98 xjr.no engine lights.stock besides cone k&n filter and exhaust has cats into x-pipe and only stock rear mufflers. motor has 140k.cant power brake it or punch burn even with s button pushed down. is this normal or is something wrong?

 

Sport mode on (red led lit),
push the trac off button
and let'r rip!
You can't power brake these cars, but you can burn some rubber from a stop with the above mentioned.

Another possibility is that there's something wrong with your car. Secondary fuel pump is dead, dirty MAF sensor, etc, etc... Does it run strong when you get on it hard??

I reread your post. The S button will actually be in the up position to be on. It's reverse psychology if you ask me. Maybe the little red led is burned out??

 

sport mode is on (little red button lit).when the engines cold ill get posi till it hits second and can punch burn but when it reaches normal temp (gauge in the middle) is when it wont do anything but yea itll get right up to 90 in no time.i have a bad abs sensor so the track and stability failure and the amber light is lit.the lighs dont come on all the time.

 

If it is loosing power when warm, check the intercooler pump.

The intercoolers ( where it say supercharged ) should not be boiling hot after a drive.

 

when the intercooler pumps fail you get restricted performance, cause well, the intercooler and intake air becomes too hot and causes detonation which will damage a engine. Hense restricted perf.

 

the intercoolers do get hot.almost to hot to touch but I get no performance restrictions.the pump on the drivers side works.is there another pump I need to check?

 

There is a pump on the pass side between radiator and engine that pumps the intercooler's coolant loop, that would be the first thing to check. I think it should be running anytime the car is on, so you can turn key on without starting and feel the pump to see if it's on.

 

just got back from a ride and intercoolers were to hot to touch.turned the key on and also started it and pump wasn't running.
anyone know the part number for the bosch pump

 

0392022010 is the upgraded model. Will need to go to mercedes for the push pin (??) is what I think they call it. It's roughly under $10 for the "push pin". No I don't know that number. You'll have to do a search on this forum.

 

Forget Power Braking.
Dude, This is a jag, remember?
If your posting on this forum, that means your car is over 15 years old.
Power braking and old jaguars are a bad combination unless you've modified the whole power train.

With the TRAC control off, I can light up the tires as long as I want from a standing start.

Power braking will only destroy the transmission sooner.

 

+1 with what Rpach10115 said, ....I can leave a lite 11 with posi on, but it won't be spinning, it'll be clawing with traction. With it off, I can smoke the RR, ...literally have rolling smoke coming up. I've only done that twice, that was enough.

 

I power brake my car frequently, before and after LSD install. Usually to warm tires when i'm at the strip, sometimes when I have a passenger/spectator looking for thrills or lots of smoke.

With that being said, you should be able to drop the hammer anytime with no brakes applied and do a nice long "one tire fire" burnout with ease. So yes, something is lacking. I still can do a decent burnout from a standstill with no power braking and both of my rear tires gripping. The ultimate reason I installed LSD was to stop all of the wheel spin from starts.

Another short disclaimer.....I beat the hell out of my cars and wouldn't advise others to treat their cars as I do unless you feel like keeping up with the maintenance bills/repairs

 

my intercooler pump wasnt working.I took the cover off it and cleaned all the black soot out of it and got it working but intercoolers still get hot and I think thats the reason.the ait tells the computer if its hot and retards ignition right?

 

Have you looked over/drained/flushed the cooling system at all? it's possible, especially if all that coolant has been sitting for a while without being circulated, that something's gummed up in the intercoolers or radiator. There's a procedure for filling and bleeding the intercoolers, I don't remember the order of operations but it involves opening up that 19mm plug on the "v8 plate" and filling through there, then cycling the car on/off so the blower IC pump runs and circulates coolant the IC loop.

Black soot in the IC pump doesn't sound promising either.

I don't remember the exact thermodynamics with heat-soak and performance, I think it's got to do with the reduced efficiency of the supercharger when compressing hot air as opposed to cold air.

 

+1, I've never power braked the jag (feels abusive to do that, lol), but before replacing my rear tires, while on private land I've experimented with plain flooring it off the line with trac-off, and even my n/a vdp (non s/c) can spin the wheels leaving a trail of smoke from both rear wheels (despite no positraction)

 

I installed a used motor and am flushing the system now with prestone flush and straight water