I washed my engine yesterday for the 1st time. I didn't wash it any different than I did a couple of other 5.3's. 1st thing I noticed were crazy boost presssure readings on my Attitude monitor (28.5lbs of boost at 5mph...I don't think so). 2nd was a strange exhaust tone. The 3rd thing...I sprayed WD40 on some of the connectors and this led to the CEL coming on. I'm going to O'Reilly's at lunch to get the codes read. Any suggestions or thoughts about what's going on?

check thread "cleaning your engine and engine bay"post #15

You should never use WD40 on electrical connections. WD40 is a penetrating oil not a electrical contact cleaner. I would get some contact cleaner and spray all the connections down that you did with WD40 and make sure that they are dry when you put them back together. Second when you wash the engine bay do not hit the electrical connections with the high pressure spray. It forces the water into the connections and that is the root of your probs I would say. Those connections are designed to be water proof under low pressure not high pressure water.

I used the WD40 because it is a water dispersent, just like you would use it to dry out a distriutor cap. I'm going to try CRC and an air hose next.

None the less. WD40 is a oil. Is displaces the water with oil. You can get away with that in distributer cap cause that is running high power through it and the connections that the edge are connected to are low power and the oil changes the conductivity of the wires and can mess things up (I work with low power electronics at work and WD40 is a no no).

Gotcha! I picked up the alcohol based CRC electrical cleaner during lunch. What you're saying makes sense because I noticed there were still wet spots in the Edge connectors. I wiped them down and sprayed the CRC. I wiped them down again and left them hanging where they would drip dry and I left the hood up to help air everything out.

Next time, just spray some Greased Lightning Orange Blast on the engine and spray off without any rubbing or high pressure - it just requires normal hose pressure from your garden hose - and it'll take the gunk right off. I did that the other day and had nary a single problem.

Careful because some electrical cleaners will melt the plastic.Some will destroy a circuit board.Try it on a piece of plastic first..

Seems to be acting better today, but I'm still gonna check for condensation in the connectors. I'll try the orange stuff next time.

Good to hear!!!!!

Use Caig DeOxit - nothing comes close! Seal with Caig Pro Gold.

Good Luck!

also Ive seen the CRC contact cleaner made for plastic, melt,deface some plastic pieces,like over spray off itm so far no damange to the plugs