In an effort to aid in the infamous P0171 and P0174 codes that lead to a lean running condition, I have color coded all vacuum lines.

I believe that the following pictures will go from MY (Model Year) 2003 on up. There seems to be some confusion with 1 vacuum elbow located under the lower intake manifold. I believe this elbow is on MY 2002 and older, this ais a known failure. Heres a link to replace them: http://jagrepair.com/VacuumLeakSType2000.htm <--THANK YOU GUS!! There is also a rubber elbow located at the back of the upper intake as well taht is a common failure as well for the MYs 1999~2002

To check for vacuum leaks use either carb cleaner or water in a misting bottle. Remove the plastic engine cover to access all lines. Run vehicle and liberally spray down vacuum lines one at a time, if the engine revs up or down, time for futher inspection.

Included as well are MAF Sensor location and IMT O-Rings. The above is the first place to start in hunting down the P0171 and P0174 codes.

This link will aid in diagnosing if the IMT O-Rings are bad: https://www.jaguarforums.com/forum/s...ck-pics-49214/


**PLEASE NOTE** I am not a computer guru nor a tech, if you cannot read the text, save pictures and enlarge.







In above picture, the Fuel Pressure Regulator Vacuum Line is just a short 90 degree elbow. No visable picture able to be taken.

 

Brilliant! Mods please FAQ!!

 

OK, it's worth FAQ , thanks for the write up

 

Awesome job.........I wish you had a 4.2 This would be much ned right now!

 

Rick,

Very well done as always. Hope the mods add this to the FAQ section soon, and that I will be able to remember that it is there for when I may need it....

 

Nice job Rick, a picture always helps.

Caddie has already added the link to the FAQ's

 

Awesome Rick!

Didn't realize you went ahead and did this already. Sorry I havent gotten a chance to call you back yet. If you're in the man cave, give me a buzz!

Take care,

George

 

Dam Rick you out did yourself this time! Kudos to you!

 

thanks alot Rick.!! iver been dealing with both those codes for over a week now, and since i dont have a scanner that reads live data, its been really difficult for me to diagnose the problem.. this will be great help in me checking for vacume leaks on my own..

your engine bay seems a little different than that of my STR.. do you think that would mean any significant difference in how the vacume lines are setup?? i hope not.!! Thanks again.!

 

Since the attachments are our 3.0 liter and myself never laying eyes on an STR, 4.2 or 4.0 under the hood anyways, I don't know.

Sorry I can't be of more help.

Now if the V8 guys want to send me a couple of engine pics, I may be able to figure something out.

 

Rick

I would really appreciate the V-8 version of the vacuum tube routing, in particular the supercharged version for my 2004 XJR

thanks in advance I have both P0174 and P0171 codes

RyeJag

 

In the mean time see if this helps http://www.jagrepair.com/images/Auto...otos/P0171.pdf

 

Once again, beautiful job of documenting a difficult DIY project, Rick. Thanks for taking the time to teach us how to do this stuff.
Steve

 

Gus

thanks for the guide, I will be digging out the old vacuum gauge an putting it to work. What is the MAS sensor and its location?

thanks

RyeJag

 

Thank you for the details answer. I have sent to my friend mechanic for further action. Due to back and neck problems, my wrenching days are over. Unless its a much larger hood.
thanks again

 

I'm hijacking this old thread to ask about the green line (Camshaft vent tube to intake tube).
My 3.0 V6 has been running very poorly when cold (especially when idling), but runs fine as soon as it's warm (above 60 degrees).
My OBD scanner only tells me "mixture too lean" and "misfires one or multiple cylinders".
I suspect a vacuum leak and have noticed the mentioned tube sits very loose in the Air Intake Hose.
It doesn't click in place, I can only push it in.
Is there supposed to be a seal around it? If so, what should it look like?
Thank you!

 

A better or even cheap elm327 should at least give codes (Pxxxx etc) which you can look up in the OBD PDF for your car on JagRepair.com - Jaguar Repair Information Resource

It also helps to read live data and look at fuel trims (do read some existing threads!) as they'll show if there's an sir/vac leak.