Anyone with an M43 motor and a diganostic tool?

[Zephyr]

So… checked a friends M43 today and the results were 1- 0.76 2- 0.87 3- 2.13 4- 0.28
quite puzzled I visited my local tech and asked about this pattern with the third cylinder so he got also curious and used his official Scanning tool to measure my car.
the third cylinder was constantly over 2.10 and everything else (lambda, maf, etc) was within spec.
he had no idea why this is happening so he opened a ticket to the bmw central as he also wants to understand this.
i asked him how come and he hadnt noticed such a behaviour in the past and he said that he rarely cares about smooth running values and he just fixes whatever error the ecu directs him to, not considering these numbers as something that raises any alarms unless he sees values over 7 or more.
in general he said six cylinder are the smoothest and four and eight cylinders tend to have some differences between cylinders or banks of cylinders.
nevertheless we are waiting for the official response if any.
still I am not satisfied with this, I think that the values have to be equal… why the third cylinder is so much off can only lead me to a faulty camshaft since I have so far made a compression test, a smoke test, changed wires, sparks, vacuum hoses, intake and idle valve and coils… unless this is the design of the engine….

maybe I will never find out and have to live with this “gulp” while in idle….

if anyone even with a six pot would like to get into trouble and share some numbers please do.
thanks for not yelling at me, I think my ”smoothness“ syndrome has taken too much of this forums space already….

 

[Jam03]

minus 5? So sorry…..
View attachment 247275

You are evil…what kind of cake is that?

 

[Zephyr]

You are evil…what kind of cake is that?

It was orange with chocolate… delicious.

 

[Zephyr]

Official BMW answer:
Any deviation over 10% between cylinder running values is considered abnormal and needs to be checked.
please refer to Technical troubleshooting ver. Blah blah blah, that points out to pretty much to what I have done so far, even my spark plugs are torqued to spec, so… i give up.
it drives well except that idle “gulp”.
I can not deal with this any more, it has taken too much if my time.
sorry for being so persistent with this, I will not bother you any more.

 

[Stevo7682]

Have you tried swapping the no3 injector to a different position to see if issue cganges cylinder.
Stephen

 

[Zephyr]

Yes. Swapped the injector no3 with No1 and even took them at a shop to have them checked. (Along with the fuel rail - that has no leaks). Plugged them back with new o rings and new breather hoses (oem ones).
then swapped the wires, 1 to 3 and then 4 to 3, with out any change.
the sad thing is that for a while the engine worked at an even 0.83 to 0.88 to all cylinders and then one day it decided to do its funny stuff again and stayed this way.
smoke tested, compression tested, inspected with a micro camera, changed - icv, all hoses, cleaned throttle valve, checked disa (although in idle it does not affect the engine), changed breather valve…. Almost everything regarding fuel (oh also changed fuel filter) and spark with all paraphernalia is brand new and either oem or bosch branded.
I suspect valve lifters, or camshaft…
But again why only cylinder 3 and why on M43 engines?
If this car wasnt so pristine, well maintained and documented and had not earned a grade 1 youngtimer certificate, a 3.0 M54 would already have taken the place of this anaemic 118hp piece of crap.
or maybe I will keep this in the garage, sell my E21 and get another Z3 to play dr Frankenstein with it and make it a real monster.
Dont get me wrong, it is a very very good example of a Z3, titan silver, sport edition, unmolested, parked in a garage for years before my ownership, and the only thing that bothers me is that I can not sort something that if I hadnt scan it for running values I wouldnt even know that exists as an issue.
sometimes I gues you have to be satisfied with just what things are and do not try to reach perfection….

rant mode off.

 

[Jam03]

Yes. Swapped the injector no3 with No1 and even took them at a shop to have them checked. (Along with the fuel rail - that has no leaks). Plugged them back with new o rings and new breather hoses (oem ones).
then swapped the wires, 1 to 3 and then 4 to 3, with out any change.
the sad thing is that for a while the engine worked at an even 0.83 to 0.88 to all cylinders and then one day it decided to do its funny stuff again and stayed this way.
smoke tested, compression tested, inspected with a micro camera, changed - icv, all hoses, cleaned throttle valve, checked disa (although in idle it does not affect the engine), changed breather valve…. Almost everything regarding fuel (oh also changed fuel filter) and spark with all paraphernalia is brand new and either oem or bosch branded.
I suspect valve lifters, or camshaft…
But again why only cylinder 3 and why on M43 engines?
If this car wasnt so pristine, well maintained and documented and had not earned a grade 1 youngtimer certificate, a 3.0 M54 would already have taken the place of this anaemic 118hp piece of crap.
or maybe I will keep this in the garage, sell my E21 and get another Z3 to play dr Frankenstein with it and make it a real monster.
Dont get me wrong, it is a very very good example of a Z3, titan silver, sport edition, unmolested, parked in a garage for years before my ownership, and the only thing that bothers me is that I can not sort something that if I hadnt scan it for running values I wouldnt even know that exists as an issue.
sometimes I gues you have to be satisfied with just what things are and do not try to reach perfection….

rant mode off.

You need some M54 in your life for sure

 

[Zephyr]

You need some M54 in your life for sure

Maybe I can swap an M54 to the E21.
then find someplace to stay after the divorce and finally die a noble death in my garage hanged from the ceiling with the engine harness…
Another brilliant idea….

 

[Stevo7682]

Thats a shame that after all that you still have an issue.
My 99 m43 runs nice and smooth at 123k miles i can leave it for months and aslong as battery good it will start in a few turns and purr away like it had been running the day before granted the 118bhp is not the greatest thing in the performance world with decent suspension they are pretty sharp in the twisting roads they have a better weight distribution so resist understeer better.
I have heard the cracked cylinder head stories but you can guarantee poor maintenance will be behind most of them .
You have looked into pretty much all the common issues vacuum pipes being really high on that list .
M43 would be fairly straightforward to swap out not that big a unit especially in a z3 with an engine bay big enough to carry a 3.2 straight 6.
If car really nice would that be an option and can you pick up a 2nd hand engine locally for decent money.
Stephen.

 

[Zephyr]

Many of my friends suggest an Italian tuneup, drive it and rev the hell out of it until it empties a full tank. Maybe as a last try, I will do this, although it is not “in me” to drive this way… we will see….

 

[Jam03]

Many of my friends suggest an Italian tuneup, drive it and rev the hell out of it until it empties a full tank. Maybe as a last try, I will do this, although it is not “in me” to drive this way… we will see….

I’m buying my ticket to Athens, it’s the least I can do.

 

[Stevo7682]

What fuel do you run it on standard 95 or super unleaded 98 octane .

 

[Zephyr]

bp ultimate 100 for the last 3 top ups. Usually 98 but tried this also. Bloody expensive over here…

 

[t-tony]

Yep, maybe an "Italian" tune-up is needed.

Tony.

 

[Zephyr]

Two more M43 scanned today, one german spec 1.9 with 105hp and one in an E46 but just a 1.6
data showed major differences between chlinder no3 (+1.2 more for the 1.9 and +2.5 for the smaller one).
so, this can not be coincidence, i am sure it has to do with the engine design, thus I will close this case, unless someone jumps in and gives some other explanation.
fyi, mine today with the maf of the 1.9 jumped to a jaw dropping 4.25 on the third cylinder, while my maf on that car eased things to normal but still showing a difference to cylinder 3 (0.79). So this guy has a maf that is about to die…