Cylinders 1 / 3 / 5 not firing

[newolde30]

Changed crank and cam posit sensors.
Grounded both sides of block to chassis.
Cylinder head grounded in 2 places with factory lugs.
Fuel rail grounded to tow hook.
Swapped working #2 coil into non-firing #1 location and it doesn't fire.
Changed spark at #1.
Swapped ECUs.
Checked wiring loom - all is tight.
needing some clues...

[DesertBMW]

injectors are known to get seized up if the engine was sitting for too long.

[newolde30]

i had these bench cleaned as part of the swap.
meant to say M50NV in my orig thread

any other thoughts?

[mpowerful]

Do you have spark at those cylinders? Its not clear from your description.

[newolde30]

yes i do - checked all 6 coil connectors and have steady current to all 6.
Yet even when i put in a known working coil from #2, 4, or 6 she still won't fire on that cylinder. i can tell because i disconnect the coil and it doesn't run any worse.

[mpowerful]

Put a spark plug in the coil and ground it and see if its sparking. This will tell you a massively importsnt piece of information.

[newolde30]

will do but i'm still confused as to why a known working coil from an adjacent cylinder won't work when i move it to either 1, 3, or 5? There is signal to all 6 coils!

[newolde30]

btw- just started it today. do i need to drive it hard to get the DME 'taught'?
it is running like crap on 3 cylinders though, and i;m not sure driving it would be good for it.

[mpowerful]

Well knowing whether or not it has spark can tell you if A) there is a problem with the ignition on those 3 cylinders or B) there is a problem with fuel on those three cylinders. It is important.

[DesertBMW]

Well knowing whether or not it has spark can tell you if A) there is a problem with the ignition on those 3 cylinders or B) there is a problem with fuel on those three cylinders. It is important.

All the guy is saying 3 cylinders are not working. This is not good enough to try to diagnose his problem via forum.

What are the compression numbers in those cylinders, if there is no compression then it won't fine, and we don't even know if he has ignition, pull the coil out and see if it throws spark.

[mpowerful]

^ thanks for the parrot impression. Very good hahaha.

[Poeman446]

Im having a similar problem with my E30 S52 swap. I pulled the injectors out, didnt clean them and havent really started diagnosing the issue. It runs pretty smooth on startup, but after heating up a little and after driving a bit it will develop a misfire in 1/3/5 and sometimes 2. I am guessing its my gas at this point because I mixed 87 and 93 octane in my tank. (im not a complete dumbass, I just figured that if I did mix my fuel my Octane rating would be high enough for the S52... Possibly not.... maybe i am a dumbass...) I cant think of any other reason that it would develop a misfire after warming up, but then again ive never really dealt with a misfire situation before. Ill be draining my gas and going to pure 93 octane as it should be, and running a can of seafoam through the tank. Ill update in a few weeks when I get back home. :/

[newolde30]

Fixed! 3 bad injectors. What are the chances they were #s 1 3 5?
That is why i thought it was electrical at first, but ETM gave no indication of a bank pref, so i took em out and put others in there, and now good to go. I never suspected them, as they were just bench cleaned and have not been used since.
thanks guys.

[DesertBMW]

Fixed! 3 bad injectors. What are the chances they were #s 1 3 5?

thanks guys.

But you said this:

i had these bench cleaned as part of the swap.

Before that I said this:

injectors are known to get seized up if the engine was sitting for too long.