Torgeir
Member Since: 14 Apr 2021
Location: Trondheim
Posts: 29
  
|
| Diagnose faulty injector only present at certain rpm?? |
|
Is there a way to diagnose which injector is faulty when it occurs only at a certain rpm and throttle?
All injectors has been out of the car and tested, new tips on all 6 and 2 were fixed some more since it had a higher return leak. All done by local injector specialist company.
Since then there has been the typical knocking sound when it is warm caused by one of the injectors but only at 1400-1800 RPM and very low amount of throttle. If the throttle is increased it disappears. We spoke to the injector company and they only test the injectors at "idle" and at full throttle and a few places in-between so it could be that they miss it if it is a periodic fault in the actuating element, especially if it only happens when warm.
It is fine on idle and a leak-off test shows all injectors are good (leak-off is done at idle). Injector balancing show Injector 1 and 6 has values around 1000 and the rest lower at idle. When I logged the injector balancing Injector 1 went above 1200 for a short while when I was driving slowly trying to listen for the knock. So my main suspect is injector 1, but is there a way to diagnose which one it is for sure while they are in the car?
In addition the car goes into limp mode on hard acceleration, LPFP and HPFP has been changed. Theory is that at least one of the injectors has a bad valve on the return still. Question is which one?
|
 2nd Aug 2021 9:22 pm |
|
|
jenseneverest
Member Since: 12 Jun 2017
Location: somewhere
Posts: 763
 
|
it is my understanding that the injector solenoid fails, as well as the general wear and tear seen on the "tips" like in all injectors. That is a lot of parts changed..... what codes are you now getting ?
If it were me i would move the suspected problem injector somewhere else to see if the problem goes with it, or if your pretty sure it is number 1, change just that one.
It may be an idea to check the injector looms as well.
|
| 2nd Aug 2021 10:06 pm |
|
|
Torgeir
Member Since: 14 Apr 2021
Location: Trondheim
Posts: 29
|
To hear if the problem moves with the injector you would have to lie on top of the engine bay and drive with the hood open.  The noise only appears when driving slowly. When reving the engine at standstill in neutral or holding it on the brake it does not appear.
|
| 2nd Aug 2021 10:28 pm |
|
|
Torgeir
Member Since: 14 Apr 2021
Location: Trondheim
Posts: 29
|
Update: Ended up replacing all injectors with new ones as I got the money back from the bad job refurbishing them.
|
| 5th Sep 2021 1:43 pm |
|
|
