fordsportjay

iTrader: (6)

hi guys

i have a bit of a running problem with my e36 m3 track car.

i have done 12 or so track days in this car and it has never missed a beat with just regular oil/plug changes.i drive it really hard and it loves it....

on one of the last trackdays ive done it begun to feel a bit "flat" and not as happy to rev as it usually is. then the last time out it got a lot worse.

i put my scanner on it and the fault was air flow meter and another for oxygen sensor 1. i have put a new afm on it and it is now idling nice again but it still has the flat feeling.it has had 2 new lamda sensors while ive had it.ive also noticed that it has no in line fuel filter,just the gauze on the fuel pump which is making me think it may be some dirt in an injector or something......

does any of the bmw boys know which oxy sensor no 1 is-mine only has the 2 pre cat ones fitted as its been decatted,is it the n/s one or the o/s one?

my scanner isnt reading any misfires,but if you unplug a coil unit it reads a misfire so i dont think its a plug/coil problem.

its getting frustrating now as its not a road car so i cant just run it up and down the road....may just book it in at my local rolling road to see if anything comes up.

any ideas,anyone?im thinking to fit 1/2 new oxy sensors and get the injectors tested/cleaned and fit an in line fuel filter....

Harry.

Are you sure it doesn't have a fuel filter? I couldn't find mine until I looked in the Haynes manual - it's underneath the inlet manifold by the block iirc. That said, I'm not sure whether it's 'in line' or not.

fordsportjay

iTrader: (6)

i havent seen a fuel filter.i think the m3 one is a long one that sits along the floorpan towards the front of the car.....
what has got me thinking is the car is originally a 320 coupe with all m3 running gear fitted- all done way before i got the car and converted it into a track car.ive never had to touch the engine apart from servicing as its been so sweet and reliable

Harry.

Well mine's a M50 engine (325i), I'll go take a photo of the fuel filter. I've just done a search and I don't think the M3 filter position differs between e36 models.

Harry.

Apologies for the shoddy iPhone camera quality.
Red arrow: Filter
Blue arrow: Filter shield thing which blocks it almost completely from sight.
http://img149.imageshack.us/img149/2...lter002jh2.jpg

And this is what it looks like out of it's element:
http://img177.imageshack.us/img177/9...lter001uu6.jpg

Alexc-t

On my P reg 320 the Fuel filter is under a cover on the passenger side of the car.

EDIT: pictures of it shown here http://www.bimmerfest.com/forums/sho...d.php?t=336489

TWoods

bank1 is the first 3 cylinders, bank2 is last 3 nearest the bulkhead.

tps sensor maybe full of oil take it off spray with brake and clutch shake like mad and drain and refit

doubt an injector problem otherwise will run bad all the time, a recirc valve under inlet maybe fouled should hear a mini dump valve sort of noise just after turning engine off also another common problem nobody ever fixes but common cause for flat spots.

C4llyT

On M3 is underneath, can't miss it nearly as long as car - but not starting out as M3 could be elsewhere if 320's had them situated differently?

Any of these track days been pretty wet?
My lambda connectors keep filling with water, both new from bmw, had to seal the boots properly.
Only an unscrew to check.

I'm sure you know some diagnostics miss things, autologic is what you want.
Cam sensors are always a favourite, but 3 of them.
Otherwise TPS, which is cheap enough anyway, and an insp2 item, or should be.

Harry.

I wish mine was there! Mine's pre '94 which must be why it's not.

AlexF

Is the VANOS quiet?

fordsportjay

iTrader: (6)

ive just realised that i have only changed one oxy sensor while ive had it.the other one is an aftermarket one that doesnt have the original plug on it anymore.

im going to change this first before i go on.....

Steven_RW

I was told my E46 M3 couldn't be de-catted as the ox sensor after the cat would know that the gas hadn't changed, decide something must be knacked and go in a limp home mode.

Is that not the case with u?

RW

C4llyT

Pre cat so doesn't change anything.

Childsyxxx

If there is an ox sensor after the cat position i wouldnt adise de-cattin, creates all sorts of questions for the cars ecu and itl adjust all sorts of mixtures to try and get the exhaust gas mix wat it would consider correct, hence giving the poor performance maybe be running very lean to try an change the exhuast gases because it dosnt knw the cat has been removed.

fordsportjay

iTrader: (6)

the car has run fine as it is for about 12 hard trackdays.its just developed this problem out out of the blue.there are only sensors on the car now,before where the catrs would have been,

ive just fitted 2 new oxy sensors as the only real fault code coming up was 02 sensor1.

but ive just had it running with the scanner connected for live feed and if i clear the fault codes it starts and runs no problem and if you go through the live info there is 02 voltage to either 02 sensor. if you go down to the 02 sensor integration percentage it climbs steadily(both) until it gets to about 30% when you can hear the car go slightly lumpy and then when it gets to about 38% on both,no 1 just drops to 0% and the fault code comes up-oxy sensor no1. and just after no2 integration drops to 0% but never comes up as a fault code on no2 sensor?

im a bit out of touch now due being lazy and spending too much time driving selling cars rather than working on them.........

does this suggest anything to anyone ecu/wiring etc?????

its getting rather frustrating now.

AlexF

o2 sensors are dead...

fordsportjay

iTrader: (6)

im presuming its not the sensors themselves though is it?

what can i check?

AlexF

It sounds like they are...

If you can see what the o2 sensors are doing by reading the ECU - then that says the ECU, wiring and the O2 sensors are connected and doing somthing....

Alex

fordsportjay

iTrader: (6)

but why are they showing no volts at either one?
there is a black box ecu above the silver ecu and it seems that the lamda wiring goes into this unit.
it also looks like it may have an aftermarket chip fitted?

AlexF

To see whats happening you need to scope them really...

Have you decatted the car?

fordsportjay

iTrader: (6)

the car has been de-catted but it was before i bought it.i have done about 12 trackdays in the car and it hasnt missed a beat and revs very freely.its only started happening on the last 2 trackdays where its gone flat.

ive found a receipt for a "chip" for Ł170. im presuming this may be a plug in chip.if so do they plug into the main ecu with the huge plug or into the one above it which has a much smaller white plug on it with about 20 or so wires as this one looks like it has a chip fitted(like on a cossie) which would plug in and it has a sticker with some hand written stuff on it that i cant really make out...

fordsportjay

iTrader: (6)

if i run the car,what readings should i see at the wires-
the heater wire,signal wire, etc

Jim Galbally

3.0 is a chip replacement inside the ECU ala cossie.

you can get a proper ECu reader thing to display all the live readings on them as theyre OBD so you should be able to easily tell if theres a sensor fault when you watch the readings live.

i was once told that the O2 sensors share the same +12v as the MAF, so worth double checking if theyve lost their +12v and that the MAF is ok? (i was told this by a garage that proved to be SHIT tho)

fordsportjay

iTrader: (6)

does anyone know which wire on the sensor wiring should be which?

ie which 2 are the heater oones,which should be the signal wire and which colour should be earth.
its been fitted with aftermarket ones before i got it so no oe plug.

ive just had the meter on it and with it idling the supposed black signal wire is showing battery voltage,the grey ground wire is ground and the 2 heater wires are 0.12 v.
the colour wires from the car are brown,blue/green,black and yellow.

Jim Galbally

ive heard that the non-OE sensors are dogshit and fail. would you be happy to just change them for proper ones as part of the diagnostic process?

davidreader5

but ive just had it running with the scanner connected for live feed and if i clear the fault codes it starts and runs no problem and if you go through the live info there is 02 voltage to either 02 sensor. if you go down to the 02 sensor integration percentage it climbs steadily(both) until it gets to about 30% when you can hear the car go slightly lumpy and then when it gets to about 38% on both,no 1 just drops to 0% and the fault code comes up-oxy sensor no1. and just after no2 integration drops to 0% but never comes up as a fault code on no2 sensor?


By What you have wrote above, based on normal narrow band 02 sensor, it sounds like you are describing the 02 function inc fuel trims short & long, or maybe just short as you have no 02 sensor after the cat, and it seems you have a table of 30% -+. and sounds like the trims have reached there limit, positive trim means the ecu is trying to correct for a lean condition, and negative trim for rich condition, see what the average voltage is of the 02 sensors, if rich try the cts, as you have already replaced the afm, the other thing is does your kit show the status of the 02 sensor, such as closed loop.

Regards Dave R.

Jim Galbally

if the O2 sensors are not reguistering a fault throwing it into LOS and its still flat on WOT, then the issue is not O2 sensor related (as it ignores them on WOT). the only labda related thing that would cause flatness on WOT would be if its in LOS

AlexF

Black and Yellow are the heater
Brown is ground
Green is signal

iirc

fordsportjay

iTrader: (6)

if the above is correct then i think they may be wired up wrong.ill have to check tomorrow.

fordsportjay

iTrader: (6)

the scanner im using an old snap on one.

with the car running and the fault code "o2 sensor1" cleared.you can scroll down to what all the snsors are doing whilst its running and the voltage for both 02 sensors 1 and 2 are zero volts,which surely isnt right.it was like that with the old sensors in too.

further down the info on the scanner whilst the car is running is the o2 intergator % (or something like that) if you watch them from start up both 1and 2 build up to about 30 or so percent then no1 drops to zero and then no2 does the same and when you scroll to the top the o2 sensor1 fault code has reappeared.
as you watch the intergator info on the screen you can hear the car begin to idle roughly as it approaches 35-38% then it smooths out once they drop to 0%.

the car did have a fault with the afm last trackday as it kept coming up on the scanner but now ive replaced it with a genuine one that fault code no longer comes up.

AlexF

Let me double check and try and get you a wiring diagram...

fordsportjay

iTrader: (6)

thanks alex,i appreciate it.

its really pissing me off because the car has been so reliable for the last year or so and has took everything ive thrown at it.
just feel like stripping it......!

AlexF

LOL its only somthing minor

Get it to bedford a ticket is yours for 100 quid

fordsportjay

iTrader: (6)

no point me comitting to any trackdays until its running right.

Childsyxxx

**Sorry about the long post**

Ok i understand it has two sensors, it would be rather odd to have two before the cat ??

I think that before the cat + manifold and downpipe were removed they would have been spread further apart, i.e one before and one after the cat's position as i cant see why they would place 2 right next to eachother.

That also would be why it runs fine upto a point, after resetting the faults it has no memory or recolection of the previous events, so it thinks the car is starting up for the first time (from cold) now with the cat in the car it would take a few minutes for the cat to warm to normal operating temperatures of between 700 - 1000 degrees celcius. after those few minutes (would it would useually consider the warming up period) it starts to think about why the readings aren't changing and automatically thinks the cat is faulty (or in this case missing) so itl adjust the mixtures to suit i.e the rough running you were talking about.

I dont think its faulty sensors, its unuseual for things to break at the same time, and they are reading the same so i wouldnt say it was them, plus you said in an earlier post you ahve just replaced them recently.

Try and find a standard manifold + cat and downpipe etc
Reset the faults trying running it take it for a drive etc


Hope this helps

Jim Galbally

childsy, its a 6cyl engine and runs 2x 3 port exhaust system. the 2 lambdas are one in each bank

Childsyxxx

thanks for that lol no1 said before, wouldve been a good theory if they wernt in that configuration :P

AlexF

Hello mate... Can you confirm what engine loom the car is using...?

M3 or 320?