Radiator busted, now misfires on cylinders 5 & 4

[80stech]

A bad injector will often not be obvious with measuring ohms so if that doesn't work switch places like you would with a coil if you haven't already.

Was compression test 4 strokes only? Have you put new spark plugs in? Do you have a cooling system pressure tester ?

[jac]

Thank you all. I did measure the resistance on the 6 injectors:

Injectors 1, 5, 6: 11.8 ohms
Injectors 2, 3, 4: 11.7 ohms

I just swapped injectors 2 & 5. Going for a ride.

The compression test was 6 strokes. I have not put in new spark plugs, but have swapped the spark plugs and the coil positions and that did not change a thing.

Yes, I got a cooling system pressure tester kit a few weeks back. I have not used it yet. Gonna do that, anything I should look out/do for that?

[80stech]

Any updates ? The idea behind the cooling system pressure tester would be to check for a head gasket/crack issue.

[jac]

I cleared all the codes and adaptations using INPA, and left the car running in the driveway for like 45 minutes.

I was in the car for those 45 minutes, trying to find out how to log RPM, throttle angle, lambda trims, cylinder roughness, and VANOS on INPA, but I did not find anything. :-(

While I was sitting there, I noticed the following:

- The engine turns on without any issues
- The yellow trifecta is ON (Triangle, ABS, Brake)
- I turned the steering wheel all the way left and right several times, but no effect on the trifecta. This also started happening after the radiator issue, and I noticed that the lights usually change to yellow Triangle and ABS, but red Brake warning light, after driving.
- While it warms up, the engine sits at around 750 RPMs
- As the car is warming up, the engine stutters every few seconds. The RPMs go down briefly to almost 500, and then the engine quickly normalizes back up to 750. It does this until the temp needle reaches the top half of the blue marker in that gauge.
- After the gauge moves past the blue zone, the engine purrs like a baby. It is super smooth.
- It sat there for 45 minutes (while I looked through all the INPA screens) completely steady. At this idle, it sits around 700 RPMs.
- It did not throw any codes while it sat there idling.

I have not driven it yet as I have been busy at work and am still figuring out what to use to log that stuff I listed above. Someone recommended a software called TrustO, but the laptop I use for the car is too old (WinxP), so I gotta figure that out.

[80stech]

There should be codes if there is a trifecta. I wouldn't be too worried about logging stuff. Drive the car to get the misfire and then DME will actually log conditions (INPA codes detail section) when code sets, but I doubt that is going to help you very much.

[X5chemist]

The trifecta will appear if battery voltage gets too low or battery is disconnected. As suggested, drive it for a bit until codes appear.

[80stech]

Yeah, I just re-read some of this and the OP already has a cooling system pressure tester, I thought it was ordered but must have been a different thread, so should be using that to verify the head gasket or crack instead of trying everything to pretend that it isn't. Also confusing is that INPA is talked about and screen shot is ICarly or something ?? Anyway, OP let the car sit overnight with pressure on the cooling system and plugs out then crank in the morning and watch if coolant comes out of one of the spark plug holes.

Side note-- Any time you swap around parts looking for a misfire, especially when the DME has cut fuel, you should at least clear the codes to get the DME to retry the cylinder you are looking at or it might stay shut down and totally confuse the situation.

[jac]

Thanks folks. You are awesome!

The trifecta will appear if battery voltage gets too low or battery is disconnected
. Thanks. After driving for a few seconds, that trifecta changes. It goes to yellow triangle, yellow ABS, but red Brake light.


INPA vs screenshots of something else: My apologie for that. I always look at the error codes on both INPA and PA Soft BMW Scanner 1.4. The screenshots are from the PA Soft, I prefer those for my records, as the ouput of INPA is in German. But, for whatever reason, I trust INPA more.


Head gasket or crack instead of trying everything to pretend that it isn't: Yeah, you are right. It's just that I thought maybe these other tests could point to that as well or rule it out. I will go learn how to do the cooling system compression test.

let the car sit overnight with pressure on the cooling system and plugs out then crank in the morning and watch if coolant comes out of one of the spark plug holes.. So, in the morning, I just crank without the spark plugs out of the head?

I drove it just now and was able to log some data (see below) with another tool I have. The problem remains on cylinder #5 (but it only came out after hard acceleration) even though I had swapped the injector as well. Anyway, I will go try the cooling system checks and report back. Likely won't get around to it until Sunday.

Thanks folks!

[80stech]

Putting new plugs in will probably make it go longer before the miss comes back. Yes, put pressure on with the pressure tester, let it sit with spark plugs out, and then crank the engine to see if coolant comes out of one of the holes.

[jac]

I just did the cooling system pressure test. Connected the hand pump and applied 15 psi to the system. It has held that pressure so far for the last 30 minutes.

Edit: 2 hours later, it is still holding 15 psi.