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I just wrote my question and it prompted me for further explanation. Let me know if you have my original question 6 or 7 sentences long
Hi Aaron,sorry, but no - your information has not come out.Could you give me some brief information again please.Looking at your previous posts it is a C220 petrol.Obviously cutting out - when hot/cold?When driving or more at idle/coming to a stop?Any problems starting?Best regards Paul
I have a 1996 Mercedes C 220 with 230,000. Lately I have been having trouble with it idling so I purchased a throttle body, plugs, and wires which has made a big difference. However, one problem sill exists. when i start my car and it throttles up all is fine, on the other hand, as it idles back down the a/c pump kicks in and causes enough drag to stall the engine. Now this doesn't happen every time I noticed it. Especially though I have noticed it when the engine is warm. Could this involve the vacuum system? No check engine lights are on at present. Although, we just cleared the codes and it did have before one p1750. Please help if you can!
Hi Aaron,there are a number of things that could be causing the problem.I would certainly start by checking for air leaks around the manifold - there are 2 breather hoses under the manifold that pushes onto connectors in the cylinder head & a larger hose on the Y peice that connects them - check these & the plastic Y piece they join into - they are prone to perishing & splitting.Also check the injector seals to ensure they are not leaking.Spraying around the seals with intake cleaner is a good way of checking - the engine will rise in revs if it draws the cleaner in through a leaking seal or hose.Also check the MAF (air mass) sensor to ensure that it is functioning correctly - you would need to check the reading on a diagnostic tool, or possibly swap with a known good one if available.The crankshaft sensor can also cause stalling problems - although this is usually followed by not being able to start the car again afterwards.Let me know if you need anything else.Best regards, Paul
What are some good ways to check for leaks around the mainifold with those connectors?
Hi Aaron,As said, intake cleaner is a good way to test if it is drawing in air.Also visually check the pipes, although they are quite difficult to get to with the manifold still on! a small inspection mirror with a telescopic handle is very handy for this kind of thing.I have attached a picture of the hoses (item #16 - 2 of these that go from the Y piece #119 & the larger hose #110) from the parts computer.Best regards, Paul
Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes
Are the steps you gave me to do. Do they tend to be the most probable causes of this issue.If you have any other would appreciate them as well!
Hi Aaron,There are many things & have given you the most probable from what you have described.other things/tests could include:engine compression testcheck plugs for condition & oil fouling from valve stem sealsfuel pressure & flow test including holding pressure to check pump/regulator & fuel injectors.fuel vapour tank purge valve.O2 sensor.engine ECUwas the throttle body brand new & initialised on a diagnostic tool when installed?Let me know if you need anything else.Best regards, Paul
I would also like to mention that once the a/c is turned on and the engine is running I have no problems idling or on the road. Thanks again
Hi Aaron,I think from what your describing it is just the initial load from the compressor that is causing the engine to stall when it cuts in.I dont think it is actually the compressor causing the fault, as long as the compressor is working fine with no noises.Best regards, Paul
Throttle body new,yes iniatised on a machine no. Thanks for all the info
No problem Aaron,I would have thought if it was an issue the car would not idle at all, but may be worth setting up on a diagnostic tool such as Mercedes STAR to initialise - this programs the throttle stop positions in the ECU.Best regards, Paul
Thanks for the help.
Your more than welcome Aaron,Let me know how you get on.Best regards, Paul
One final question. Sorry because of misunderstanding. would you still reccomend going thru the troubleshooting steps any way
Hi Aaron,I would check for air leaks on the intake & hoses as it does not take much to do that, if that proves no good the next step I would take is to get the car on a diagnostic tool that can re-adapt the throttle body & check sensor values & for any further codes.Best regards, Paul