Misfires after engine cleaning

Hey guys. New to the site and posting on a phone so it's hard to search. I recently cleaned my engine(99 540/6). I followed procedure and covered all electrical connections and the alternator. I sprayed engine brite on, let stand for 15 minutes, then sparingly misted the entire compartment making sure to stay away from those connections.

I let the car dry for a day, then drove it 3 times in 2 days, with it running great. Then I came out and started it, and got rough idle, coughing, stalling and CEL. I read the codes and they are misfire codes w/ fuel cut off for cylinders 3,4,7,8.

I popped the ignition coil covers, and their was no pooled water; however everything was damp. Since they are cheap, I was going to replace the spark plugs and boots for those cylinders and see if that cures my problem. If that doesn't work I'm guessing the next logical part would be the coils. Is their anything else that could cause my issues, and is my first course of action a prudent one?

Thanks for the help!

Originally Posted by DK540

Hey guys. New to the site and posting on a phone so it's hard to search.

That's not a great way to start off your first thread on Bimmerfest.

I, for example, have an Android phone and I have no problems doing searches (on my computer).

I haven't actually tried searching on my Samsung Galaxy SIII, so, may I ask the specific question:
QUESTION: What is the problem with searching on a smart phone anyway?
Do we need a special section in this thread on how to do searches on smart phones?
How To Easily Find Information on Your E39 Topic Before Posting a New Thread

Cylinders 3,4,7 &8 are the rear four cylinder. Maybe you got water in the plug holes. I'd pull the coil packs and check for water/damp above the plugs. I wouldn't remove the plugs unless your sure it is dry in there, as removing plug would let any water drain in to the cylinder.

If there was water in there might have blown your coil packs. The test for that would be to move one of the indicated coil packs to a working cylinder and see if the fault code moves with it.

Dont know what the "procedure" you refer to is.. but you got it wet... and its still wet..

next time... clean the engine hot... and let it idle for a while after its done... dry the engine with its own heat...
thats how we do it at the shop

Thanks for the replies! First off, I did use the advanced search with "misfire" clearly in my search terms, and came up with 2 threads. One was all BMW code #'s and the other was for an e34 that had multiple misfires, but had nothing to do with the engine being wet. So, sorry if I made it sound like I simply wasn't going to search. I did.

Well, I removed the rear 4 coils and boots, and dried everything thoroughly with a blow drier then reassembled. I took it for a short drive and it ran fine, but still had a CEL. I turned it off for 2 minutes, then back on, and the problem returned. I won't have access to a scanner until tomorrow, so I will try moving the coils and report my findings. Thanks again!

your chaseing a ghost... If the car runs... and will idle... let it idle for a few hours
Or drive it till it clears...
Its wet.

Why did you let it sit for so long after rinsing it? I dont know about cleaning a hot engine with cold water, but I do know that I use engine brite often and everytime, spray the cold engine, let it sit(5-10 min) and rinse. Then start the car and let the fan and engine heat dry everything out for a few minutes, take it for a drive to operating temp and with the hot engine closed up under the hood let it get the rest of the moisture out.

Originally Posted by Burning2nd

your chaseing a ghost... If the car runs... and will idle... let it idle for a few hours
Or drive it till it clears...
Its wet.

I think you may be right. I started it this morning, and it idled fine, so I took it on the highway to see how it acted, and I'm still getting intermittent misfires, but it seems to be getting better as it's happening less often. I'm gonna hold off on the new boots and plugs for the time being.

One question. Will I need to get the CEL reset, or will it go away once everything is completely dry? Thanks again!

engine cleaning = looking for a trouble
let it dry , you might be lucky

Originally Posted by champaign777

engine cleaning = looking for a trouble
let it dry , you might be lucky

It appears as though I may have gotten lucky, because the misfiring has stopped completely. I stopped by my Indy to pick up some parts I needed, and had him reset my CEL. It has run totally fine since then and the light has not come back on.

Thanks for the help and replies!

theres nothing wrong with cleaning engines... you just have to know how to do it..

And hot engines and cold water are not a problem

It has no effect... the point is the engine is warm it will dry quickly

Originally Posted by burning2nd

dont know what the "procedure" you refer to is.. But you got it wet... And its still wet..

Next time... Clean the engine hot... And let it idle for a while after its done... Dry the engine with its own heat...
Thats how we do it at the shop

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