W202 250TD massive loss of power

[guydewdney]

Started losing power a while back, along with visible air in the fuel lines - so I naturally thought the air was the cause.

finally got round to fixing the air leak today, but it hasnt cured the problem.

symptoms: car starts perfectly and idles smoothly, albeit with a very slight diesel knock. No smoke. Rev the hell out of it (neutral or in gear, it doesnt make any difference) and it will 'redline' quite happily - for about 1 second, then the revs drop and its misfiring badly. allow to drop to idle, and it idles smoothly. immediately try revving again, and there will be bad misfiring. Alternativly, leave idling for 30 seconds, and it regains its breath.

My 'air' logic was that the lift pump was lifting enough to re-fill the fuel filter at tickover, and the fuel would be used up in the first burst, only for the air to come back again.

Blueish smoke when misfiring.

Running 90% veg oil 10% petrol (approx)

Do I need to go on ebay motors?

code reader in the post to me.

 

[Tinkerer]

Veg oil blocking the fuel filter hence pulling air into the fuel lines??

 

[guydewdney]

no air visible (now) in the lines - but can only really check at idle. will check again tomorrow. new filter, and the veg is cleaner than the diesel (500 quid centrifugal filter gets it really really clean). contrary to popular misconception, its the veg that pulls carp out of the lines that block filters, not the veg itself (usually).

 

[Dieselman]

it does sound like a fuel starvation issue, so either air being drawn in still or blocked filter or pipes.

Try revving t the engine sharply from idle and watch for air. You could also install a vacuum gauge into the fuel pipes and see if there is a blockage.

 

[guydewdney]

will do.