Troubleshooting cold engine hestitation/power loss? (not the MAF's/no error codes)
Well, this is the second time I change my MAF's, but this time the problems did not go 100% away.
On cold engine, the car is still hopping/wont run smooth by just driving steady at a fixed speed. This problem disapears when the rpm light goes out for 4' and 4.5' rpm.
Other thing is that I still are short of power. Can't get it to just spin by rolling at 1000-1500 rpm and floor it (yes, the DSC=off).
The ppl at the local dealer (man, they're knowledge sucks) says nothing is wrong according to their read outs from the engine (ever heard that before?).
So now, I'm giving up. The "specialists" on M-engines in Norway is 1800 km away, and that's to far away... And I cant just keep on changing parts as they're quite expensive in Norway.
Anybody with some really good ideas on what to look for?
Any measurements that can be done for compare that I could post here?
So it runs better once it is warm(er)? I would check the coolant temp sensor and wires (but that is a guess from similar symptoms on S14s).
Yes, when the 2 first leds at the rpm instrument goes off then she runs smoothly again. But still, the spinning is out of the question. I would loved to have her dyno'd to see what she performs now...
I would remove the spark plugs and check for excessive wear. AFAIK worn plugs would not always throw a code on the DIS, but would definitely affect performance adversely.
Also have a look at the condition of your air filters. You did not say when last she had a service, so worth checking.
Of course, more unlikely, but you could have been sold a factory defect set of MAF's. Check DavidS' post on how to test them, if you have not done so already.
I hope this might point you in the right direction.
Regards,
Rudi
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2001 Imola Red II E39 M5 - Stock
I would remove the spark plugs and check for excessive wear. AFAIK worn plugs would not always throw a code on the DIS, but would definitely affect performance adversely.
Also have a look at the condition of your air filters. You did not say when last she had a service, so worth checking.
Of course, more unlikely, but you could have been sold a factory defect set of MAF's. Check DavidS' post on how to test them, if you have not done so already.
I hope this might point you in the right direction.
Regards,
Rudi
I will check the spark plugs tomorrow then.
Air filters are ok, replaced them in May. Also did the Inspection II at the same time. The MAF's did I get from DavidS. But of course they could be defect, but I doubt that. The hesitation of the cold engine has "always" been there, it's just less noticeable just after I replace the MAF's.
The top three culprits would be MAFS, Spark Plugs, and O2 sensors (4). I would replace all three of those first and see if that solves your problem. If not then at that point you must dig deeper and spend more $$$. Unfortunately $tealers are the same world round! Clueless Keep us posted and good luck!
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2000 Silvr(354)/Blk(M1SW) 65k miles
Dinan Cans
Dinan Software
Might be a bad fuel injector. an engine requires more fuel to run smoothly when it is cold. Some cars have an extra fuel injector that works only at startup to cure the problem.
The top three culprits would be MAFS, Spark Plugs, and O2 sensors (4). I would replace all three of those first and see if that solves your problem. If not then at that point you must dig deeper and spend more $$$. Unfortunately $tealers are the same world round! Clueless Keep us posted and good luck!
Well, this is a dummies question; the O2 sensors; is this the sensors located just before and after the catalysts?? Honestly; I don't know...
The hesitation of the cold engine has "always" been there, it's just less noticeable just after I replace the MAF's.
But thanks for the tips; I will check'em up!
Suggestion: My car has had a hesitation when cold since new (there is a slight hill about 100 yards from my house where it shows up). I used to wait to turn the Sport button ON until it warmed up. Now, I set Sport ON immediately and NO hesitation. Never any hesitation anymore (46,000 miles).
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"The greatest obstacle to discovery is not ignorance; it is the illusion of knowledge."
Keep us posted and good luck!
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