Unfortunately we do not accept new members for free, Now Registration cost 30€, if you are interesting Send Email to [email protected]

X1 E84 N46N hard start or long crank after short rest
01-08-2023, 19:25 PM,
Post: #1
X1 E84 N46N hard start or long crank after short rest
Am at my wits end trying to resolve a hard start issue N46 engine. The engine starts ok when hot or cold but has difficulty firing when rested from hot for 5+ minutes.

1. Cam/crank sensor - no luck
2. Tried with eccentric shaft disconnected to disable valvetronic
3. Tried throttle valve
4. Checked temp sensor when hot all plausibl
5. Fuel pump - strainer clean, seems to deliver fine

What else could I look at or retest? Only thing I can think of is dme but I doubt thus. I would appreciate some suggestions.
Quote this message in a reply
01-08-2023, 19:58 PM,
Post: #2
RE: X1 E84 N46N hard start or long crank after short rest
Is there spark and injector pulse? If yes, any chance for a fuel vapour lock? I don’t know the engine very well.
Quote this message in a reply
01-08-2023, 19:59 PM,
Post: #3
RE: X1 E84 N46N hard start or long crank after short rest
Hi ,some ideas
1) Check fuel pump relay ,i dont remember if this car has ekps.
2)Check or replace spark plugs
3)Remove one of two camshaft sensors before shutoff the car so the valvetronic open the valves full and then you can shutoff the car leave it around the time(5+min) as you say and then check if the car start normal


Quote this message in a reply
02-08-2023, 03:06 AM, (This post was last modified: 02-08-2023, 03:09 AM by willisodhiambo.)
Post: #4
RE: X1 E84 N46N hard start or long crank after short rest
(01-08-2023, 19:58 PM)liviu2004 Wrote:  Is there spark and injector pulse? If yes, any chance for a fuel vapour lock? I don’t know the engine very well.


There is because it seems to fire but not prope4ly. Vapour lock seems plausible but I can't see where it would develop. Worth investigating

(01-08-2023, 19:59 PM)fireblade9 Wrote:  Hi ,some ideas
1) Check fuel pump relay ,i dont remember if this car has ekps.
2)Check or replace spark plugs
3)Remove one of two camshaft sensors before shutoff the car so the valvetronic open the valves full and then you can shutoff the car leave it around the time(5+min) as you say and then check if the car start normal

These I tried. This car has no fuel relay, except the one inbuilt into the junction box. Ill try another i see. .

Plugs were already replaced and vvt already tested by removing eccentric shaft sensor as that also sets vvt to max open.
Quote this message in a reply
23-08-2023, 05:12 AM,
Post: #5
RE: X1 E84 N46N hard start or long crank after short rest
Problem still not solved. SO far tested with replacement pump, injectors and rail, battery. Same issue. 10-15min rest always results in a long crank hard start. I have no plausible explanation for this behavior. Strange some of these problems
Quote this message in a reply
23-08-2023, 07:04 AM,
Post: #6
RE: X1 E84 N46N hard start or long crank after short rest
Have you checked compression when it long cranks/hard starts when hot? Have seen one or two with piston rings sticking, although I seem to remember these were N42.
Quote this message in a reply
23-08-2023, 07:10 AM,
Post: #7
RE: X1 E84 N46N hard start or long crank after short rest
Why don't you graph as many parameters (for example using ISTA expert mode) as you can during normal startup and during this issue then??? We would at least have something to investigate. Now should we be listing all possible reasons for engine not starting here???

On diesel I would say 90% clogged injectors. Never seen this on petrol a engine, but it could be possible that someone was putting crappy gas into it to clog them. But then it is CLEARLY visible in certain parameters on the graphs!!!

You could also at least stop cranking this "long" crank before engine starts and check whether spark plugs are wet, etc. Now NOTHING we can think about AT ALL!!!
Quote this message in a reply
25-08-2023, 07:24 AM, (This post was last modified: 25-08-2023, 07:28 AM by willisodhiambo.)
Post: #8
RE: X1 E84 N46N hard start or long crank after short rest
(23-08-2023, 07:04 AM)tonemoz Wrote:  Have you checked compression when it long cranks/hard starts when hot? Have seen one or two with piston rings sticking, although I seem to remember these were N42.

Not checked compression yet but opened the cylinder head and checked integrity of the gasket. Was OK. The issue is only present when car rests for 10-15min. Cold start OK, restart any time before about 10min OK, restart after say 1hr - OK. However, let me do a compression test I see.

(23-08-2023, 07:10 AM)Node Wrote:  Why don't you graph as many parameters (for example using ISTA expert mode) as you can during normal startup and during this issue then??? We would at least have something to investigate. Now should we be listing all possible reasons for engine not starting here???

On diesel I would say 90% clogged injectors. Never seen this on petrol a engine, but it could be possible that someone was putting crappy gas into it to clog them. But then it is CLEARLY visible in certain parameters on the graphs!!!

You could also at least stop cranking this "long" crank before engine starts and check whether spark plugs are wet, etc. Now NOTHING we can think about AT ALL!!!

While cranking the engine tries to fire but does not succeed and reties a few times. Occasionally it stops and stalls then fires the second time like nothing happened. Fuel refreshed and the problem has existed for the last one year!!

The symptoms point to insufficient fuel delivery. And now that I think about it let me confirm that the injectors are on the correct plug and not mixed up!!
Quote this message in a reply


Possibly Related Threads…
Thread Author Replies Views Last Post
XZBMW Resetting a short circuit fault in a FRM module TIGHTFIN 10 1,146 24-02-2024, 22:29 PM
Last Post: vierchatura
  E91 2011 need Start/Stop OFF + NCS Dummy error roanoke 3 138 20-02-2024, 08:53 AM
Last Post: test01
XZBMW Deactivate Startup assistant / Hill start assistant? F11 Blondy 0 108 16-02-2024, 08:58 AM
Last Post: Blondy
  G02 dkombi2 problem boot start cupra80 2 244 22-01-2024, 07:00 AM
Last Post: cupra80
  Bmw 328i f30 1B2002 Ews protection against tampering: no start value programmed Bavrian 2 230 10-01-2024, 10:30 AM
Last Post: Bavrian
XZBMW Solved ✔ E92 M57N2 dsc,abs,gearbox, not start, problem ArcziArcz 6 383 09-12-2023, 07:14 AM
Last Post: ArcziArcz
  How long does the ISTA+ 4.44.3x update take to 4.45.1x with Offline license? 2013m5 15 1,216 02-12-2023, 01:04 AM
Last Post: NeRkO20
XZBMW CAS2 + MSV70 will not start after battery disconnect / lost DME<->CAS sync bmw335coding 1 217 11-11-2023, 12:19 PM
Last Post: johann74270
XZBMW BMW E90 lci MSA start stop boweld11 4 306 07-11-2023, 10:43 AM
Last Post: Brandy
XZBMW BMW F12 650i crank but won't start PelsonBMW 6 501 29-09-2023, 17:32 PM
Last Post: PelsonBMW

Forum Jump:


Users browsing this thread:
1 Guest(s)

Return to TopReturn to Content