Hello,
My super charger only wants to work about half the time. It engages and then the next petal down it wont?
I'm not sure what can cause it to work and then not?
Sure makes it hard to diagnose .
2001 XKR S.C.

Thanks

 

How are you determining that the supercharger is not working....lack of acceleration?

 

If you IC pump is not working you might be getting heat soak and losing performance. I'd ensure it's operating properly.

 

Good Morning,


I notice a difference in acceleration. When its working properly or I assume it literally lifts the front end and can feel the rush.
Now, When its not working or I think its not. It still accelerates up but nowhere comparable. ( I can hear the sing of the SC)


I recently put in a new MAS, Air & Fuel filters. Plus they replaced the S.C. induction gasket with new bolts.
This was done at the Jag dealership. They also It seamed t be fine for a short period of time.


Now, Its just odd the it wants engage in periodically ?

 

Does it always seem to work the first time you accelerate hard, and then not subsequently? That could point to a heat soak issue, possibly due to a problem with the charge cooler pump.

Even with a functioning pump, heat soak can be an issue with repeated hard acceleration, reducing supercharger performance, especially in very warm weather.

With the ignition fully on and engine off, you should be able to put your hand on the pump and feel the vibration of it running.

 

if the pump is out it WILL set restricted performance warning and speed limited engine. It isnt Mad Max, so its on all the time. just in bypass mode when vacuum is pressent, which if truely feel that differant I would look a the bypass solenioid to make sure its not obstructed open or binding. This will give you low boost. If its closed when should be open,it overheats the air and sc. not a good issue either

 

I can hear the pump on my 2002 XKR. I don't hear it on My 2002 XJR but it is noticeably quicker than the XKR. It's probably time to put one of those pumps in stock.

 

On the 2002 and earlier XKRs, a secondary fuel pump failure can also cause power loss.

See https://www.jaguarforums.com/forum/x...el-pump-85882/

 

I was reffering to the intercooler pump btw

 

The condition you are describing sounds like a sticky bypass valve to me. If I remember correctly it is vacuum operated not electric.

 

yes and lack of vacuum opens=full throttle no vacuum=boost
high/er vacuum idle/cruise equals open=noboost goes around sc and not through it

 

If you tee in a vacuum/pressure gauge on the vacuum line and bring it inside the car or fasten it to the windshield you can quickly see if this is the problem while driving. At max throttle you should have about 11-12 PSI boost (positive pressure).

 

Most of the vacuum lines come off the elbow below the throttle body and they will not be in boost because they are on the low side of the SC. They should go to 0 PSI with full throttle.

I think you would need to tap into vacuum at the intercooler to see boost.

 

A good point is between the charge coolers and fuel pressure regulator. I have a full time boost gauge here on my car. See attachment page 6.