I talked to Steve up at Bob's BMW about my ignition problem. He suggested going through my ECU connections and reseating everything.

Duncan mentioned I should use Deoxit contact cleaner on these connectors to clean them off. Looking on Amazon, however, there are various kinds.

What's the correct kind to use?

You want to go to or call Mark Electronics in Beltsville and explain your application to them--they should be able to suggest the appropriate variety (IIRC they only offer one or two that would apply to your situation)--or you can come grab my can. You might want to seriously consider dielectric grease for the critical connections as well--if I'm not mistaken, that's commonly used to protect critical connections on automotive electrics.

Duncan, what is the part# on the can you have?

I've used CRC QD Electronic Cleaner, which is a 4.5 oz. spray can. Seems to work fine without any harmful effects.

And I've got a tube of Permatex Dielectric Tune-Up Grease (85g), which has a fine, pointy spout allowing for easy application of small amounts. Also seems to do what it's supposed to.

I wish I could say that I had a problem and that these products solved it for me, but the problem that caused me to buy these in the first place turned out to be a broken wire and they don't fix that!

I have Gold G5 (flushing action)

There's also Gold GN5 (quick dry non drip)

and Gold G100 (no solvents)

My part number is G5S-6.

Awesome. Thank you!

(And this is a clear example of the kind of post I want to be able to 'tag and save' in the next version of the software ... working on it.)

NP--deoxit's been very useful for a number of electrical issues I've encountered over the years.