oskarklein24

Mercedes ML Diesel Cylinder Pressure Issue Resolved

Evening. My 2005 Mercedes ML diesel has developed a rather annoying issue. I'm getting cylinder pressure fluctuations, which seem to be causing higher fuel consumption and a noticeable reduction in engine power. The check engine light is now illuminated. I've checked the basics – air filter, MAF sensor – but haven't found anything obvious. Could a faulty fuel injector cause this, or is it more likely something related to the turbocharger or even piston rings? The car's only done 62249 km, so I wouldn't expect major wear just yet. Could it be something simple like a timing belt issue, or am I facing a crankshaft issue?

A 2005 Mercedes ML diesel was experiencing cylinder pressure fluctuations, leading to higher fuel consumption and reduced engine power, with the check engine light illuminated. Initial checks of the air filter and MAF sensor revealed no issues. Potential causes considered included a faulty fuel injector, turbocharger problems, piston rings, timing belt, or crankshaft issues. Ultimately, a professional diagnostic revealed a faulty sensor disrupting the fuel mixture, which was resolved under warranty.

Did this summary help you solve your problem?

4 comment(s)

Cylinder pressure fluctuations can indeed stem from fuel injector issues. Have you considered assessing the injector spray pattern? A leak-down test might also offer insights. Though less frequent at your vehicle's mileage, worn piston rings can contribute. The crankshaft position sensor should also be checked. Is the engine misfiring?

Thanks for the quick reply. I haven't checked the injector spray pattern directly, no. Is that something easily done at home, or does it require specialized equipment? Also, if the crankshaft position sensor was faulty, wouldn't I expect more consistent misfires, rather than just these fluctuations?

Injector spray pattern assessment generally requires specialized equipment for accurate diagnosis. Regarding the crankshaft position sensor: you are correct; consistent misfires are more typical. However, intermittent signal disruptions can also occur. Given the potential complexity and consequential error you’re experiencing, a professional diagnostic assessment is advisable. It might save you time and money in the long run.

Appreciate the advice. I took it to a workshop, and it turned out to be a faulty sensor causing all the issues. It was throwing off the fuel mixture and causing the cylinder pressure variations. The repair cost was 0€, covered by an extended warranty!

rmh_community_comment_box_header

community_crosslink_scanner_headline

community_crosslink_scanner_intro

community_crosslink_scanner_title

community_crosslink_scanner_price

community_crosslink_rmh_headline

community_crosslink_rmh_intro

community_crosslink_rmh_title

community_crosslink_rmh_subtitle

community_crosslink_rmh_brand

MERCEDES

community_crosslink_rmh_model