I'm about to do the oil cooler manifold/mount 0-ring replacement (connection to block) on my turbo, so I took the recommendation to clean the area first. Okay, so I violated the rule not to use a power washer, but I didn't think there was anything electrical in the area I hit that could cause what appeared to be a spark/ignition problem.

Afterward, the idle was surging wildly, maybe 800 down to 3-400, and finally it died out. Repeated again 10 minutes later. Then I took it for a drive, with it hardly accelerating, and dying each time I had to stop and idle. After about 2 minutes, it kicked in and never missed a beat after that. I was surprised. I thought it'd gradually improve while drying out, but it was as if someone threw a switch.


I pulled up a picture of a B230FT Turbo (740/940) engine and tried to figure where my spray might have gone. (Does anyone know of a better picture posted anywhere)? I thought that no water could have possibly gone above the level of the block, and couldn't for the life of me think of anything along the lower side of the engine that could cause an electrical problem.

Well now that I've taken a closer look, I have a few ideas.

First, I wasn't thinking about the O2 sensor. On my 240, it's much higher, in the manifold, I now see that it very likely could have gotten hit either while I was spraying up from underneath the rad or spraying back from above the rad. I'm still surprised though that the sensor and/or it's wiring would be so sensitive to water. I don't think it took a direct hit of water, but may have gotten splatter or mist.

It's also possible that when I was spraying from below the rad, water may have gotten up onto the ignition wires or the crank position sensor or its cable. Mind you, the CPS cable has the white ring, which I believe is the newer replacement type. I know water didn't get out near the fender inside the engine bay. I'll have to individually test the O2 sensor & cable / ignition wires / CPS & cable with a misting bottle to see if one is causing this problem.

Anyone have any opinions on any of these suspects, or any other potential cause? I'm assuming that regardless of what it is, a new unit should withstand water, shouldn't it? I don't think it was a matter of water blasting into anything. The instantaneous disappearance of the symptom however still puzzles me.

--
David Armstrong - '86 240(350k km?), '93 940T(270k km), '89 240(parts source for others) near Toronto