Hi, new to the forum but not mechanics, a friend of mine asked me to look at his 2015 CX5 2.2 (I believe it is) diesel after a crank no start issue, would need to rescan to pull codes again but from memory (it was before christmas) there was codes for low fuel pressure, on checking the pressure at the rail on live data it was building about 4 bar of pressure, I initially wanted to check the low pressure out put but we have had issues finding a low pressure pump and no priming bulb, there is definitely no electrical pump in the tank (we have physically checked), the fuel pipes run to a metal unit bolted to the top of the engine (both feed and return) before running to the high pressure pump with one electrical connector (which looks more like a sensor). I usually work on french stuff and have never seen a setup like this before, I was always told that a high pressure pump requires a primer bulb or lift pump to prime it and everything else I have worked on till now this has been the case, was hoping someone more adept with Mazda's diesels maybe able to shed some light on this please? I did scan over previous threads but could not see anything that stood out as the same issue, any help would be greatly appreciated, I have uploaded a picture of the unit in question below.

 

Welcome to the forum

 

Looking at your photo, almost dead centre is black rubber cap with a spring clamp around it, this is where you attach a vacuum bleeder to, to bleed the fuel after replacing the fuel filter.

 

I thought that maybe the case, my friend was selling the car through his daughters boyfriend who claimed the car had cut out, him and his dad apparently had the high pressure pipes off to visually check the fuel pressure (told me all I need to know about there mechanical skill from that statement) and condemned the pump, I haven't ruled out the HP pump buy since they had messed with pipes I said to my friend we ideally need to establish from live data what pressure is being produced at the rail once the system is bled, he has agreed to a new filter as i suspect this may well be the cause of fuel related running issues as they have had the car 2 years and have no idea when the fuel filter was last changed but it was really making me question how the system is purged of air with no primer bulb or LP fuel pump, makes sense now although I bet there is many annoyed Mazda owners who if they let their fuel run out have to have some one out with a vacuum pump to get the car going again. thank you for the reply, had it been french I would probably have had it running long before now but this one caught me out, I have been doing mechanics for about 25 years, have 3 diploma's but I am always prepared to learn something new, the industry changes things far two often.