A week ago, I went out and cranked the car and immediately it revved to at least 4 thousand RPM's and threw error codes. I turned it off and sat for a minute and cranked it again with no issues. Went to the car show and talked with others who suggested buying a battery tender to keep battery at full charge. I did so and it has been on tender for a about a week now. This morning I start the car and same thing, starts right away but revs to 4 thousand RPM's. I turn it off, try again, same thing. Sit for a few minutes and try again, same thing. Now I am afraid to start car and cannot even think about driving to the shop to have checked.

ANY solutions or things to check?

 

Others might have better ideas, but I would start with a visual inspection of the throttle body for any gunk or buildup around the throttle plate, clean it up if so, and if that doesn't help I would attempt to get an absolute TPS reading (throttle position) from an OBD2 scanner & look for a fairly low angle. If it's reading too high, it could be mechanically stuck open somehow. I would also try MAF sensor cleaner as well. Two inexpensive checks if you haven't already done so, at least that's where I'd start.

 

What codes did the car throw?

 

It revs so hard and sounds so rough I am afraid to let it run long enough to see the codes. I mean, as soon as it cranks, it goes violently to a high rev and I shut it off. In past times I have seen the Traction Control and the Limp Home Mode.

 

Shouldn't your reader find the codes with key-on, engine off? You should also be able to get a TPS angle reading key-on, engine off

EDIT: Also, if you're paranoid about it, maybe pull the fuel pump relay so it won't run even with an accidental crank

 

Upon the advice of club member, went out and turned the key twice looking for codes. No codes found BUT had a very loud ticking noise this time. Did not turn far enough to crank on purpose.
Car typically starts on two turns of starter.

 

I'm surprised it's not rev-limited in park (to 3000).

Er, could it be 3000-ish? If so and it is trying to go higher then the usual rev limiter (as per my car) makes the engine sound bad.

Supposing that's it, in effect it thinks you are revving. Check throttle pedal isn't caught on something / other issue fooling it (which could maybe be a bad MAF or an air leak but I think it would be pre-MAF, and so on).

With a cold engine at start the PCM has few sensors it can trust and also richens the mixture.

 

Get yourself some MAF cleaner and give it a good spray. You will be surprised at the difference it will make.

 

Update from yesterday tests and code reads:
I purchased a OBD II reader yesterday. and we checked codes. First, we removed the air intake plastics to check if butterfly was free and clean. It was clean and there was nothing mechanically wrong with its function or any of the cables from gas pedal. The scanner only pulled up a P1000 code, nothing else. Since it was still revving high headed toward 4,000 RPM (and ran like a drag strip car at the starting post, popping and snapping horribly) before I would shut it off, I decided to do a hard reset of the battery. Removed both cables and held them together as suggested for 30 seconds. Everything and I mean everything reset. After putting all items back together, we did a test crank and it cranked right away with no apparent issues. Today, we took it for a long "drive cycle" to reset computer items. All went well.

A new thing that I notice is that both door windows go down a small amount now when opening. I don't think that used to happen but maybe it should have been??

Note: before this started happening, for about a week, I started using a 4 amp Tender/Charger hooked up in engine bay on positive bolt by the fuse box and negative on shock bolt as suggested in many forums. Maybe I just need to replace battery even though this is keeping it fully charged?

Thanks to the many forum members who offered advice and repair suggestions. It was a scary day yesterday.

 

the windows need to be reset after the hard reset. Hold the window down button down until you hear a faint click after it reaches the bottom of its travel. Repeat for the window up button. After it makes the faint click you are done . Repeat for both windows.

NOTE: proper operation is when the windows go down 10mm approximately when the door is opened, and go back up 10mm when the door is closed.

Z

 

Thank you, that worked perfect. Any other hard reset issues to be aware of? Everything else seemed fine on our first drive afterwards.

 

after the battery is hooked back up:


- Start the car


- Let it idle for about 10 Minutes


It is normal after disconnecting the battery that your RPMs will be high when restarting your car and your acceleration will be very brisk. This is part of the ECM learning process and on your next start up it should be at normal levels. This is like doing a full restart and your car will be forced to learn again - you can also temporarily remove stored problem codes this way.

 

Glad you got this resolved.

Just for what it's worth, there's a whole discussion on this in various threads, but the most economical unit I found which is actually Jag/Land Rover specific is the iCarSoft i930 unit. At roughly $100, I have found value in being able to pull module specific codes. The common scanners will only pull common P-codes, but with this sort of vehicle, there can be many hidden ones you won't see otherwise such as transmission codes and whatnot. (I also bought a Volvo-specific one for similar reasons, to pull ABS codes on my 2000 S70)

 

Lots of codes cannot flag until P1000 turns into P1111 so look out for that.

Checking fuel trims would be wise.