BenzWorld Junior Member
Date registered: May 2009
Vehicle: 1973 450SL -- 1988 560SL
Location: Warren Maine -- USA
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--- update - I checked the throttle switch with an ohm meter and it is supposed to sway from infinity to zero ten times as you slowly open it - the one on car did 7 swipes and then nothing until you got to near end of swing and you would get one more - I replaced the unit with a used on, tested it first and it did ten nice uniform swipes, car would start and run like crappola for a few mins then die with the sender hooked up so I made a little progress. I feathered gas to get unit to operating tempature and car would idle at like 150 rpm long enough for me to check fuel rails, and intake area with carb cleaner with an extension wand I rigged up - on passenger side "under" intake rpm's would raise and car would "iron" out at idle. I took intake assembly off of car and it appeared that the two rear rubber seals that go between the two intake halves were leaking, so I replaced them and all of the injector seals. Car started right up and will now idle VERY LOW RPM and anytime you try to throttle it up it will backfire and pop through the intake bore. I presummed this was a lean misfire, so I again checked intake, etc... with the carb cleaner - no leaks found. I then starting checking, as I had before SEVERAL times the basics like AAV, cooling sensors, I had already replaced the coolant temp and 100 C units and all looked good. UNTIL i started crimping off fuel lines with a pincher, when I shut down the return line the car idled up and I could snap throttle and car seemed to run perfctly. I know the car has 35 psi coming from pump and am going this morning get pressure reading coming off of pressure regulator - I think thats the problem now - any thoughts on this?? Thanks.
Last edited by nemw01; 09-20-2011 at 06:01 AM.