rough idle-1989 560 SEC
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Joined: Jan 2009
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1989 560 SEC
rough idle-1989 560 SEC
Bought a SEC around labor day so I haven't had it for long-I'm having idle problems -it runs somewhat rough- almost feels like a lump-especially when it's cold-does better when it warms up-also a little smoother when it's in gear.have been playing with the air/fuel mixture a little-when I richen it it seems to smooth out but then the idle fluctuates between 900 -1500 so I had the idle control unit tested and it was fine-I've leaned it out to a point where the idle does't fluctuate -seems to perform much better where I have it but like I said-a little rough recent work-plugs ,wires,cap,rotor,timing chain,all new filters -has 112,000 miles-am I possibly looking at a vacuum problem or perhaps something electronic?
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Joined: Jun 2006
Posts: 87
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From: USA
ML500 AMG pkg
Check for vacum leaks and if none found then start with the basics!
1. compression and leak down test
2. camshaft timming
3. hydraulic element setting (valve lash, they can be set)
4. check for worn camshaft lobes
After these check O2 sensor for proper operation, internal fuel leak test, fuel pressure. Also a leaking injector as was mentioned by another member. Bad plug wires, wrong spark plugs, inproper gaping of electrode......
1. compression and leak down test
2. camshaft timming
3. hydraulic element setting (valve lash, they can be set)
4. check for worn camshaft lobes
After these check O2 sensor for proper operation, internal fuel leak test, fuel pressure. Also a leaking injector as was mentioned by another member. Bad plug wires, wrong spark plugs, inproper gaping of electrode......
