @Fishayyy,

Mechanic finished installing all injectors today and has gone on numerous test drives, he is happy to report that the car behaves in a completely better manner, idles at 600-700 perfectly with no subtle rpm hiccops anymore too. He wants to give me the car back at 10am tomorrow after he starts it in the morning to see if a cold start misfire reoccurs. I promise I'm not one to just post up promises and not finish through with those promises. But as of now my judgement puts it as problem solved, I will post tomorrow afternoon with final pricing to fix my problem as I don't see that much here on the forums, I want people to see the costs involved with these premium cars even if I pay my mechanic well he does a very good job everytime.

Thanks

[Fishayyy]

Hey @Fishayyy,

Mechanic finished installing all injectors today and has gone on numerous test drives, he is happy to report that the car behaves in a completely better manner, idles at 600-700 perfectly with no subtle rpm hiccops anymore too. He wants to give me the car back at 10am tomorrow after he starts it in the morning to see if a cold start misfire reoccurs. I promise I'm not one to just post up promises and not finish through with those promises. But as of now my judgement puts it as problem solved, I will post tomorrow afternoon with final pricing to fix my problem as I don't see that much here on the forums, I want people to see the costs involved with these premium cars even if I pay my mechanic well he does a very good job everytime.

Thanks

Thanks for reporting back! I'll probably end up replacing my injectors once I pay off my speeding ticket lol

[Simmi15]

Thanks for reporting back! I'll probably end up replacing my injectors once I pay off my speeding ticket lol

Your telling me... I'm at 2 this year...

working on the whole "pedal modulation" thing