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peterpete190
peterpete190, Auto Technician
Category: Mazda
Satisfied Customers: 29140
Experience:  Auto repair Technician with 17 years experience.Past ASE and other certifications.
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Mazda CX7: I am an auto tech I have been in the industry

Customer Question

Hi I am an auto tech I have been in the industry for about 8 years I have recently run into an issue that baffles me on a 2007 Mazda CX7 I have hooked up my fuel pressure gauge on the low side of the system and when I start the vehicle it primes at around 58psi and once I start the vehicle it goes crazy there is no real way to describe what its doing. It started with a trouble code P2187 and I have been doing pressure testing to figure this out. Hoping you are able to help Is there a way I can email you a video
Submitted: 1 year ago.
Category: Mazda
Customer: replied 1 year ago.
Heres the video for my fuel pressure gauge https://www.dropbox.com/s/0melma9wbliwshy/My%20Movie1.wmv?dl=0
Expert:  peterpete190 replied 1 year ago.
Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay. Your fuel line pressure should be between 60 and 71 psi and hold steady and may climb when revved up.The pressure test is actually done in a special procedure type way here.This looks to be an issue with the pump itself as the pressure regulator will cause this and this is built into the fuel pump assembly.I would do the pressure testing following the correct procedure below to see if the pressure is in line with what it should be.If it is not the pump most likely needs replaced and is most common for this issue and code here.1. Complete the "BEFORE REPAIR PROCEDURE".You can skip this2. Disconnect the vacuum hose from the intake manifold that connecting to the power brake unit. 3. Disconnect the negative battery cable. CAUTION: The quick release connector may be damaged if the tab is turned too far. Do not turn the tab over the stopper. 4. Disconnect the quick release connector from the fuel tank. 5. Push the SST quick release connector into the fuel pipe and plastic fuel hose into the SST until a click is heard.https://www.dropbox.com/s/6u7ss2fcfp5p0dz/fp-04-28.gif?dl=06. Turn the lever parallel to the hose of the SST as shown. 7. Connect the vacuum hose to the intake manifold that connecting to the brake booster. 8. Connect the negative battery cable. 9. Start the engine and let it idle. Measure the fuel line pressure. - If not as specified, inspect the following: Zero or low - FP circuit - FP - Fuel line (clogged) - Fuel leakage inside pressure regulator High - Pressure regulator for high pressure cause Fuel line pressure 410 - 490 kPa (4.2 - 4.9 kgf/sq.cm, 60 - 71 psi) If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete
Customer: replied 1 year ago.
I did follow these instructions as I found them on all data I had one guy tell me it could be a the high pressure pump back feeding into the low pressure system but my gut is telling me it is the low pressure pump in the tank because the regulator is in there
Expert:  peterpete190 replied 1 year ago.
This does look to be the regulator as the cause as I have seen before and is common and it is built into the low pressure pump system.I suspect the same as you on this here with what is occuring that the pressure regulator is the cause and the low pressure pump needs replaced.I have seen several regulators fail in the past before with issues like this here with it needing replaced. Let me know if you need anything else and feel free to rate my help here. Thanks Pete