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320d N47 Violent Idle Rattle, are my injectors bad?

904 views 0 replies 1 participant last post by  itstheodor 
#1 · (Edited)
I had just arrived from a 40km drive. Car performed normally, high speed was fine, absolutely no (new) vibrations or symptoms, until I arrived in my town and stopped at the railway crossing. When it reached about 5 km/h and engine had gone down to idle speed, car started rattling and vibrating hard.
After I accelerated from the crossing, the car changed completely. Screeching noises coming from under the hood at different RPMs, vibrating randomly during driving. Started and restarted the car many times and the rattling will not go away. Engine start is also very rough.
The rattling is the same regardless of gearbox position (P, N, D, R, S).

I plugged in ISTA+,
There are no faults stored. No misfires. Nothing. Matter a fact, I have never had any misfires or any other faults regarding the engine.

I ran the "Smooth Running Control" ISTA+ service function:
Starting values, at idle, ~750 RPM:
Cylinder 1: 0 mg/Hub
Cylinder 2: -0.9 mg/Hub
Cylinder 3: 2.7 mg/Hub
Cylinder 4: -1.7 mg/Hub

Values when I raised engine speed to ~1300 RPM
Cylinder 1: -0.6 mg minimum | 0.1 mg maximum
Cylinder 2: -2.7 mg minimum | 0.0 mg maximum
Cylinder 3: 0.0 mg minimum | 7.2 mg maximum
Cylinder 4: -4.5 mg minimum | 0.0 mg maximum

Injector 3 especially was going up and not stopping, even reaching 8.0 mg/Hub correction. ISTA+ verdict: Injector 3 needs replacement. Looking at the values, I am guessing it is both injector 3 and injector 4?

Are the injectors bad?

Please help if you can,
Thank you in advance and for your attention!
 
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