A Curley One?

[lord1nz]

My XM V6 S1 starts well but wont rev over 2000 rpm. It back fires through A/filter and when driving just wont go past 2000rpm. Persist with this for a while - start and stop engine several times and it all comes right and off down the road you fly into heaven - cause thats what its like to dive in my XM - once it gets over its hissey fit (must be a woman) - Any bright ideas from my friends on XM Forum??? Regards Graeme

[lez]

mine wont even start some mornings, runs badly, backfires down exhaust, wont rev, stops/starts as i pull away, then once its gone 1/4 mile and got warm its fine.

reason, cheap fuel from the supermarket, that lovely cheaper bioethanol stuff...

you not using it are you?

[lord1nz]

No - fuel is fine - 96 octane - no mixtures

[lord1nz]

Someone has suggested that its in "Limp home mode" beats me - Here's what i did at weekend - Got in -started engine and drove off - when the engine faltered I turned key off and on - away we went for a couple of minutes and same again - engine faltered and wouldn't rev over 2000rpm - turn key off and on again - off we went - repeat process about 10 times and then no problem - off like a robbers dog. Who knows?? French madness at its best!

[Dieselman]

The mixture is too lean when cold so it's spitting back. Either the engine temp sensor is faulty or if it has one the MAF.

[lord1nz]

Have replaced Air Temp Sensor = no change - MAP sensor chrcks out as OK -- Still have problem.

[UFO]

checked the ignition module lately?

[DerekW]

Well said Craig, my money's on that little beauty.

And unlike some XM bits it's easy to get, easy to replace and not too expensive.

[Jan-hendrik]

Hmmm. Interesting. A topic started more than a year ago is brought to life again

My XM developed an engine stalling problem when cold in recent months. Fortunately we do have a dealer here whose services are excellent and the Lexia indicated a faulty engine coolant temperature sensor.
Like I said, the engine would stall when cold - but not always - it would rev properly when you put your foot down, and the problem was gone as soon as the engine warmed up.
I had the sensor replaced and all is fine now

[lez]

where is that sensor exactly... whats it look like to distinguish it from others?

[Zaphod]

Air temp sensor is not the engine temp sensor, It does sounds like it thinks it's warm, and thus not using the cold start enrichment, this would lead to the engine running lean if at all till it has warmed up, and lead to the blowbacks you have experienaced, not sure about the 2000 limit. Once wramed up it would run perfectly, and start fine while warm.

Chenage the engine cooolant temerature sensor, By the way there may be two of these, one is for the dash guage, the other is for the engine managemnt, its the second one you should change