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Old 10-16-2002, 12:26 PM
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mbe32094 mbe32094 is offline
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Join Date: Feb 2002
Location: Bay area, CA
Posts: 107
Rough idling and loss of power

I got everything back together now.
After few miles of driving, I don't see any oil leaking from the engine anymore. But, there are problems. The car is idling very roughly and the engine is shaking. Also, I noticed that it has lost power. The idle RPM is normal below 1000.
This is what I did after I encountered these problems.
1. I replaced the spark plugs with Bosch super plug from MB dealer.
2. Replaced one of the vacuum hose under the intake manifold because I thaught it was leaking vacuum.
3. Checked the voltages on the fuel injector plug while the engine is running ( 12+ volts).
4. Measured the resistance on the injectors pins (15 ohms).
5.Measured the spark plug wires (1.7 to 1.9k ohms).
6. Watched the valve while the engine is being cranked, to make sure it is operating properly. They're ok.
7. I checked the diagnostic code and I got a reading of number 7 and 10. Number seven according to the manual is ignition system failure. Number 10 is mass flow air sensor. Maybe it senses when I disconected the intake pipe (top of the engine) while cheking for spark plaug voltage.
8. I tried to remove one spark pug wire one at a time to see if there is a change is the idle.
a. Number one plug wire removed ( no change in idle),
b. Number 2, 4, and 5 (also no change in idle).
c. Number 3 removed the engine dies.
d. number 6 removed the engine dies also.
9. I repalced the seals on the fuel injector. I also cleaned the injector tip by sprating it with an intake valve air cleaner sparyer.
10. I checked the coil to if there is a presence of high voltage. While removing the spark plug wire I saw high voltage spark coming out.
11. I checked the compression on the piston cylinder and I got a reading of 150 to 170 PSI on all pistons.
12. I checked the top dead center of all the pistons and here what I found.
OTDC - 1 and 6
120 - 2 and 5
240 - 3 and 4
The cd manual says at 120 is 2 and 4 and 240 is 3 and 5
When I removed the timing chain I followed the manual and marked the cam gears and the timing chain. Put the engine at OTDC. They were put back together on their proper markings.
What seems to be the problem causing the rough idle and loss of power?
Any advice is very much appreciated.
94 E320 Silver 210000 miles
94 740il Pewter Green 97000 miles- Retired
05 S430 4Matic
07 Lexus IS250
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