Car runs rough after engine wash.

[KantGo55]

I just bought my daughter a 1993 Nissan 240SX and found an oil leak at the front of the engine under the valve cover area. I changed the oil and washed the engine to locate the exact location of the leak. I covered all electrical areas including the fuel injector connections before washing the engine.Following the engine wash I removed the foil I used to cover everything and blew the excess water with a air hose. Now the engine runs terrible.I don't see how water could have gotten into the distributor but I can't think of what else may cause this?I let the engine idle a while and thought maybe the heat would dry any water that was trapped in a connection but that didn't help either.Any ideas?BTW: the car has 138000 miles on it.Thanks.
Modified by KantGo55 at 7:17 PM 4/16/2007

[KantGo55]

I starting think about the spark plug boots, I went and unplugged each one and I could see what looked like a little moisture in a couple of them. I iwll leave them unplugged overnight with a warm engine and maybe they will dry out.

[audtatious]

Yeah, let it dry out. I would suggest popping off the distributor cap and letting that dry out too.

[KantGo55]

OK, everything should be dry now and problem still exist.I changed the oil from 10W30 to 5W30, would that matter?

[rogoman]

OK, everything should be dry now and problem still exist.I changed the oil from 10W30 to 5W30, would that matter?

Your change in oil has no effect.

The ignition wires may be cracked so there may be trapped moisture. Also remove the distributor cap and check for moisture.

Make sure there's no moisture on the fuel injector harness connectors.

Check the harness connector for the crank angle sensor that's on the distributor.

[KantGo55]

I did a diagnostics check on the ecm and it showed a code of 34 which indicates a knock sensor.Would a knock sensor create hesitation problems?

Also, what is the best way to reset the ecm?

[CKillSX]

a missfire will sometimes throw a knock code. a miss will cause heasation as well. check for spark by puting a long screwdriver in the spark plug boot and then grounding the screwdriver. look for the current to arc from the screwdriver to the block. repeat for all cylinders. if you have spark then it is prob water in the injector harness.

Dan

[98koukile]

Disconnect the battery for 2 mins I believe that will reset your ECU

[KantGo55]

I decided to change spark plugs, wire set, rotor and distributor cap.When I removed the spark plugs there was water in the threads of the 3 and 4 plugs that had seeped through.I had removed the boots earlier but didn't see any water, I guess because it seeped through.Sparks plugs were rusty and the rotor and distributor cap had corrosion on them.Car runs great now, i am glad it wasn't the knock sensor.Thanks for the replies.