tisk tisk, 2 pages of posts and only 1 partially touched on first thing to diag. fuel pressure. this symptom is a common thing when fuel pump 2 goes bad in any sc jag. its comes on for boost/rpm above 3k. recieves a signal from the ecu to the rear electronic control module to relay 15 out to both fuses f-47, and f-49 both 15amps to the fuel pump 2 control module in the trunk then to the pump through pins 7, and 8 on the fuel tank cap under the passenger side rear seat. check the fuses and if bad replace both pumps. they go bad from too many amps when going bad(ie you can replace the fuse only to have it happen again). replace both cause youre going in there and theyre the same age. when the primary goes out youll be on the side of the road. if both fuses are good swap relays around to ck for bad relay. after those quicky checks run a fuel pressure test while driving. yes youll need a fuel pressure gauge and long line taped to the windshield or you can monitor through the message display in engineering mode. the reason it varies on falling on its face is because the primary pump can cover the added needs up to a point. the random misfires are from the engine leaning out so you get restricted performance and ck engine light cause it can cause engine damage if you continue. they go away with the problem but can probobly be seen depending on "trips to trigger". They can be found with a good scanner or jag ids or sdd under pending codes. forget the air box code not realtive to anything for this issue. Ive seen people block it open and take out without issue. to properly diag a car you cannot get bogged down with the chaff, you need to only look at the wheat and this is why I laugh when customers say"the car gives you codes and tells you whats wrong with it!" uhhhh yeah right, it gives you "clues" and you have to be the detective and know what clues are important and which ones up front are not important and ellimanate suspects, just like a cop

 

Brutal, Excellent diagnosis.

 

That's some great info Brutal. I knew the car was leaning out... I didn't realize the 2nd pump isn't constantly active in an STR, but rather only kicks in when it's needed. That's what threw me off a bit....

Take care,

George

 

Hey! hey! Wasn't it me who came back asking the poster that he could be looking at a fuel issue? On the other hand, the poster mentioned in his opening post that he suspected the fuel pumps were at fault. Regardless, Brutal came in and kicked all our asses.... He's such a "brute".

 

Superchargers do fail! The one on my car was replaced prior to me buying it. And the prior owner WAS a member here. I sent him a message but was ignored. Here's his thread.

https://www.jaguarforums.com/forum/s...ad.php?t=20806

 

sc's rarely fail, what you experiance is they "KNOCK" at idle. and Im not talking about a little, all knock alittle, its just the clearance noise of the rotors against each other at idle under no load. Just like a driveshaft and diff when you rotate the driveskaft back and forth by hand. You feel and hear the clearnace taken up between the drive and coast side of gears, axles etc.....
Its when the knocking becomes very loud at idle. The from drive coupling inside wears on contributes to most of the change. All SC knock some, you really need to know whats normal and whats not. for instance, Ive replace 1 sc for noise in 14 years, and seen only a few replaced in the shop otherwise.

 

Im going to set up an appointment early next week so we can try out some of these ideas, Thanks everyone for the input and i will keep you updated!

 

Quite a few suggested fuelling but without Brutal's knowledge more data needed.

The local shop clearly were useless

 

I want to know what the local shop would have done after he charged the OP 4k+ to swap the SC and then fired the car up and it still ran the same way.....

I'm sure he would have gotten to the fuel pump eventually but I wonder if he would have tried to pass the buck on the S/C.

Oh and jagv8 - you need to get a copy of scanmaster-elm if you have an ELM 327. I can provide you with a copy off forum if needed. It does real time 02 monitoring with calculated mixture

Take care,

George

 

You missed my posts about having AutoEnginuity? Does far more.

 

Will that work with the ELM327 interface or does it require its own?

George

 

well guys, Unfortunately after pressuring this local shop to hunt around and try some other diagnostics, I am also convinced its the S/C. There is way too much noise comming out of that thing to be normal. they have found me a used one with 38K miles off a totaled STR. I also confirmed with the shop owner that if my car runs the same after they install a new S/C its not coming back on me. Im poking around town in a rental nissan versa and cannot find anything positive about driving this crap trap. Hoopefully i will be back up and running on im my STR tuesday. I will let you all know!

 

well guys, Unfortunately after pressuring this local shop to hunt around and try some other diagnostics, I am also convinced its the S/C. There is way too much noise comming out of that thing to be normal. they have found me a used one with 38K miles off a totaled STR. I also confirmed with the shop owner that if my car runs the same after they install a new S/C its not coming back on me. Im poking around town in a rental nissan versa and cannot find anything positive about driving this crap trap. Hoopefully i will be back up and running on im my STR tuesday. I will let you all know!!

 

Have them replace the coolant hose under the SUPER CHARGER as the only way to replace is to pull the SC again

 

Just noticed this. Sorry for the delay. It uses its own hardware, included when you buy. I hope they've fixed the design flaw (wrong grounding).

 

YES!! +100 on that. You only want the work done once and the hose costs almost nothing.

 

Hi All
For reference and anyone reading the original posts its the Cats
Had EXACTLY the same symptoms for months. Eventually in desperation changed the cats and all was well in the world