Hi, own a Jaguar S type 3ltr 2005 build, 2006 compliance. 134k

Going nuts over LTFT and STFT as OBD2 reader was purchased as Jaguar /Rover specific and full compliance on most after 2005.
Trouble is OBD2 reads in % and at this time showing bank 1 @119% Long Term and short term @124% bank 2 @ 121% Long term and 128% @short which means what?
Now I understand the concept + fuel - fuel, either side of 0 or GMH either side of -128 + also percentage with 0 being spot on 14.7/1 BUT what F are mine telling me??
Yes I know the threads here are many however plenty of speculation but no answer to my question {which I'm now putting to you} but what the f is mine telling me?
IT could be the reader however it's new it could be a new way of expressing trims I don't know. I do know that there is an air leak in bank 2 or left and the fault always sets in a trailing throttle when you would expect more vacuum to be present suggesting I am right .

I have replaced all upper O rings inlet etc checked all lines for cracks etc even the canister is ok. MAF ok throttle body good .
About to change all plugs to NGK platinum all coils to NTK two new O2 Lambda ie upstream. in the hope, it's not a slight miss on trailing throttle etc. And because I will know where everything stands.

HELP!

 

Welcome to the forums Pete,

I've copied this question from your Intro thread for advice from members with the same model.

Graham

 

What reader are you using ?

I use an iCarSoft i930 & I discovered there is more than one way to 'read' the fuel trims. One way gets results like yours & the other shows in % from 0, e.g. showing bank 1 STFT as 2.4% or 5.3%, etc.

 

Hi thanks for the contact,
I purchased a Nexdiag not expensive $200, however, even on boot up, it states com error?
what with com error and strange readings that do not equate its frustrating, to say the least, along with this reader not even finding the right Lambda 1 O2 sensor you have to wonder if it works properly!
Pete

 

Doesn't sound promising. Good luck.

 

Seems a weird tool.

You'd hope/expect there would be a manual/guide!!

Perhaps you are expected to subtract 100.

 

Hey, thanks, guys I am trying to return the useless thing and purchase something known and reliable so I would appreciate your recommendations.
Cheers Peter.

 

Just adjust how you are reading the trim values. They are always presented as a percentage, your just accustomed to reading it as a difference instead of a factor. 100 would be a factor of 1 being applied to the standard trim tables, essentially no adjustment taking place. 120 would indicate enrich the default table 20 percent. 90 would theoretically be a negative 10 percent trim.

For your leak, we all know there could be many causes. Because you appear lean on both banks, I would pay more attention to the common portions of the intake system. A smoke test would be the most revealing. You mentioned renewing several seals. When I solved my leak that seemed quite similar, it was the o-ring and retainer clip that fastened on the underneath of intake right near the throttle body.

I've posted previously on the o-ring replacement as well as building a simple smoke tester. Search my posts if you're interested.

Good luck.