Misfire Updated

[Steeler]

As a prerequisite to all I will write here, I have replaced coil packs ,plugs and injectors as part of the supercharger build.
I have driven the car only once this year because of the weather with no hint of a problem.
I installed a header over the winter and expected a CEL because of the O2's
I have removed the SAP and also rebuilt the Vanos over the winter using a Dr Vanos rebuilt unit.

So each of the last 2 mornings I have started up the car to pull it to continue an ongoing renovation to the garage
Yesterday morning on start up the idle was very rough but smoothed out within 10 seconds which I put down to it being cold. Upon starting up to put back inside the garage at night it did the same.
This morning the same but was about 20 seconds before the idle settled in.
Upon start up tonight the idle was very rough and did not settle and it produced a CEL. I pulled the codes and they are related to a misfire and a fuel trim
2743,2744,2745,2746,274E,2882 and 2883.
My thoughts
1 Could it be that the O2 sensors are so covered in soot from my over rich tune that they are not operating correctly but this was never an issue before
2 The removal of the SAP has something to do with it
3 The codes are pointing to cylinders 2,3,5 and 6 but not 1 and 4 which are the first and last in the firing order
4 I have the post cat sensors wired to the heat shield away from any combustible materials, could it be that these are the issue.
BTW my custom exhaust is on the shelf right now until a suitable muffler has been researched.The exhaust is stock from the header back ie no cats.

Just clutching at straws here as I am baffled.
I can build anything but the analytical side of my brain is not fully developed

[GuidoK]

Do you have very old fuel in the car?
Could be a fuel delivery problem (old fuel clogs up injectors, filter etc)

Can you post the actual obd2 codes?
2743,2744,2745,2746,274E,2882 and 2883 are not obd2 codes.
A misfire code is something like P0302 (misfire cyl2) and P0170 (fuel trim bank 1)
It is best to first wipe all codes, and then wait for the problem again and then read the codes. That way you know you only have the codes related to the problem.

It could also be related to a faulty sc install (vacuum or electrical problem) as you haven't really driven the car after that install. Is that correct?

Sometimes a (single) fuel trim code can be resolved by taking of the battery terminals and short circuit them (the terminals that is; not the battery . that way the ecu gets a reset)

[pokeybritches]

It could be a MAF sensor. Try unplugging it to see if it stabilizes out. Don't drive for long distances with the MAF unplugged, and know that the car will be more prone to stalling/limp mode.

[donoman]

^^ Yup, write down all codes, reset, and try again. Could still be related to your O2 sensors since that's part of the fueling circuit.

In my experience with BMW's, MAF's can cause all kinds of "down the line" CELs to pop up.

[Steeler]

Thanks all for the replies
GuidoK, yes they are not obd2 codes they are the proprietary BMW codes read by my reader, but the explanations are correct that I have noted
The s/c has been on the car for over a year now with no issues other than an over rich tune

Josh I will try the MAF,

BTW the car will not start at all now, just spins over and over.
I will check the pressure at the fuel rail to see if I am getting fuel delivery

[pokeybritches]

I'm not sure that it's O2 sensors if it's happening immediately upon startup. At that point, O2 sensors aren't warm and therefore not giving accurate readings. The ECU operates in an open loop mode, ignoring their readings until the sensors warm up.

[GuidoK]

That's about one minute that the ecu is in open loop, so no startup when cold is certainly not a lambda issue. If the lambda heater is at fault, it wil give an obd2 code.

I'd still like to see the real obd2 codes (beginning with P), just to rule out any faults.
It also is more clear if it's a general or manufacture specific code. I'm not going to translate the hexadecimal PID's.

A $10,- bluetooth dongle and some free smartphone software (torque etc) will do the trick for the generic P codes.

If your engine doesn't start at all and it is not in the fuel delivery (and your battery works fine), you're in deep shit, as you already changed the coils and plugs (no running but gas=no spark). Then you can only hope it's the coil's wiring harnass
Not starting at all usually isn't related to the maf (but running issues are often).

[Vanne]

Mate, do you drive the car much? If not that could be the issue, if it's been sitting around for a while, mine had the misfire code and a fuel rail code when I first got the car. Took it for a very spirited few drives with new fuel and gone are the codes...
That said, I did not have as many codes as you do..

[Steeler]

Originally Posted by Vanne

Mate, do you drive the car much? If not that could be the issue, if it's been sitting around for a while, mine had the misfire code and a fuel rail code when I first got the car. Took it for a very spirited few drives with new fuel and gone are the codes...
That said, I did not have as many codes as you do..

Thanks for that Vanne, not all doom and gloom.

I will check fuel pressure at the raill and if all is good I will remove the injectors and clean.

The reason I say that is because I have stored my "fun cars" through the winter since I was 18 and always made sure the gas tank was full before parking it.
This year the winter came on early and never left and I parked the car with a 1/8 tank of fuel expecting an indian summer that never materialized.
Chances are I have bad gas or sediment in the lines, injectors etc.
It makes sense that the idle gradually got worse to the point that it will not start and also that the codes thrown before it wouldn't start were only pointing to 4 of the cylinders.Basically it was running on 2 cylinders only.

[JeffchaPz]

OP this is what I think:

Bad gas
Possible bad MAF or on its way out
Bad pre cat O2 (s) or they are not connected properly or incorrectly.
Bad or on its way out fuel pump.

Buy a real time software or app for your cell to keep an eye on these things when you start the car and you might be able to get a better idea.


Good luck.

[Steeler]

Originally Posted by Vanne

Mate, do you drive the car much? If not that could be the issue, if it's been sitting around for a while, mine had the misfire code and a fuel rail code when I first got the car. Took it for a very spirited few drives with new fuel and gone are the codes...
That said, I did not have as many codes as you do..

Vanne you hit it right on the nose

Took the time to take out injectors,plugs and coils and swapped in known good parts that came out when the S/C was done last spring...no difference , no go.

Checked pressure at fuel rail it was all good.
Decided to top up the tank with fresh gas.
Caught on the 4th try and really idled rough, had to feather the throttle to keep it running, eventually it settled on a nice smooth idle.
Took her for a spin , the header and 3.73 gears combined really makes the car come alive and you really get pushed back in your seat when you hit 4,000 rpm.

Anywho lesson learned always top your tank up before putting your car away for the winter and I will now be adding a stabilizer to the tank.

[pokeybritches]

Some fuel additives work wonders. When I was driving through the middle of nowhere on my way home from Las Vegas a few years ago, the car suddenly stalled. I restarted it and was able to drive 10-20 seconds before pressing the gas was like pressing the brake (my guess is a clogged fuel filter). After a few iterations, I got to an exit and was able to pull over. I added a couple of bottles of fuel system cleaner and topped off the tank with premium, gave it a few minutes to settle, and then drove away with no further issues.

My dad majored in chemistry in college, and he explained how the additives are able to bond to water or whatever is clogging the filter, and pull the stuff harmlessly through. I don't remember the whole conversation because it's been years, but I do remember the additives worked.

[Steeler]

I know better than to put a car away for 3-4 months w/o a full tank but as I said this winter came and never left.
I won't count on an Indian summer ever again after the frustrations and heartaches this spring.