Re: 94 840ci all show no go (archive)

:Hi , I had a '95 840Ci and wasn't slow at all ! Here is my advice :
1. Check the compression ratio in your engine !
You still got 20k miles left from the
warranty. If the engine block fails due to
high sulfur doesn't always smoke !
If it is lower then a factory numbers then go
and ask the stealer about the procedure of
engine replacement under warranty
if that's not the case then ...
2. Go to the dealer and ask them to verify the
chip , is it the latest or not. I did have a
problem with a latest chip (Check engine
light, rough idle, etc) so they had to put
the "old" back. They won;t give you an older
chip, but they might give you a better one.
Also while testing the ECU, make sure all the
spark plugs are good, and the ignition modules
are ok too. The test computer will show any
ignition problem.
3. Check the transmission chip also, maybe the
transmission is shifting too early, etc.
4. Check the O2 sensors ! If they are clogged,
they can detune the car !!! You are lucky
because there is only 2 in your car !
After '96 there is 4. Take them out, if they
have a black residue on the top part, clean
them with carb spray or buy a new set. It
should be also visible on the test computer
for the dealer !
5. If they find everything in order and new spark
plugs are installed, then try an aftermarket
chip.
BTW : What do you mean no go ? How is the acceleration from 0-60 ? It should be around 7s and top speed 138mph. What is your average mpg ? it should be around 16-18mpg with normal average driving and around 14-15 with a little heavier feet. If you are pushing it, it should be under 13 but I never had under 10 unless I floored it all the time. So this is an important factor, beacuse if your car is using a lot of fuel and still no guts then it most likely an O2 sensor or catalic converter problem !
I think this is enough testing for a week, and let us know what happend !
Wish you good luck,
By : Lez

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