Cadillac XLR Net - The ultimate online hub for Cadillac XLR owners and enthusiasts!
Supporting Membership - Supporting Vendors / Dealers - Advertise With Us

Thanks Thanks:  0
Likes Likes:  0
Dislikes Dislikes:  0
Results 1 to 13 of 13
  1. #1
    Junior Member Mad_Trbo's Avatar
    Join Date
    Aug 2015
    Location
    Dallas
    Posts
    24
    Post Thanks / Like

    Cadillac XLR

    XLR/V

    Default Fuel Pressure Relief Valve

    New to this platform, where is the fuel pressure relief valve, I've looked along the rail and can't seem to locate the schrader valve I am accustomed to seeing.

    I would like to check fuel pressure.

    The reason I am getting a lean mis fire at idle and according to the dealer ship PID p0171 & p0174.

    Thanks in advance

  2. #2
    Junior Member Mad_Trbo's Avatar
    Join Date
    Aug 2015
    Location
    Dallas
    Posts
    24
    Post Thanks / Like

    Cadillac XLR

    XLR/V

    Default Service Manuals

    Short of putting out in excess of $400 can someone point me to a link for service manuals. I want to review fuel pressure as mentioned earlier along with all vacuum lines.

    Perhaps there is a CD ROM that contains everything. I've recently purchased a Tech 2 with a tough book to diagnose the V but I need to be able to reference components and would prefer not to search instead review documentation.

    Again any help with the fuel pressure relief valve is appreciated. An image is most useful - thank you

  3. #3
    Fuel Pressure Relief Valve XLRATING's Avatar
    Join Date
    Jul 2011
    Location
    Virginia
    Posts
    1,493
    Post Thanks / Like

    Cadillac XLR

    2006 Infrared XLR (Beauty); 2008 GT500 (Beast); 2007 Black XLR-V (Victor)

    Default

    Try this link (hopefully it works): Digital Service Manual

    If the link doesn't work, search "Chilton" on here, one result is "Digital Service Manual." Some folks have used an online subscription service for things like you're looking for.

    Hope that helps.

    yep, I drive a hybrid - a V8 bred for high speed!

    2006 Infrared XLR
    Corsa exhaust
    XLR-V sway bar
    Powder coated calipers
    Drilled & slotted rotors
    Custom engine cover
    Custom hood & trunk liner
    Zaino polish

  4. #4
    Pit Crew
    Join Date
    Oct 2013
    Location
    HSV
    Posts
    173
    Post Thanks / Like

    Default

    Quote Originally Posted by Mad_Trbo View Post
    New to this platform, where is the fuel pressure relief valve, I've looked along the rail and can't seem to locate the schrader valve I am accustomed to seeing.

    I would like to check fuel pressure.

    The reason I am getting a lean mis fire at idle and according to the dealer ship PID p0171 & p0174.

    Thanks in advance
    As you have identified, P0171 and P0174 are lean conditions, both bank 1 (171) and bank 2 (174).
    You should read the workshop manual before carrying out these procedures, especially how to activate the fuel pump safely and to purge the system.
    The workshop manual diagnostics only include a test of the fuel rail pressure after other checks. If there are other codes, fix those first. To diagnose you need to read the fuel trim readings (Tech-2) (>25% is a fault). Also, make sure you have more than 10% gas in the tank. Step 3 is to check the Heated O2 sensors (Tech-2) (0.96-1.04 good). Then, check vacuum hoses and pcv. It also refers to fuel contamination (with alcohol). After that lot, it gets more difficult, looking for leaking exhaust forward of the HO2S, leaking injector O-rings, throttle body leaks. If fuel trim is over 25% consider a faulty mass air flow sensor, see code P0101 for more information. The workshop manual states that the pressure test point is on the fuel rail, under the fuel injector sight shield (the big cover). The pressure regulator is integral with the pump, there is no return line. Correct pressure is 55-62 psi (2004, std motor). You must purge air from the gage (J34730-1A). Observe all safety procedures for handling gas.
    Last edited by xlrlist01; 04-16-2016 at 11:50 AM.

  5. #5
    Pit Crew
    Join Date
    Mar 2014
    Location
    Orange County, California
    Posts
    157
    Post Thanks / Like

    Cadillac XLR

    2009 XLR-V Crystal Red with Ebony / Cashmere 1 of 6

    Default

    Quote Originally Posted by Mad_Trbo View Post
    Short of putting out in excess of $400 can someone point me to a link for service manuals. I want to review fuel pressure as mentioned earlier along with all vacuum lines.

    Perhaps there is a CD ROM that contains everything. I've recently purchased a Tech 2 with a tough book to diagnose the V but I need to be able to reference components and would prefer not to search instead review documentation.

    Again any help with the fuel pressure relief valve is appreciated. An image is most useful - thank you
    If you want the paper edition you can buy a new set from Helm's. What year is your V? I have a used like new set for a 2006 I need to make dissappear. PM me if you are interested, otherwise I'm going to put them up on ebay soon.

  6. #6
    Pit Crew
    Join Date
    Mar 2014
    Location
    Orange County, California
    Posts
    157
    Post Thanks / Like

    Cadillac XLR

    2009 XLR-V Crystal Red with Ebony / Cashmere 1 of 6

    Default

    Quote Originally Posted by Mad_Trbo View Post
    Short of putting out in excess of $400 can someone point me to a link for service manuals. I want to review fuel pressure as mentioned earlier along with all vacuum lines.



    Perhaps there is a CD ROM that contains everything. I've recently purchased a Tech 2 with a tough book to diagnose the V but I need to be able to reference components and would prefer not to search instead review documentation.



    Again any help with the fuel pressure relief valve is appreciated. An image is most useful - thank you

    If you want the paper edition you can buy a new set from Helm's. What year is your V? I have a used like new set for a 2006 I need to make dissappear. PM me if you are interested, otherwise I'm going to put them up on ebay soon.

  7. #7
    Junior Member Mad_Trbo's Avatar
    Join Date
    Aug 2015
    Location
    Dallas
    Posts
    24
    Post Thanks / Like

    Cadillac XLR

    XLR/V

    Default Proper Procedure

    Thank you for the notes, I have a tech 2 on the way and I am working on some manuals which I need badly in order to understand how to diagnose this car.

    I had an unfavorable experience at the dealership, they wanted $600 to do some menial work. I think the modifications to the body annoyed them.


    Quote Originally Posted by xlrlist01 View Post
    As you have identified, P0171 and P0174 are lean conditions, both bank 1 (171) and bank 2 (174).
    You should read the workshop manual before carrying out these procedures, especially how to activate the fuel pump safely and to purge the system.
    The workshop manual diagnostics only include a test of the fuel rail pressure after other checks. If there are other codes, fix those first. To diagnose you need to read the fuel trim readings (Tech-2) (>25% is a fault). Also, make sure you have more than 10% gas in the tank. Step 3 is to check the Heated O2 sensors (Tech-2) (0.96-1.04 good). Then, check vacuum hoses and pcv. It also refers to fuel contamination (with alcohol). After that lot, it gets more difficult, looking for leaking exhaust forward of the HO2S, leaking injector O-rings, throttle body leaks. If fuel trim is over 25% consider a faulty mass air flow sensor, see code P0101 for more information. The workshop manual states that the pressure test point is on the fuel rail, under the fuel injector sight shield (the big cover). The pressure regulator is integral with the pump, there is no return line. Correct pressure is 55-62 psi (2004, std motor). You must purge air from the gage (J34730-1A). Observe all safety procedures for handling gas.
    2006 Augmented XLR-V, Dubbed Z06 Package. Looking for ways to increase output with current platform.

  8. #8
    Pit Crew
    Join Date
    Mar 2014
    Location
    Orange County, California
    Posts
    157
    Post Thanks / Like

    Cadillac XLR

    2009 XLR-V Crystal Red with Ebony / Cashmere 1 of 6

    Default

    Mad_Trbo, did you get my PM?

    Top LH side look for the black plastic cap.

    Last edited by dennis93coupe; 04-16-2016 at 09:03 PM.

  9. #9
    Junior Member Mad_Trbo's Avatar
    Join Date
    Aug 2015
    Location
    Dallas
    Posts
    24
    Post Thanks / Like

    Cadillac XLR

    XLR/V

    Default This is what I am talking about! *** Fuel Pressure Relief Valve!****

    Thank you, this is very helpful, I don't understand how I overlooked this. I'll take another look this afternoon.


    Quote Originally Posted by dennis93coupe View Post
    Mad_Trbo, did you get my PM?

    Top LH side look for the black plastic cap.

    2006 Augmented XLR-V, Dubbed Z06 Package. Looking for ways to increase output with current platform.

  10. #10
    Junior Member
    Join Date
    Apr 2017
    Location
    Vancouver
    Posts
    2
    Post Thanks / Like

    Cadillac XLR

    2008 XLR-V

    Default

    Quote Originally Posted by xlrlist01 View Post
    As you have identified, P0171 and P0174 are lean conditions, both bank 1 (171) and bank 2 (174).
    You should read the workshop manual before carrying out these procedures, especially how to activate the fuel pump safely and to purge the system.
    The workshop manual diagnostics only include a test of the fuel rail pressure after other checks. If there are other codes, fix those first. To diagnose you need to read the fuel trim readings (Tech-2) (>25% is a fault). Also, make sure you have more than 10% gas in the tank. Step 3 is to check the Heated O2 sensors (Tech-2) (0.96-1.04 good). Then, check vacuum hoses and pcv. It also refers to fuel contamination (with alcohol). After that lot, it gets more difficult, looking for leaking exhaust forward of the HO2S, leaking injector O-rings, throttle body leaks. If fuel trim is over 25% consider a faulty mass air flow sensor, see code P0101 for more information. The workshop manual states that the pressure test point is on the fuel rail, under the fuel injector sight shield (the big cover). The pressure regulator is integral with the pump, there is no return line. Correct pressure is 55-62 psi (2004, std motor). You must purge air from the gage (J34730-1A). Observe all safety procedures for handling gas.
    Hello,

    I have ended up with old gas in my 2008 xlr-v and would like to drain the tanks. You mention about "activating the fuel pump to safely purge the system", can someone explain to me how this is done? Also, where is the fuel filter for this? I am guessing that will need to be changed as well? I put ethanol free 94 octane in this but it is almost a year old. Thanks.

  11. #11
    Junior Member
    Join Date
    Apr 2017
    Location
    Vancouver
    Posts
    2
    Post Thanks / Like

    Cadillac XLR

    2008 XLR-V

    Default

    Bump, someone must have a repair manual?

  12. #12
    Pit Crew
    Join Date
    Oct 2013
    Location
    HSV
    Posts
    173
    Post Thanks / Like

    Default

    Quote Originally Posted by rodre View Post
    Hello,

    I have ended up with old gas in my 2008 xlr-v and would like to drain the tanks. You mention about "activating the fuel pump to safely purge the system", can someone explain to me how this is done? Also, where is the fuel filter for this? I am guessing that will need to be changed as well? I put ethanol free 94 octane in this but it is almost a year old. Thanks.
    The filter is inside the gas tank

  13. #13
    Pit Crew
    Join Date
    Sep 2008
    Location
    Uncanny Valley, New England
    Posts
    967
    Post Thanks / Like

    Cadillac XLR

    2013 Graphite Metallic XTS Platinum

    Default

    Quote Originally Posted by rodre View Post
    Bump, someone must have a repair manual?

    Many procedures reference other preliminary procedures, making a write-up very time-consuming, plus you don't get the necessary illustrations for key component locations. This is the advantage to having your own set of service manuals if you're equipped with the skill set and requisite tools to perform service yourself. Yes, factory service manual are expensive, but they can pay for themselves when compared to the price of a single repair.

    In the meantime, you can download what you need from the factory Service manual here for a minimal daily fee: RepairProcedures.com - Providing electronic service information for 1995 to current GM vehicles

    Much cheaper than the entire set. I often cut and paste useful info into Word docs for later use.

    CC
    Last edited by ccclarke; 05-29-2017 at 05:55 PM.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Cadillac, XLR and XLR-V are registered trademark of the General Motors Corporation & Cadillac Motor Division.  Neither Cadillac Motor Division nor any subsidiaries of GM© shall bear any responsibility for XLR-Net.com content, comments, or advertising. XLR-Net.com is independent from GM© and is not affiliated with, sponsored or supported by GM©.  Copyright/trademark/sales mark infringements are not intended, or implied.  All Rights Reserved