W221 CDI Limp Mode

gilbert121262

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If you look through my past posts you will see that I have had problems with limp mode before. Had EGR Valve changed in Mar this year then IPS motor. All has been well until last week. Car went into limp mode 3 times in one day. Took it to indie who found following faults, EGR Valve IPS Motor and a sensor that I cant remember. He did say that it could be clogged up again as I spend a lot of time in London and it had’nt had a blast for a few weeks. Booked it in for service as due in 1800 miles anyway. Decided to keep it in S mode instead of C. Following day put it into C got the hump with the sport suspension setting. Turned car off for 15 mins got back in it and straight into limp mode. Turned off an on again all well so left in S mode. Had it serviced yesterday including air filters as clogged again, they never last for 2 services and fuel filter. Car fine last night when I picked it up fast and responsive. This morning all well when started it. Stopped after 15 mins to put a letter in post box, did’nt turn it off but when I got back in it got the distinctive clonk when put into drive that means it in limp mode again. Had just put back into c mode prior to stopping. Turned off and on all well again. Stopped car after 10 mins and started all well still. The next start it was in limp mode but engine light on now!!!. Took it back to be plugged in and this time EGR Valve air mass to low. Cleared fault and he said it could be one of the MAF’s but as they about £300 not sure what route to go down. Car alright this afternoon right up until I put it into C mode, 20 secs later limp mode again. Is this a coincidence or is moving it from s to c mode causing the problem. Any thought welcome.
 

WG M-B

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Nothing springs to mind on this one. Maybe someone else should take a look for you. Possibly blocked exhaust???
The mafs are part of the air trunking
 

Steve@Avantgarde

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The MAFs can be tested on STAR to see if they are measuring correctly. You say you used an Indie, but was it a proper indie with STAR diagnosis?

It could be you have the MAF fault code there as the engine ECU will use the MAF to put the engine into limp mode, common error made by some thinking its a MAF issue.

Have the air filters been replaced and the engine ECU been reprogrammed? That will throw up an engine light and limp mode if they have not been done/done properly! I have to be honest, I dont think I have replaced a MAF on this engine for poor running yet, they tend to be fine.
 
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gilbert121262

gilbert121262

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Thanks for your replies. The air filters have been replaced and he did reset ECU after they were done. He an ex merc man and seems to know his stuff but I dont think he has a star machine just a generic one. Anyone recomend someone in the surrey kent area that has proper star diagnostics. Look forward to a reply.
 
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gilbert121262

gilbert121262

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I'm in the surrey kent border so reading bit of a mission, thanks anyway.
 

st4

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Sounds like the manifold is gunked up and the swirl flap mechanism cannot operate as the manifolds are caked up with crap from the EGR. This would cause the flaps to default to closed reducing power drastically.

You need to get the linkages from the IPS to the swirl flaps checked and the manifold cleaned or replaced.
 
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gilbert121262

gilbert121262

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This is going to be shot down in flames as me clutching at straws, but bear with me. The first time my car went into limp mode after haveing Inlet port shutoff motor replaced, was in October. I remember it well because I was on blackfriars bridge 6pm thursday night in a torrential rainstorm. Then 2 weeks ago it started doing it again. I checked my credit card statements and every time it had gone into limp mode I had put esso diesel in. I only use esso or shell fuel due to garages on my route home. If I had put shell in no limp mode. Think I might open a can of worms with this statement but dates and limp mode occurences all match up. 60 litres of shell v power diesel put in today, will keep you informed.
Sure I will get some input on this one!!!!!
 
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gilbert121262

gilbert121262

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was talking bo**ocks again. Inlet port shut off motor gone again. Lasted 10k miles, excellent!!!!!
 


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