BimmerFest BMW Forum banner

X1 down for hessitation on hard acceleration

6K views 17 replies 7 participants last post by  eric9610 
#1 ·
my N20 X1 started to hessitate more and more after about 3000 miles. While I was on a 400mi road trip it stuttered so bad that the engine went into limp mode and would not let me shift above 6th gear. The Service Engine Light was flashing, so I had to stop and resstart the car. After restarting it seemed to run fine until I demanded more from the engine. It did this repeatedly so I had to turn the car into service at a local dealer while on my trip.

Based on the codes, they only adjusted the fuel trim and said it road tested fine. The problem persists and I drove the car home conservatively.

It's back at the dealer now and they've had it for 3 days. Not sure what's going on... Anyone else experience anything similar? I'll keep you posted on what the fix was.

The only good thing to come out of this a lots of courtesy car time in an F30 for comparison, which I will post on another thread for those who are deciding btwn the X1 and the F30.
 
#2 ·
Hmm, I haven't heard about this on the N20, HPFP? (Just kidding, I hope, that issue was suppose to be a thing of the past with a newer part design)

It's been a couple a month or so since I dug hard into researching the N20 and current problems reported (Didn't ever see anything like this reported anywhere) but doing some reading up on the other model forums that also use the N20 wouldn't be a bad idea to see if anyone has posted the same issues there in the last month.

I don't understand the fuel trim though. Where were you driving? Any place abnormal for temperature or elevation? My wife had an A3 that always had the turbo shutting down randomly when we drove in Phoenix in the summer -- Great dealership there, offered to bring in a tech and solve it on a Saturday at 6:00PM but said it would go away 50 miles outside, it did, and only returned when were in that area.
 
#3 ·
No, it occurs everywhere, even 400 miles apart at high and low elevations, ambient temp was moderate at about 50F. I noticed it way back, maybe from new since I drove it easy to begin with but for sure it got worse. This is the their second attempt. If they can't fix in three attempts, Lemon Law kicks in.

I haven't come acrosss a similar prob on the forums and the service advisor hadn't heard of it before either. What are the symptoms of the N54/N55 HPFP failure?
 
#8 · (Edited)
I haven't come acrosss a similar prob on the forums and the service advisor hadn't heard of it before either. What are the symptoms of the N54/N55 HPFP failure?
Exactly what you are experiencing are bad HPFP symptoms, plus sometimes dying at a stoplight idling as well. But many other things can cause the same symptoms, even something minor like a bad sensor or a loose connector.
 
#6 ·
What do the rpm's do when this happens? Pause, reduction? Any particular RPM?

If the car is going into limp mode I haven't seen anything like that posted yet.

The N20 and ZF 8HP trans do however have a known slight hesitation during hard accelerations but this is only a pause and this does not sound like what you are experiencing.

If the car is going into limp mode, be concerned that things are not right. If it's still going on after they said it's fixed drive it back in to the dealer.
 
#9 ·
There's definitely something wrong with mine. At first I thought it might be normal as the hessitation was rare. When it hessitates it feels like it misses a beat and has a jerky feel for a tenth of a second. It got so bad that everytime I put down the throttle at least half way while doing 3K RPM or more it would buck continuously with each buck being a very brief 10th of a second. If I let it buck more than 4-5 times, the computer would shut the car down into limp mode where the car is forced into 6th gear max while in D so the RPMs were about 3K or more on the freeway. There's a large half engine symbol lit and the Service Engine Light flashes. At that point the car felt like it was running on 3 cylinders, not wanting to go over 75 MPH and shaking noticeably especially at lower RPM. I could force it into 8th gear in Manual mode, but it would shake violently. At that point you're pretty much forced to pull over. It even had a very lump idle, like 3 cylinders. After restarting, it would run normal until I pushed it again. As soon as it would studder, I'd back off to avoid going into Limp mode. Clearly there's something wrong with my car.

Perhaps others may have a minor case and think it's normal, but it's not. It may be a matter of time before it gets worse. The two N20 F30's I've driven don't exhibit this at all and that should say it all since they all have the same engine and transmission.
 
#11 ·
What you are describing is not normal at all.

I have no hesitation at all in the 35i X1, I dont drive it every day but one time it felt like the engine shut down completely for half a second when accelerating slowly and first thing I thought was HPFP. My wife has put 1200 miles on it and says she never noticed anything, she is pretty observant about how her cars run.

If its something that happens often and you got a CEL I'm sure the dealer will be able to figure it out. All it takes is one bad 10 cent part to shut a whole car down..
 
#13 ·
Well, it seems like the dealer couldn't figure out the problem yet. They swapped coils and injectors to see if the miss occurs on the same of diff cylinder, but after that they couldn't get to fail again, so now I have to pick it up again... I doubt it's been fixed...

It's a dramatic hessitation for a split second, so it's obvious even to passengers. Only happens on hard acceleration above 3K RPM.

I don't think this is an X1 thing, I think it's the N20 or the 8-spd tranny.

I'll keep you posted on what I find out tomorrow.
 
#15 ·
They didn't do anything to "fix" it. As part of their diagnostic process, they swapped components to different cylinders since the miss was at Cyliner 4. After they did that, they couldn't get it to repeat.

As I drove it 5 miles home the symptoms seemed to have disappeared, but I didn't drive it very hard since the engine was still cold. It's definitely better than it was and maybe the problem was related to incorrect assembly, like a loose or misaligned component. It's my wife's primary car and she has never experienced the issue since she drives conservatively, so I'll have to log some miles on it this weekend to know if the symtoms have disappeared.

I'll report back.

I'm curious to know if anyone has experienced any symptoms like mine had... Please reply if you think you may have a similar issue. Thanks.
 
#16 ·
They didn't do anything to "fix" it. As part of their diagnostic process, they swapped components to different cylinders since the miss was at Cyliner 4. After they did that, they couldn't get it to repeat.

As I drove it 5 miles home the symptoms seemed to have disappeared, but I didn't drive it very hard since the engine was still cold. It's definitely better than it was and maybe the problem was related to incorrect assembly, like a loose or misaligned component. It's my wife's primary car and she has never experienced the issue since she drives conservatively, so I'll have to log some miles on it this weekend to know if the symtoms have disappeared.

I'll report back.

I'm curious to know if anyone has experienced any symptoms like mine had... Please reply if you think you may have a similar issue. Thanks.
'04 BMW 330i had power loss and hesitation while driving uphill exiting a tunnel. It was a bit un-nerving as the hesitation lasted for perhaps 10 seconds. But then it smoothed right out and all was well.
It set a CEL though and the dealer stated the CEL code was "multiple misfires". They never could reproduce and it never happened again.
I figured a bit of condensate found its way into the fuel stream and once it was gone so was the problem.
 
#17 ·
Problem seems to be finally fixed after the third attempt. It was a defective ignition coil. They couldn't tell this from the codes and they could not reproduce the error, so they swapped parts in an effort to diagnose. It was through deduction that they determined a coil should be replaced, though they were still not certain. It was up to me to tell them if it was fixed.

It actually got worse before I brought it back the last time, so I'm glad we were able to figure it out.
 
#18 ·
i have read on other X1 forums that the N20 has had several injector issues and was a major reason i switched my car to a 35i. the problems you have spoke about seem similar to the ones that people with bad injectors had.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top