Took my 1999 XJR up to O'Charley's to pick up some late to-go dinner last night. Very casual drive. Got home, pulled into my garage and hit the throttle twice before I shut it down. But to my dismay, it wouldn't rev over 3000 rpm! Like a rev limiter, but way below redlline. I tried gradually increasing pressure on the pedal, then just flat flooring it. No more than 3K! No messages on the dash, not "limp mode" or "engine failsafe" indications on the dash. Just no more. It was late Saturday night so I thought better of testing it on the road. But I shut it down for about an hour, tried again. Same thing. Any ideas what I'm dealing with? Anybody?

Submitted by jpbii@yahoo.com on Mon, 10/17/2011 - 11:09

Steven, sorry I misunderstood your comment.
Art, Actually, when you rev the engine prior to shutting it off it increases the oil pressure ever so slightly thereby effectively adding lubrication to the cylinder walls. The fuel is burned off during the revving. The increased oil pressure briefly remains. Honestly, I just made that up. But it almost sounds believable! I didn't turn it off immediately after revving to 3,000 rpm. But I fear we are splitting hairs now. This is not a habit of mine. That's why I was so surprised and concerned at the resulting rev limit. Nuf said? I think. And thanks for all replies.

Submitted by silver007@shaw.ca on Mon, 10/17/2011 - 09:40

revving an engine and turning it off right away is a bad thing..... the unburned gasoline will tend to wash the oil off the cylinder walls..... let the engine idle for a minute if you can before you turn it off........if you have run it hard just prior to shutdown try and let the engine idle for two or three minutes..... if possible raise the bonnet to help cool down and stop heat baking all the plastic in the engine bay...........
Go fast and make it Last....

Submitted by jpbii@yahoo.com on Mon, 10/17/2011 - 00:50

Gentlemen,
Starting with William, why not hit the throttle lightly before leaving your baby all alone in the garage for the night. I just love the sound of that engine. I wasn't winding it up! Just a couple soft touches of the pedal to hear it purr before I shut it off. I've never done that before. Perhaps that's why I was surprised that at 3 grand it limited. Took it out for a drive tonight. Puurfect. Smooth power as always. No limiting at 3 grande.
Doug, you must be right. As I said, I've never tried it before, but in park rev stopped at 3,000 rpm. On the road, kinda depends on which side of the J-gate you're on.
I am surpised a bit by the two of you being so curious about why a person might rev their engine slightly before turning the car off. I wasn't seeking the red or yellow line! The engine idles around 1K. Cruises a little over 2 or 3K. Redlines just over 6K. I wasn't nailing it. When I noticed it didn't want to rev over 3K in park with a mild pat on the pedal I tried a little harder and mashed the pedal. Still, 3K rpm tops. This is a good thing I just discovered. I had a formal girlfriend jump in my car in the dead of winter, fire it up and she raced the engine until it threw a rod. The Jag won't do that. :-}
Steven, Thanks for your word about the "fly by wire" system. My 99 XJR seems to be equipped with that.
I'm still surprised about all of your curiousity about reving the car in my garage. William and Doug, tried it twice because it wouldn't rev beyond 3,000 the first time. Steven, floarboarded out of curiousity. I was trying to see if it would rev over 3,000. I was worried and thought I had a problem.
Come on, none of you guys ever revved your car before pulling the key out ot the ignition? How about after you first start it? THAT's a bad thing to do!

Thanks for your replies guys,
Jay

Submitted by stevejag@sbcgl… on Sun, 10/16/2011 - 12:27

The later fully "fly by wire" systems do have a 3000 RPM limit when in neutral; not so with the cabled throttle bodies. Try a full throttle acceleration on the road in a lower gear and see if you can exceed 3000.

I want to know about the garage floorboard thing, too!

Cheers,

Submitted by dougdwyer1@com… on Sun, 10/16/2011 - 09:11

Lots of cars have limiters to prevent free-revving in neutral or "P". I suspect Jaguar does as well. I remember them on some cars back in the 80s, even.

I'm curious about the "hit the throttle twice" thing as well

Cheers
DD