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Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53150
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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OK, replaced the WUR, checked out at 45 lbs. pressure. The

Customer Question

OK, replaced the WUR, checked out at 45 lbs. pressure. The car ran much better but would not kick down to idle speed. That's another issue to un-lock. It sat for 2 weeks. Started it up and it ran like crap. Sluggish, couldn't hold an idle speed. engine shaking, plus, the longer it ran, smoke came rolling from the rear of the engine compartment, then I shut her down. The floor on the passenger side got hotter than hell also. Any ideas?
Submitted: 6 months ago.
Category: Mercedes
Expert:  Marty replied 6 months ago.
It sounds like it's dumping fuel. Recheck your pressures first. If you have good fuel pressure I'd suspect a faulty fuel distributor.
Customer: replied 6 months ago.
Fuel distributor has been replaced before WUR.....that was $3,000. Has to be something else.
Expert:  Marty replied 6 months ago.
you installed a brand new one? Have you tried adjusting the fuel mixture?
Customer: replied 6 months ago.
No. How is that done?
Expert:  Marty replied 6 months ago.
Click here for a good article on the procedure. Counterclockwise with the screw will lean the mixture. You can disregard the electrical part of the article. Mainly concern yourself with the first paragraph regarding the mixture adjustment. A simple test of the mixture is to pull up or press down slightly on the air flow sensor plate. If the engine runs better when you pull up on the plate your mixture is too rich. If it runs better when you press down on the plate your mixture is too lean.
Customer: replied 6 months ago.
OK. I re-connected the fuel pressure lines and gauge between the fuel distributor and the WUR. Car started right up. 50 lbs was the reading. Got the mixture good on the fuel distributor for a nice idle. Now, the problem lies when I go back to the hard line from the FD to the WUR. Things just go to hell there. It runs sluggish, wants to die out, etc. Could there possibly be a blockage in that line?