I have a 1994 530i that has been running quite well in the three years
I've had it. However, recently I've been having a bit of a problem.
The car idles rough and almost dies. Then it speeds up (ostensibly the
computer is giving it gas to prevent the engine from dying) and then the
check engine light comes on. After a short period of time the light
goes out and everything seems fine. This seems to happen only in the
morning and only when the engine is about 3/4 the way to its normal
operating temperature. It doesn't seem to happen in the afternoon even
if the engine starts out cold. Perhaps outside air temperature has
something to do with it. I don't have a tool to check the fault code,
so I'm in the dark as to what this might be. Any ideas?
Rule of Acquisition number 284: Deep down, everyone's a Ferengi.
Won't this car tell the trouble code by mashing the gas pedal 5 times while
holding your tongue against the roof of your mouth? Turn the ignition to ON
but not START, fully depress the gas pedal 5 times within 3 seconds and the
code is displayed by the Check light flashing.
I'm not sure of the timing on the depressing-the-gas-pedal stuff, so I
expect somebody will jump in here and dial that in for us ... (I am pretty
sure you have to hold your tongue in the right position though, or none of
this works ;-) )
The E30's had a test for this. With the air flow sensor feed
disconnected, slowly opening the trap door should reflect a
consistently changing resistance on a meter. The door should swing
with no rough spots or binding. You can look for something stuck in
there maybe. Good luck, that's an expensive part for some reason.
On 11/14/2007 11:54 PM, cosmo went clickity clack on the keyboard and
produced this interesting bit of text:
Yeah, tell me about it. $230 is the best price I've seen. I did some
research on how mass sensor works and apparently there are about four
different ways of doing it, each having a different accuracy. I think
that there is some data processing chip involved and that's probably
what drives the price up.
I gave my cat a bath the other day. He just sat there. Actually, I think
he enjoyed it. It wasn't very fun for me, though. The fur kind of stuck
No, in the case of the E30, it's just a vane with a pot. There are
two variants of the thing, one with five pins and one with six, but
the pot inside is pretty much the same.
It is possible to disassemble the thing, clean and lubricate the
bronze bearings, and clean the pot element with Cailube or Cramolin.
Most of the problems with these are caused either by the bearings
causing the vane to hang up, or with the pot developing dead spots.
If the pot wiper is worn out, you buy a new sensor box.
"C'est un Nagra. C'est suisse, et tres, tres precis."
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