+- CarTechnoloGY (https://cartechnology.co.uk)
+-- Forum: Discussions All about Software and Hardware (https://cartechnology.co.uk/forumdisplay.php?fid=310)
+--- Forum: Automotive Help & Discussions / Software and Hardware (https://cartechnology.co.uk/forumdisplay.php?fid=40)
+---- Forum: BMW - Mini - Rolls Royce (https://cartechnology.co.uk/forumdisplay.php?fid=61)
+---- Thread: Solved ✔ Engine hard to start when is hot (/showthread.php?tid=60508)
Engine hard to start when is hot - masa52 - 11-02-2022
Hi
The problem is that when the car is hot wont start as it should
Has to crank about 2-3 seconds
When is cold start perfect
Car is BMW 840d with b57 engine
15K mileage
I’m run out of ideas what can cause that problem!!!
All tests are perfect
All adaptations and corrections reset
Software updated
Rail with sensor and valve changed
Coolant sensor changed
Camshaft sensor changed
Intake sensors checked
Throttle changed
Air mass checked
Fuel filter changed
Fuel temp and pressure sensor checked
Injectors perfect
Fuel pressure perfect
No idea maybe someone has had similar issue
RE: Engine hard to start when is hot - inspi1981 - 11-02-2022
Crankshaft sensor was changed with what?
Used, new, oem?
RE: Engine hard to start when is hot - masa52 - 11-02-2022
I did not change crankshaft as its shit access to it
I changed camshaft sensor sorry my mistake
RE: Engine hard to start when is hot - Node - 11-02-2022
So much part waste and you haven't changed the main sensor responsible for fluent start? Have you at least checked in live data you get correct starter rpms immediately after starting crank?
RE: Engine hard to start when is hot - inspi1981 - 11-02-2022
Then change crankshaft sensor, use only OEM, brand new
RE: Engine hard to start when is hot - masa52 - 11-02-2022
As said all live data are perfect
Rpm fine after start
Car drives perfectly apart hot starting
Im pretty sure its some silly problem but its hard to find as all data is correct
I know it’s stupid idea to replace parts but its no any other way to find the issue
RE: Engine hard to start when is hot - Node - 11-02-2022
You should look at rpm live data WITHIN those 2-3 secs when car is not starting as you would expect. Of course there are no problems after if car runs.
RE: Engine hard to start when is hot - jaki - 11-02-2022
And fuel pressure is ok, when STARTING? not when engine runs.
RE: Engine hard to start when is hot - masa52 - 11-02-2022
Fuel pressure looks fine but what I noticed its when is hot pump too reach nominal value need more time. I will upload bit later video. Maybe this is the case.
Attached videos
If you have any other suggestion what to test I can do this
thanks for help
RE: Engine hard to start when is hot - okolo - 11-02-2022
(11-02-2022, 13:19 PM)masa52 Wrote: Fuel pressure looks fine ............ Maybe this is the case.
Pressure is not good ... is low and slowly grows !!!
There may be a lot of reasons:
- fuel tank
- fuel filter
- flow-control valve
- injectors
Start from flow-control valve (2).