Slow start, slightly rough idle

[T1M]

Good luck man. What index injectors? -9's? How many miles on the car now?

[CarJunkie]

Originally Posted by T1M

Good luck man. What index injectors? -9's? How many miles on the car now?

Yup, I have -09 injectors, 43000 miles, problems began at about 38000. Symptoms improve, but do not fully resolve if I pour in a liter of fuel injector cleaner.

[hot-j]

I also had -9 injectors. Mine went bad around 37k. Weird.

[CarJunkie]

It's the HPFP. $1400.

[nachob]

Originally Posted by CarJunkie

It's the HPFP. $1400.

I know it hurts but must feel nice to finally know. Mine went out at 10k miles.

[analogue]

Unless you have definitive evidence for the HPFP, I would push pretty hard to get the injectors replaced first. They are covered under the warranty extension to 10yr/120k.

I had the same symptoms when my car was still under original warranty. The dealer replaced both the HPFP and LPFP and the problem was still there. They finally changed the injectors (which did not throw any codes) with index 11, and my car was fixed.

[ayao]

Originally Posted by CarJunkie

It's the HPFP. $1400.

There's an extended HPFP for a subset of N54 cars but I do not believe our 1Ms are included. Painful. Thanks for keeping us updated. Do you think a trusted indy could get it done for less than $1400 or is that about the going rate?

[flzrider]

Originally Posted by CarJunkie

It's the HPFP. $1400.

Originally Posted by analogue

Unless you have definitive evidence for the HPFP, I would push pretty hard to get the injectors replaced first. They are covered under the warranty extension to 10yr/120k.

I had the same symptoms when my car was still under original warranty. The dealer replaced both the HPFP and LPFP and the problem was still there. They finally changed the injectors (which did not throw any codes) with index 11, and my car was fixed.

I think I have to agree with analogue here. And if it is indeed the HPFP, I would push for warranty coverage seeing as how the N54 in our cars is identical to the one covered in the warranty extension, but for some reason the 1M was left out on the list.

Good luck and keep us up to date!

[CarJunkie]

I went ahead and had them change out the HPFP. The work is done, but the programming didn't finish by the end of the day, so I will get the car back tomorrow and update then.

[CarJunkie]

HPFP was replaced. Car ran poorly, and repeat testing indicated injectors needed to be replaced. That got done today also, under warranty. I am actually happy about that.


Here is the strange part. I had replaced all plugs and coils a month ago with BMW parts. After the injector install today, the car still ran poorly and they swapped out coils 1 at a time and found that coils 2 and 6 were bad. What's up with that? I have my receipt from ECS, so I won't be charged for the replacement coils, but I can't imagine that two coils could fail so quickly.

[nachob]

Originally Posted by CarJunkie

HPFP was replaced. Car ran poorly, and repeat testing indicated injectors needed to be replaced. That got done today also, under warranty. I am actually happy about that.


Here is the strange part. I had replaced all plugs and coils a month ago with BMW parts. After the injector install today, the car still ran poorly and they swapped out coils 1 at a time and found that coils 2 and 6 were bad. What's up with that? I have my receipt from ECS, so I won't be charged for the replacement coils, but I can't imagine that two coils could fail so quickly.

Argh. So you replaced fuel pump for nothing? Sorry it was injectors all along? Sorry man!!! : (

At least they didn't tell you to throw a new motor in it.

[CarJunkie]

Originally Posted by nachob

Argh. So you replaced fuel pump for nothing? Sorry it was injectors all along? Sorry man!!! : (

At least they didn't tell you to throw a new motor in it.

LOL, maybe. The fuel pump may have been part of the problem. It idles much better, throttle response much better, and I will know tomorrow how startup is.

This problem was developing as I completed my tune, so I am going to replace plugs, reset LVS and ECU learning, give it a week or so to learn, and shoot some logs to BuraQ to see if anything needs to be tweaked.

[CarJunkie]

All of the issues are resolved.

Startup is normal.
Smooth idle at any temp.
No cloud of exhaust when revving from idle.
No cloud of exhaust when going WOT.
No stumbliing at low RPM's when cold.
No misfires.
Calculated fuel economy is accurate again.
Lambda's promptly max out at 235.2 on the cobb gauges when coasting in gear.
Much better throttle response, especially at low rpm's.

My tune had some part throttle inconsistency that showed up, likely because the finishing touches were done when the injectors were going south. WOT performance and logs were still perfect. BuraQ took a stab at some timing updates for lower load situations and its 95% better with 1 revision. I'll send him some normal driving/cruising/moderate acceleration logs after some learning time for what should be the final adjustment and then low-power track version of the map.

Shout out to BuraQ for being awesome! He has gone above and beyond for my tune!

[Neiman Levenson]

I'm glad to hear you got the car running smooth again. The bright side of the story is that

1. Injectors were replaced
2. HPFP was replaced.
3. coils are now good.
4. Spark plugs were done recently like you said so they should be good.

that covers just about everything that could potentially make an N54 misfire/rough idle / shutter besides O2 sensors which shouldn't break the bank If in the future need to be replaced at some point.

The cool thing about a 1M is that the cost to have all that done, will likely be cancelled out of the equation just in resale value of the car alone. So congrats, you basically upgraded the reliability of your car drastically for free!!!!