Slow start, slightly rough idle

[CarJunkie]

I have been noticing that my engine idle is less smooth than it used to be, and am now getting a much less robust rev and growl on cold-startups. I had thought that maybe it is time for a walnut blast, but today the engine cranked for about 5-6 seconds before it finally started.

Now I am thinking HPFP. Any other thoughts?

[Karmic Man]

Most likely spark plugs are shot and need replacing...

Could be HPFP as well

[CarJunkie]

New plugs 5k miles ago, coils looked great.

[craina]

Injectors

[nachob]

Originally Posted by craina

Injectors

Possible! I hope it's that. This is my second 1M and it has less roar than my new ED. I just attributed it to the more polite Canadian version but maybe there is something that tones down the cold start roar. Can you let us know what you find out please! You taking to dealer?

[1mm2]

My money is on HPFP.

What's the mileage?

[1mm2]

Originally Posted by nachob

Possible! I hope it's that. This is my second 1M and it has less roar than my new ED. I just attributed it to the more polite Canadian version but maybe there is something that tones down the cold start roar. Can you let us know what you find out please! You taking to dealer?

Mine wakes up the block on start up.

Then again, I've never had another 1M to compare against...

[nachob]

Originally Posted by vocan

Mine wakes up the block on start up.

Then again, I've never had another 1M to compare against...

My first one did. Canadian one understated.

[1mm2]

Originally Posted by nachob

My first one did. Canadian one understated.

It's probably used to really cold starts...

[CarJunkie]

I have always had the cold start that wakes up the block, so to speak. Quick jump to about 1500-1700rpm, loud as hell, gradual reduction to about 1000 rpm, holds there for a minute or so, then the usual 600-700 rpm idle.

Now, it barely manages to hit 1000 rpm and does so quietly, stutters, and then holds at the 1000 rpms before gradually going down to normal idle which is slightly rough. Once yesterday if cranked for a long time before starting which has been one of the most common complaints leading to a HPFP diagnosis. It runs beautifully otherwise, and doesn't seem to be down on power. Interestingly, if I immediately shut it off after a cold start, then start it again, it does the usual roaring routine at 1500-1700 rpms. I think the HPFP bleeds off pressure over time, which is why the startup is only effected when it has sat for a while.

Injectors are a good thought, but that should be just one or two injectors (they wouldn't all fail at the same time) and I would expect misfires, codes and a CEL.

I have an appointment next Tuesday at my favorite local independent shop that does all Euro. I gave them a heads up on the possibility of HPFP, but they will look into other possibilities. I am going to have them scope the valves and walnut blast if needed.

If they do replace the HPFP, I am going to have them drop in an ER charge pipe for me since they have to R+R all that stuff anyway. At least that will be one thing off my DIY to-do list.

I'll report back next week.

[craina]

Originally Posted by CarJunkie

I have always had the cold start that wakes up the block, so to speak. Quick jump to about 1500-1700rpm, loud as hell, gradual reduction to about 1000 rpm, holds there for a minute or so, then the usual 600-700 rpm idle.

Now, it barely manages to hit 1000 rpm and does so quietly, stutters, and then holds at the 1000 rpms before gradually going down to normal idle which is slightly rough. Once yesterday if cranked for a long time before starting which has been one of the most common complaints leading to a HPFP diagnosis. It runs beautifully otherwise, and doesn't seem to be down on power. Interestingly, if I immediately shut it off after a cold start, then start it again, it does the usual roaring routine at 1500-1700 rpms. I think the HPFP bleeds off pressure over time, which is why the startup is only effected when it has sat for a while.

Injectors are a good thought, but that should be just one or two injectors (they wouldn't all fail at the same time) and I would expect misfires, codes and a CEL.

I have an appointment next Tuesday at my favorite local independent shop that does all Euro. I gave them a heads up on the possibility of HPFP, but they will look into other possibilities. I am going to have them scope the valves and walnut blast if needed.

If they do replace the HPFP, I am going to have them drop in an ER charge pipe for me since they have to R+R all that stuff anyway. At least that will be one thing off my DIY to-do list.

I'll report back next week.

I had the exact same symptoms on cold start. Extended cranks, weak startup, sputtering. I did not get a CEL (for this reason I did not check for codes) and the car did not feel to be down on power. My first thought was the HPFP as the culprit.

Turns out that the sputtering was actually the car misfiring. One of the injectors had gone bad and the dealer replaced them all under warranty.

[Dackelone]

Originally Posted by CarJunkie

New plugs 5k miles ago, coils looked great.

What kind of plugs did you use? Bought from a BMW dealer I hope ?

[Isaacata]

Just took mine in today for extended crank time after getting sparks and coils done for something else and it was injectors. Covered by BMW so all is good now.

[CarJunkie]

Well, it is sounding like it may be injectors afterall. Interesting. Thanks for the input! Surprised that it would not give a CEL if misfiring.

Spark plugs were done at the dealer before my 4year/48k maintenance was up.

I am now out of warranty, so I will take it to the indy shop. They are awesome and have properly sorted out cars that had been screwed up by the local dealer. I trust them completely and it will cost me half what the dealer would charge.

[CarJunkie]

Originally Posted by Isaacata

Just took mine in today for extended crank time after getting sparks and coils done for something else and it was injectors. Covered by BMW so all is good now.

Did they replace all or just the fouled ones?

Just looked up injectors . . . $285 each, OUCH!

[Dackelone]

Originally Posted by CarJunkie

Did they replace all or just the fouled ones?

IF one injector is bad... you should replace all three injectors on that bank. There are two banks of injectors.

[ayao]

Originally Posted by craina

I had the exact same symptoms on cold start. Extended cranks, weak startup, sputtering. I did not get a CEL (for this reason I did not check for codes) and the car did not feel to be down on power. My first thought was the HPFP as the culprit.

Turns out that the sputtering was actually the car misfiring. One of the injectors had gone bad and the dealer replaced them all under warranty.

Was this covered under the extended injector-specific warranty?

[CarJunkie]

Originally Posted by ayao

Was this covered under the extended injector-specific warranty?

I do not have an extended warranty.

Has BMW provided an extended warranty for injectors specifically? I know they did this for the N54 in other cars, but has anyone successfully had this covered under warranty for the N54T? If so, I should definitely stop by the dealer.

[ayao]

Look at the following thread - the key is the referenced BMW-RP.com website.
http://www.1addicts.com/forums/showt...1242946&page=2

[CarJunkie]

You rock.

I plugged in my VIN and it brings me to a reimbursement form for:

B-ELWR 2015 Fuel Injectors 10Y120M

I will contact the dealer tomorrow with this info and they may be able to get it done. Of course, if it is the HPFP I'll have to pay up.

[craina]

Originally Posted by ayao

Was this covered under the extended injector-specific warranty?

My car was still under factory warranty when I had the injectors replaced so I am assuming it was covered by the standard factory warranty. That said, my car is covered under the injector-specific warranty.

[ayao]

Originally Posted by CarJunkie

You rock.

I plugged in my VIN and it brings me to a reimbursement form for:

B-ELWR 2015 Fuel Injectors 10Y120M

I will contact the dealer tomorrow with this info and they may be able to get it done. Of course, if it is the HPFP I'll have to pay up.

Fingers crossed! I'm looking forward to hearing about the outcome because I suspect many of us will be crossing this bridge in the future ...