e85 2.5 auto cold start ‘Injector Cylinder 3’ misfire troubleshooting.

[timwwells]

Evening all,

I’ve done the obligatory search far and wide for this and found inconsistent troubleshooting advice/solutions so wanted to put it out there for advice before I take next more expensive steps. Hope perhaps it helps anyone else going forward with similar issues.

Car:

2.5 e85 auto with 94k

Symptoms:

When cold and with first start, can hear a misfire, revs/runs lumpy, with little power. Have the check engine light on and Carly reads ‘0027A8 Injector cylinder 3’. As soon as the engine temp gets out of the blue, I can turn it off and back on, and it runs perfect for the rest of the day, even if it is seemingly cold again. Engine light also goes out.

What I’ve done so far:

New spark plugs, swapped cylinder coils and no change. All been cleaned and checked for fitting. Have noticed some light oiling in cyl 2 spark plug well. I have the common old age m54 minor oil leak which I’ll be sourcing and sorting when I can determine what else I take apart to fix the cold running issue. Have an injector on standby to change it, but can’t take it back after I’ve installed it obviously if it doesn’t fix it- lots I’ve read points that this could be an issue elsewhere. I can’t get my head around it being an injector if it runs perfect after warm if anyone can explain the logic past my diy YouTube experience/knowledge!

Various things is could be from trawling the web:

Wiring
DISA valve
Vanos seals
Just the injector.
Something to do with ecu?

Any advice or similar experiences/fixes are very very welcome. I’m pretty handy with mechanics etc with cars. This last week or so have: renovated headlights and fit new rear caps, stripped entire interior out replaced carpets and boot lining, door seals, drivers door membrane, replaced and relocated roof motor, done all four springs this last week. On to the engine next but want to do it in one hit and get all the parts I might need ready.

Thanks in advance!

 

[Scooba_Steve]

Why not swap an injector over, to rule it out?

 

[colb]

Like swapping the coils over between cylinders you could do the same with the No3 injector with one of the others and see if it sets a code for another cylinder ie see if the fault code moved with the suspect injector. If it is at fault replace it and test again after clearing the codes. If you are seeing signs of oil in a plug well thats a good indication of the centre plug well gaskets have gone hard, maybe cracked with age and allowing oil to get into the plug well. A leak anywhere in the cam cover and centre plug gaskets will also allow unmetrered air to get sucked into the engines vaccum system which will upset fuel trims and cause rough running as the computer will try and correct what it sees as a weak mixture and keep adding fuel at the injectors. If it has an air leak it will add up to 20% more fuel until it gives up and sets the EML on the dash. If you replace the cam cover gaskets get a kit that includes the round rubber seals that fit under the cover retaining bolts, these should be replaced with the new gaskets as they go hard and can affect torquing the cover down correctly. Also use some gasket sealant only around the half moon shapes at the front and rear of the cover where the gasket changes direction and between the vanos, no sealant needs to be used on the rest of the gasket, the ridges in the material will provide sufficient sealing with the new under bolt seals being renewed. A smoke test can be a good test to see if you have vaccum leaks across the engines vaccum system if you can't find them visually. Air leaks are a common problem on BMW's and can upset other sensors which can lead you to replacing parts that are not at fault.

 

[timwwells]

Thanks for the responses both.

Thoughts with just swapping the injector is firstly the time to take it apart and swap, and secondly I am under the impression they are coded on these so may not run right anyway? Will have to take it to a garage for that a so only have Carly. Willing to do the time if that’s not the case.

Great to know the impact of the oil leak/air ingress. I’ll order a rocket gasket with the plug gaskets and get on that. I have a feeling a previous fix has been done with gasket sealer so want to do a tidier job of it anyway. Where else are there likely oil leaks as if I’m doing one or some I might as well replace them all along with an engine/transmission oil service.

Thanks again.

 

[timwwells]

Seems my sources for parts have the retaining bolt gaskets separate. Can you help with how many are needed?

Tim

 

[timwwells]

Have replaced rocker gasket... and rocker cover as it had a break in it. Still misfiring on cold start

Have swapped coils and no change in cylinder reading. Guess I’ll change the number 3 injector next.

Any ideas for fault finding next?

 

[Jamturbo]

Hi,

I had a lumpy start problem. Did the usual checks you have done. Have you considered the breather plastic hoses or MAF. Good luck.