I've had my '04 XJ8 for two years now, since it had 76,xxx and today it rolled over the 91,xxx mark and I have not had any major issues with it... Until last week.

I took my car for its customary 3k oil change and car wash only after it came out of the wash the engine was off and even though it went in on. Tried to crank it and it just turned over and did not fire.

Waited 15 minutes figured something got wet that shouldnt have and same result. Getting antsy I started going over the fuses under the hood and I found that F20 or F30 (depeding on which diagram I follow), a 10A fuse was blown.

After replacing it the car started right up but with a restricted performance message and a check engine light.

The message went away after a few minutes and the car drove fine for about 200 miles.

Then, while on a 100 mile drive I got agitated at a slow traveling car in the left lane an attempted to pass him by lead footing it and as i roared by him, suddenly the car gave a big shudder and a blinking CEL came on and the restricted performance message came on.

I pulled into the right lane and coasted at about 60mph and the message went away 2 minutes later and the performance returned to normal.

Today I pulled the code from the CEL and it came up as follows:

I cleared the codes and watched the frame data from my ODB reader and all the voltages for the O2 sensors were within normal range and the car has been fine for the last 50 miles since.

One thing I should mention that the second restricted message came as the car hit the rev limiter and did not shift gears immediatly, I think the "bump whine" issue was not fully resolved. I did the software update for the trans but I did not add fluid.

I am not sure how that factors in to this issue, but figured I should mention it.

Any insight would be greatly appreciated!

 

Uncanny. Found this while seeking info on a low-speed misfire and engine fault symbol that has persisted after an almost identical sequence of events, fill-up, car wash, total shut-down while overtaking (had to coast to a stop, wait a minute, re-start).

Didn't have my reader with me, paid an indy dealer to read me the raw codes. then grokked 'em off the Shop Manual .pdf's I *did* carry-with on my laptop.

Neither roughness, nor detectable loss in fuel economy at road speeds, so felt OK making the trip home would not worsen the issue(s), did so - been driving other of my wheels, not the 2005 XJ8-L.

Codes and all showed near-as-dammit the whole same story, save only ONE cylinder (#3) reporting a misfire, which has persisted, but only below 1200 RPM, and which I am now researching.

More as I dig out my notes and go through the actual sorting of it all....

 

A tech I know at my local dealer saw an almost identical issue. Check your weatherstripping below the windshield. Turned out the guys sprinklers would come on at night and freak things out by seeping into the connections and coil, but would eventually go away with driving. And stay away from car washes....those things are horrible. Whether they're the soft touch brush crap or the high pressure sprays, both have serious drawbacks.

 

had a similar issue with my 04 XJ8 after car washes. blown fuse twice and then the dreaded Restricted Performance. End result was to replace four coil packs, which did show up on my code reader. No problems since, but also no car washes!! Just by hand. Used aftermarket coil packs at $53.00 each

 

wow! This is valuable information. -but whether you wash by hand or not water is water... and thorough washing at home will still use lots of water..

Is this a common problem?

 

Not even sure it is relevant. Have the covers off mine now, and the nature of the very light dust pattern conveys no indication that moisture has EVER gotten into that area. Also no change from application of moisture-clearing spray solvent to the connector area.

One-each of three different brands of direct coil are now en-route, plus a full set of 8 Champion Iridium sparkplugs, so 'more as it transpires'.

 

IMO there's lots of very good valid reasons NOT to use any drive through car wash, swirl marks ruining the paint finish for one, usually they're not that thorough either and don't do the best job.

Its a very easy and quick way of keeping the car generally clean IMO but not for me.

Further - the high water pressures involved or the constant attack from ALL angles that these types of car washes produce cannot be replicated by hand washing and or with a garden hose.

 

Of course there's the choice one takes to either use or not. I've gone thru them before.. and haven't had any swirling issues. Actually it's statistically better to use the carwash because most people don't know how to wash properly and actually cause more swirls/scratches by using dirty water, washing wheels and body from same bucket

but my question was a concern about water leaking into the car to make it go "haywire" vs an auto detailing seminar. lol. is this a common occurrence that water leaks into the base of windshield or a very rare issue

 

I've owned or nurtured a goodly number of motorcars since forever-ago, about half bought new, and IMNSHO, my 2005 XJ8-L is the 'tightest' / least-affected by car-wash intrusion of any of 'em. Even two that had, respectively, 30" and 60" 'fording' capability with all the seals, snorkels, and elevated differential vents that rating entails.

Sure - it has an above-average number of drains and diversion 'systems' that need to be kept clean, not clogged, but ....harbouring Oak trees, as I do, which in turn host tree-rats, I keep after the leaves, stems, acorn stashes, etc, and - so far - no issues.

In an odder situation - clearing a blockage of my windscreen washer plumbing, I had applied enough compressed air back through the system to blast 80% of the contents of a topped-up washer-fluid reservoir up, out, and all over the adjacent area. That, too, drained away w/o detrimental effects.

Water may get IN, but unless ... seals, drains, and general neatness have been neglected so as to trap/retain it, it also gets right back OUT quickly, and with no enduring adverse effects.