Fuel Pressure Relief Valve

[Mad_Trbo]

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

 

[Mad_Trbo]

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

 

[XLRATING]

Try this link (hopefully it works): https://www.xlr-net.com/forums/cadi...digital-service-manual.html?highlight=Chilton

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.

 

[xlrlist01]

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.

 

[dennis93coupe]

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.

 

[dennis93coupe]

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.

 

[Mad_Trbo]

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.

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.

 

[dennis93coupe]

Mad_Trbo, did you get my PM?

Top LH side look for the black plastic cap.

 

[Mad_Trbo]

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.

Mad_Trbo, did you get my PM?

Top LH side look for the black plastic cap.

 

[rodre]

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.

 

[rodre]

Bump, someone must have a repair manual?

 

[xlrlist01]

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

 

[ccclarke]

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