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Hello
Some background to my problem
I have two Mazda 3 diesels One is a 2015 (engine built by me) and the other a 2014 model both have just over 100k miles
The 2014 will not start. I aquired it as a non runner with a suppossed fuel issue. The owner said it had been running It had obviously been assessed with no success
Using Forscan to diagnose the issue I found that their was no codes but there was very low fuel pressure so changed the filter, checked the fuel lines using vacuum
Still not good so replaced the HP pump (cam driven on the diesel) and the fuel rail with its sensors and the suction control valve.
Fuel pressure now on cranking is equal to the desired and similiar to the 2015 engine when it's cranking
That completed I decoked the manifold (they get full of carbon) and replaced the camshaft and vacuum pump Both worn and pump had low vacuum
Whilst I had the rocker box off I checked the chain/tension and removed the crankshaft pulley to confirm that the chain was where it should be
By removing the crankshaft pully you can see the spot on the sprocket is aligned wth the gold link in the chain and at the top of the engine the marks align..all good
The engine will not start and by checking with a test light I find no injector pulse (checked the 2015 car and it has one)
Before going further I completed the following checks
Accessed the turbo vanes to see that they were free and not loose
Checked that the DPF wasn't blocked and cleaned through the intercooler
Removed the following items and tested them in the 2015 car to confirm if they work which they do
Crankshaft sensor, camshaft sensor, map and maf sensors, exhaust pressure sensor and all the injectors...
Tested the engine wiring loom for breaks
I also did a compression test and no1 cylinder is only 170psi however all the others are 280psi
The key seems to be accepted by the car as when the clutch is depressed to start the green key appears in the dash and the button light turns green
Now I'm getting out of my confort zone so got a Haynes manual electical trouble shooter, watched several scannerdanner videos and tested various elements of the wiring with a multimeter. I have to say that I have had the odd reading that didn't match the trouble shooter but when I took a comparable reading on the 2015 running car It was the same result.
Thinking the ECU/PCM could be faulty I sent it to be tested however I was told by this particular company that they could not even clone it
Whilst I was mulling over my next move I did check the engine number and it has definitly had a replacement engine but basically the same unit as the original I wonder if the pcm was transferred along with the engine?
That apart I aquired an "engine start kit" from a similiar model, It consists of PCM, Speedo, SSU, front and rear BCM's the key and its transponder unit, TCM, ABS and several
other modules that are checked by the PCM before starting. Fitted these...cleared any connection codes and cranked the engine. Result no codes no communication errors and no injector pulse
At this point I'm a wondering if there is a failsafe or if there is any other area I should examine more closely
I'd also like to thank in advance anyone who's waded through this and has any thoughts
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