My wife's 2002 325i was fine when she came home last night. This morning, it
starts readily, but surges between 500 and 1500 rpm every two seconds or so for
about thirty seconds, and then settles down to surging slightly around 1000 rpm.
It will not rev any higher, and makes no useful power. The "check engine soon"
and "ECN" lights are on.
Has anyone seen this behavior?
It has been flat-towed to the dealer, but they're so backed up that we won't get
it back this week. I'm interested in anyone's relevant experience to use as a
cross-check on whatever diagnosis they give us. TIA.
Sorry to have to tell you this (it happened to me as well) its the
engine management module, or whatever it's technical term is, ie the
computer and the unit needs to be replace. I was lucky and got it paid
for on the warranty. Can't recall the cost but it was hundreds of
Don't be so hasty; it could be a number of things other than the ECU.
For instance, it could be the crankshaft position sensor. It could be
a plugged catalytic converter. It could be a cracked intake hose.
It could be a new mouse nest in the air intake.
It could be that the battery needs to be unplugged for a few hours to
completely reset the ECU and anything else needing battery power. Give that
a try and see if it works. Couldn't hurt and may save some money.
Bill on Omaha
I always thought that this was an urban myth until I left my 320i garaged
over winter and when I opened the bonnet to check the oil etc I found a
little nest and pile of seeds between the suspension turret and the fuse
Oh no. Far from any sort of myth, but more likely rural rather than
urban, don't you think?
I get problems from the wee rodents all the time, even on vehicles that
don't sit more than a couple of days between uses. Watch for telltale
signs in the blanket they put up over the engine on the hood (bonnet)
for sound proofing. The rascals seem to really be keen on burrowing up
in there first. Maybe while the engine is still warm?
In fact, here's a funny story. I have a '98 Honda VFR800 that I picked
up used last summer for a song. It had only ~12k miles and ran like a
dream. Nary a problem. I decided that since the bike had unknown
maintenance performed by unknown prior owners and unknown storage
conditions, I would do everything that should have been done in the
first 12k miles and start my maintenance schedule afresh.
When I pulled off the air box cover to put in a new filter the upper
part of the box was jam packed with all sorts of mousey detritus. Empty
acorn shells, hay, mouse poop, you name it... The best news was that
even though the rascal(s) had also been ingesting the paper from the
filter, they has not breached it entirely and so none of the nestings
had been ingested by my engine (yet). Phew...
In my powerboat, I put several old cigar boxes full of mothballs in the
boat before I seal it up tight with shrink wrap for the winter. I've
never had a single sign of mouse activity in there after 5 years of
winters. In fact the boat smells of the balls well into the summer.
Well, got the diagnosis today, *one week* after having it towed in: electronic
throttle failure, to the tune of $1511.00 US.
The service agent said the fail-safe mode of the electronic throttle allows
revving up to 2K, but if you try to go over 2k, it shuts the engine down --
which is not the behavior I was seeing.
Then the advisor tells me the car needs level one service (done two weeks ago),
and new wiper blades. Of course, I put brand new PIAA silcones on there about
three weeks ago, so that's a clue as to how straight this supposedly top-notch
BMW dealer is. 8;)
This is a 2002 325i with 34,000 miles on it. Has anyone heard of electronic
throttle failure on a like car, or of any attempts to get BMW to eat some or all
of it out of warranty?
Thanks again -- Larry
OMG. They could have told you that for a few minutes and an OBD2 diag
machine. My BS flag would have gone off at that point. Just a guess, but
this is not a good showing for the shop it went to. (sprinkle in some choice
Bill in Omaha
From the sound of it, I'll bet they didn't give him a code at all
and if he asks they'll just give him the one that matches their
diagnosis. A decent mechanic would have tested this right away as he
would have recognized the symptoms. This shop would not be working on
my car as they've already lied about work needing done. I may have
missed the original post but whatever is actually wrong is most likely
a simple matter that they're looking to cash in on.
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