As soon as I fired it up after the wash I got the dreaded yellow light and restricted performance. P0327 and P0332 knock sensor signal low on bank 1 & 2. I did a little reading and it seems this happens to some people after driving in a heavy rain, tho they didn't state their fault code numbers, then it goes away the next day; I am really hoping for that. I the meantime I checked what I think are the connectors and they're dry. Are they the ones at the front of the heads on a metal bracket on the valve cover screw? If not please point the way so I can check them. Got the engine warmed up and a fan blowing down on it hoping to speed any drying that needs to happen.

I had much reservation about washing it but decided it 'shouldn't' hurt anything....

 

Plenty of stories in the archives about how engines are NOT designed to be washed. Wiped down with a rag, yes. I cringe every time I go past a car wash and see some fool with hood open blasting away........

 

I've washed plenty and only had one minor issue on a 928, but of course the Jag would be one to dislike water.

 

Keep the car dry and not running for a day or two. That'd be the first thing I'd do before looking further into it.

 

Cured! Left it sit with the hood up and a big fan blowing for a couple hours and it stopped showing that code....but thenI got a P1699 Can Bus failure...****ETY FUC...wait a minute. I reinstalled the RCCM, all good now. I took a little drive to get it hot and leaving the hood open to ensure there's no moisture left somewhere. I swear this car is really testing my anxiety threshold. But then driving it, ooohh yea that's nice.

 

+1 never NEVER Powerwash under the bonnet / hood area, you're just asking, in fact begging for trouble as you've found out.
To be honest, if you've got away with this on other cars, its probably more by good luck than good judegment.


Happy to hear she's dried out and all A ok again

 

I've probably washed at least 50 engines, most with a high pressure powerwasher. This one I went easy and just used a mild fan spray from a hose. Considering that even just driving in the rain can cause this knock sensor issue it's obviously a design issue, but at least it's self-curing. I won't disagree that washing an engine can cause problems, but considering that many dealerships and carwashes do it regularly as well as many owners I wouldn't say it's all that hazardous.

 

Expect every modern car to be similar. I frequent other sites and see this sort of report quite often.

 

I had my S Type for a week when I drove too fast through a puddle producing immediate limp mode and misfires on 4 cylinders.. I ended up changing all the coils and plugs.

 

Just change the knock sensors. They're not expensive. One possibility is that they may be chafed and only act up when wet. New sensors probably will rectify that situation as they did in my case.

 

That's easy to say when you don't have to pull a supercharger to get at them. I've now read many more reports of water triggering those faults and them self-curing when they dry. Either the sensors are very delicate or the computer very sensitive, but it appears to not be indicative of faulty sensors and just something that happens if they get wet. Apparently drivability isn't effected below 3K RPM so some just keep driving till the problem clears.

 

Given that the probability of experiencing problem from pressure washing is relatively high, and that it's not the most effective or efficient way of cleaning an engine, I fail to understand why anyone would argue in it's favour.

 

I've read:
it looks better
I've always done it

Followed by: now it doesn't run right (or at all)...

 

^+1. My favorite one was the guy in a the car wash bay next to me. I took a look - and he flooded his fusebox, that sat behind the wheel well. Some vehicles, like my '98 F-150 had leak problems (just from RAIN) that would take out the most important electronics module - so why tempt fate and open the bonnet to apply water?

 

You are right! They are not easy to get to on a STR. Good thing is they don't seem to fail much if at all.

https://www.jaguarforums.com/forum/a...1&d=1445613834
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Does this really happen? How deep of a puddle are we talking about

 

It was about 5" deep. I was going about 35mph.

 

I replaced a 4.0 AJ28 engine about a dozen years ago when I worked at the Jag dealer.
A customer drove through a large puddle and ingested water into the intake.
The air filter was soaking wet and the engine was 'hydrolocked'.

A connecting rod was sticking through the side of the engine block.
Insurance company paid for a new engine AND the core charge since Jaguar did NOT want it back as a rebuildable core.

I also used to have to get engines started after they were powerwashed by someone and towed to the Jag dealer. Warranty does NOT cover drying harness connectors and replacing damaged components.

Powerwashing a 1970 Small Block Chevy engine is one thing but a modern engine is a whole 'nuther' beast!!!!!!!!!!!

bob gauff

 

Most likely the coils were fine and it would have cleared up after drying.

 

As above guys, I'm afraid all we can do is offer advice from our many years of wisdom, either that or we were once silly enough to do this very thing....lol
However, we got the knowledge and pass it on as best as we can.

If, the person / owner we are trying to help / advise etc, knows better and insists on continuing in this vein, what can you do???