Now runs rough with no power

BENZINE

MEMBER
1984 MERCEDES BENZ 190E
14,000 MILES

Professional cylinder head rebuild.190e... Leaving fluffy black deposits on all plugs and in exhaust. Since reassembly, I have double checked compression. Cold compression test 1/130, 2/130, 3/140 (new exhaust valve here), 4/125. I have also double checked crank to cam timing... Both top dead center marks correspond to distributor position and compression stroke and firing order. I have also replaced the fuel pressure regulator. But she is still running rich and rough. What could the matter be?

2 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Check the fuel pressure if its within specs-start here

1. Excessive fuel pressure can be cause by restricted fuel return line

2. Defective Oxygen Sensors.

3. Leaking injectors and fuel pressure regulator.

4. Coolant temperature sensor out of calibration.

5. Restricted air intake system.

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Saturday, February 4th, 2012 AT 5:41 PM

BENZINE

MEMBER
2 POSTS

Thank you, Rasmataz, for your list of helpful suggestions. #4 led me to check my sensor hookups and I found I had inadvertently switched two similar connections for the fuel sensor and the coolant temperature sensor. I completely overlooked this until your comment made something click and I checked my before photos again (more closely.) My 190e is now running smoothly, with thanks to you. The moral of the story is to always take photos and tag everything... Check and double check... Then triple check. Three times was the charm. Thanks again for pointing me in the right direction. Your guidance was most appreciated; my confidence restored!

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Monday, February 6th, 2012 AT 5:48 AM