[ttleader]

Hi and thanks for reading and replying
Yes ....and I have gone further by substituting a complete "starter kit" comprising PCM, Front and rear BCM's TCM, SSU, DC/DC module, Instrument Cluster, starter button, transponder and matching key, and the three modules mounted to the internal fuse box, from a similiar model. Once installed all the communication codes were cleared. The immobiliser lights go green, the fob locks and unlocks the car and everything works as it should but still no injector pulse.
For good measure I have changed the front harness and the engine power harness ..still no joy
Diesels are bad for carbon build up so decoked the inlet manifold. Checked the inlet shutter valve.
Checked the chain is correctly aligned, changed the exhaust cam (they wear badly) and the vacuum pump. Finally checked the turbo vanes are free and no excess play in the shafts.
The diesels aren't that much different to the petrol engines but don't have VVT and the fuel pump on the mazda 3 doesn't have an electric priming pump unlike the diesel CX5 with the same engine and that does have an electric priming pump.
Unfortunately I still haven't resolved this so if you have any further advice it would be most welcome

 

[ttleader]

Hi and thanks for your insites ... This is a real tester!
The 2.2 sky-activ is probably the closest diesel engine to a gas engine with a (low for a diesel) compression ratio. It even drives more like a gas engine compared to the MZR diesel
Grounds were an early port of call as I believe the PCM grounds the injector voltage to create a spike or pulse. Its a good idea to check pending codes and something I'd not thought of doing.
Battery is good and I did clean the starter motor internals which improved the cranking speed.
I did invest in a powerprobe with a scope which is excellent at checking signals (cam crank injector etc) so have tested signals at the PCM. Prior to that I had rebuilt the fuel system, even checking in the tank incase of water ingress. Diesels are very fussy about fuel pressure and as the Mazda 3 diesels don't have an electric pump to assist the mechanical pump they can be a nightmare to pressurise.
I'm concerened about the slightly low compression but until it runs it's difficult to assess.
Do you know if there is a link between no compression and no injector pulse?
Your last point is a good one. I haven't seen this run as it was a non runner. The owner said that it just seem to run out of fuel...hence the complete overhaul of the fuel delivery system. I can only take him at his word and work through the problem.
I have had no feedback from the main dealer so had a chat with a very nice man at a garage who gave me a number for an auto electrician he uses. He may have come across a similiar issue before.
It will be a couple of weeks before that happens but I will post any developments.
Thanks again

 

[ttleader]

By way of an update. I had a tech take a look and he disconnected the cam sensor and took an rpm reading with a scantool from the pcm. The pcm is not receiving an rpm signal from the crankshaft sensor. The previous measurements taken with the cam sensor connected must pick up the rpm giving a false impression that all was well. Rooky mistake!
So checked the wiring and changed the sensor. Still have no rpm signal and no injector pulse.
I've looked to see if the reluctor wheel is in tact and all appears well...even checked the sensor end to reluctor wheel gap.

 

[ttleader]

After replacing the crankshaft sensor, testing the 5v ref circuit, ensuring power and ground to the other two wires from the PCM. I still did not have an RPM signal a the PCM
I have now found a company who say they can look at the PCM so am awaiting their comments
But in short no...its not yet fixed

 

[ttleader]

Have you tried the test to determine if you have an RPM signal at the PCM?
Make sure you disconnect the cam sensor otherwise your scantool will read the RPM from the cam The PCM needs an RPM signal from the crank to start. I will post how I get on

 

[ttleader]

Sounds like we have the same problem. I did get a starter kit with all the modules, instrument cluster, transponder etc but that gave the same result, no injector pulse. I'm just hoping that the company I sent the PCM to has found a problem because ...like you, I am out of ideas and haven't really found the not so local dealer to be helpful.

 

[ttleader]

Update on PCM test. The company have been unable to determine if the PCM is good or not. They are the second company that have assessed it and not been able to diagnose it. This is a real problem as I now cannot be sure what to try next. bonciumarius54 Have you had any luck with the Mazda representative?

 

[ttleader]

What was the result from the RPM test?..Knowing the result of this may help to narrow it down.
I had to move the car uphill into my garage. To do this I wired passed the clutch pedal down switch. Removed the clutch pedal up switch and wired passed the neutral switch to facilitate moving the car in gear using the the starter motor. When I put it back together (it was hooked up to the scope) it fired and produced 1 injector pulse. This is as near as I've got to making it run

 

[ttleader]

Just got your post on the timing correction. How do I do this if the car wont start? Can it be done without starting and cannot open the jpeg despite regestering.

 

[ttleader]

Ok... this sound promising as the car acts as if it's immobilised ...but there's no immobiliser problem.
Just waiting for the returm of the PCM and I'll give it a try at the weekend, let me know how you get on Thank you

 

[ttleader]

I've changed the HPP with the same results. Here is a list of what else I've changed....if you could look at the list and tell me what you've done maybe we can eliminate things already covered
I changed the fuel filter, replaced the High pressure pump and the suction control valve. The fuel rail with the pressure sensor and pressure relief valve. also checked the tank. Changed the cam and vacuum pump. Injectors refurbished, cam, crank, maf and map sensors all work in another car. Emissions harnes replaced and then the front harness including the fusebox in the engine bay.
As I said I tried a starter kit inc PCM, front and rear BCM's DC/DC, unit StopStart unit. Instrument cluster, Starter button, Transponder and key, and the three modules which attach to the fuse box inside the car foot well.
Beyond that I have removed the inlet manifold and cleaned off the carbon. Tested the throttle body, checked the turbo spins freely, checked the exhaust pressure sensor feed isnt blocked, Swopped the neutral switch sensor on the gearbox. Cleaned out the EGR and bypass and changed the starter motor.

The lack of an injector pulse is caused by my PCM not seeing the crankshaft signals, however I'm still not convinced that the PCM isn't just stopping the pulse because something else isn't right.
The reason I still don't think its the PCM is that I've already tried another one and get the same result, and, I had just one injector pulse after moving the car
Does your PCM see the crankshaft signal?
So if you have completed some other tests if you could list them it will help

 

[ttleader]

I'm sure someone has solved this as I don't think we are the only ones to have this problem
Unfortunately I'm struggling too and it's a problem for many garages as they too have no idea.
Do you use Forscan as it has an osilliscope function which I have used to map the fuel pressure
I keep coming back to the PCM not seeing enough fuel pressure, it then ignors the crankshaft signal and so doesn't fire the injectors....but I haven't been able to prove that. my next efforts are going to be around the signal sent from the pressure switch on the fuel rail and compare those to a running car

 

[ttleader]

I will be very interested to hear how it goes. Will you be changing the pcm and associated modules or will you just change the engine and keep the electrics of the original vehicle?
I have my PCM back but when I switched on the ignition the headlamps came on (when not switched on) so apear to have further issues ....I'll keep you informed

 

[ttleader]

Thats Great!!!... When you say you just changed the engine to the injection.... what part are you calling the engine? and does the part you actually changed have a part number?.. Finally does your scantool actually tell you the pressure in your injection system? This infomation would really hep me

 

[ttleader]

Thank you ...I understand now. That's not an option for me as a another engine would cost the same as the car ...so not worth it. Pleased you got yours sorted.
I will review the fuel pressure info and check that the PCM is receiving the required info...it may well be the reason that the PCM won't let the injectors fire by stopping the crankshaft RPM signal from being recognised

 

[ttleader]

Thank you ...I understand now. That's not an option for me as a another engine would cost the same as the car ...so not worth it. Pleased you got yours sorted.
I will review the fuel pressure info and check that the PCM is receiving the required info...it may well be the reason that the PCM won't let the injectors fire by stopping the crankshaft RPM signal from being recognised

By way of an update: I was focused on not having an injector pulse and having disconnected the Camshaft sensor I had no RPM signal from the Crankshaft sensor at the scan tool...so the engine would never run. (leaving the camshaft sensor connected gives a false rpm signal)
I decided to wire the crankshaft sensor connector to the crankshaft sensor on a Mazda 3 that runs. Cranking the running car sent an rpm signal to the scan tool connected to the non running car leaving only two possible causes for no rpm signal. 1 faulty crankshaft sensor (replaced twice) or 2 faulty reluctor ring.
I removed the sump to find that the reluctor ring was damaged in such a way that only a partial signal was sent and thus no complete rpm signal. I also found that the no1 con rod was bent in an S shape and had contacted the reluctor ring causing the damage
Remedy: Bend the reluctor ring back to a circle and replace the piston and con rod
The car now runs and has equal compression on all cylinders
Recap
I was told it just stopped
Initally had no fuel pressure...filter, pump, fuel rail and SCV changed.
Checked all sensor and wiring ...all ok
Complete starter kit tried with no change
Cleaned out the inlet manifold and EGR valves
Realised that there was no Injector signal
Cause: Reluctor wheel damaged along with No1 conrod
Engine not original
Once started the intercooler to throttle body pipe came off as it was short by 40mm
The turbo actuator arm fell off as there was no retaining clip causing the exhaust pressure sensor to blow apart.
It's very possible that the engine was replaced with a unit that had been hydro locked as I've only ever seen an S shaped conrod that has failed for that fault
Nine months to get to the bottom of this One week to fix it!