XJS Resonator Removal

XJS Resonator Removal

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Discussion

Jimbeaux

Original Poster:

33,791 posts

232 months

Wednesday 23rd May 2007
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Will removing the resonators (mini mufflers) from my 1995 XJS help any with idle and fuel mileage. I read frequently that they clog up. However, someone said that they later model XJSs did not. Opinions?



Also, is the exhaust note without these loud or just a more throaty growl?

Trooper2

6,676 posts

232 months

Thursday 24th May 2007
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Jim, resonators are there to deal with any noise that makes it past the mufflers and are usually a straight through design, either glass pack type or Helmholtz type. because they basically work like a glass pack I would find it hard to believe that they could plug and increase back pressure, causing your idle and fuel mileage problems. Removing them will probably increase the exhaust noise some what, but I think they are often used to tune the exhaust note by the manufacturers, so your exhaust may or may not sound good if removed.

The cats are more likely to be the part of your exhaust system that would cause the problems which you describe. They would plug more readily than any other part of the system.

Have you thought about replacing the spark plugs (make sure you get the exact ones that Jaguar specifies) and maybe taking it in for a professional fuel injector cleaning? Both of which could also be common causes of your slight misfire (idle) and poor fuel mileage.

Edited by Trooper2 on Thursday 24th May 21:14

Jimbeaux

Original Poster:

33,791 posts

232 months

Thursday 24th May 2007
quotequote all
Trooper2 said:
Jim, resonators are there to deal with any noise that makes it past the mufflers and are usually a straight through design, either glass pack type or Helmholtz type. because they basically work like a glass pack I would find it hard to believe that they could plug and increase back pressure, causing your idle and fuel mileage problems. Removing them will probably increase the exhaust noise some what, but I think they are often used to tune the exhaust note by the manufacturers, so your exhaust may or may not sound good if removed.

The cats are more likely to be the part of your exhaust system that would cause the problems which you describe. They would plug more readily than any other part of the system.

Have you thought about replacing the spark plugs (make sure you get the exact ones that Jaguar specifies) and maybe taking it in for a professional fuel injector cleaning? Both of which could also be common causes of your slight misfire (idle) and poor fuel mileage.

Edited by Trooper2 on Thursday 24th May 21:14
Hey derric; yes, I have changed plugs, fuel filter, and shop-cleaned the injectors & trottle body. Rough idle is much better since I diconnected the battery and reset the "computer"....seems to have adjusted. I also cleaned the MAF with contact cleaner. The random roughness I seem to still experienece at times is likely either a coil going bad, or an exhaust leak I missed. The cats are not plugged yet according to the exhaust shop.

Trooper2

6,676 posts

232 months

Thursday 24th May 2007
quotequote all
You might also check for a vacuum leak which could also cause a rough idle and fuel mileage concerns.

Jimbeaux

Original Poster:

33,791 posts

232 months

Friday 25th May 2007
quotequote all
Trooper2 said:
You might also check for a vacuum leak which could also cause a rough idle and fuel mileage concerns.
Yea, I need to do a down & dirty crawl through the works checking all hoses, etc.