Hello. I am the owner of a focus mk2 1.8 tdci 115 hp from 2006. I have been struggling with engine jerking at idle for a long time. The engine runs erratically and jerks the whole hut. Suspicion fell on the injectors. As recommended, I went to the plant, the injections were checked on the table, the result was very good, the injections were operational. Every now and then the indicator light of the red gear with an exclamation mark in the middle illuminated. After connecting to the computer, errors popped up: P0090 - discontinuous P0001 - Fixed
Both were related to the fuel pressure regulator. Recommendation. Replace the solenoid valve on the pump. Solenoid valve replaced. The mistake did not repeat (for 2 months) but still jerks the doghouse. After some time, when starting from number one, I felt a momentary interruption (it was losing power), for a second the sound of a rattling noise from under the hood and then an error related to the fuel pressure regulator. Suspected pump: / We checked the pressure and here comes shock. It even jumped up to 450 bars..woow. WTF? I bought a used, working pump. Improvement after replacement only in terms of interruptions. The error stopped, but the pressure reaches 400 bar ... The fuel pressure sensor has been changed, but unfortunately it is not. Compression was checked and 26 bar everywhere (good). The clips from the return overflow pipes fell out 4 times. You know what it smells like ... flooded engine: /. Above 1k rpm, the engine works perfectly. Gentlemen, save me. Could these be return lines? There is apparently a ball that should open? Fuel filter replaced (clean) If there are any ideas, I am waiting for info. 4 mechanics couldn't handle it .. I count on the power of this forum.
Similar symptoms can also be caused by the EGR valve, this nasty nasty stuff can mess up so much and not show an error, and the ECU tries to correct the fuel dose to the situation and collapses with errors in the form of fuel pressure, check the EGR valve if it is clean and does not jam.