sounds like you've done a great job at going over all the details. the fact that you're able to tell us that the crank and cam sensors are getting signal to the ECU is awesome.

i'm curious about your low 4th piston pressure. if it works like the sky-g you can sometimes get erroneous results due to the variable valve timing. i would retest to be sure but from what you're telling us you do not have symptoms of a compression issue.

as i'm sure you know the injectors are controlled by the ECU based on cam sensor feedback, crank may play a role. not completely familiar with the diesel models. knowing you're getting signal i am assuming you have checked connections at the ECU end. this says to me that unless there is a wiring problem to the injectors the only thing left is the ECU. if i were in your shoes i'd be getting my hands on the wiring schematics and checking every fuse and relay that could play a role in this.

any chance you can swap the ecu with another known working one as you did with your other parts?

 

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

 

Wow, you've swapped out just about everything, and still no joy. Frustrating. I'll start by saying that I've never had the Mazda diesel, though I've had a Ford diesel pickup, so my advice is mostly guessing. So it's worth every penny you paid for it.

Given all the swapping without improvement, seems like the issue is something you haven't swapped yet. Have you checked the grounds, particularly the one from the engine to chassis? Ground issues can cause this kind of crazy-making issue. The engine grounds are prone to falling apart from constant vibration/flexing of the motor. When you say there are no codes, are you looking at pending, or are you also checking for stored codes? Sometimes stored codes won't trigger a CEL, but might point to a cause. How is the battery? A tired battery can cause all kinds of problems. Lastly, how is the fuel? Water or some other contaminates might be detected and keep the injectors from firing (I would expect an error in this case, but you never know).

Normally, at least on the gas motors, if there were a sensor (Cam, crank, neutral safety, etc) keeping the PCM from allowing the car to start, you'd get a CEL and a code. But it's good that you've checked these anyway.

I wonder if there is a way to probe the injector wires at the PCM end to see if you're getting any signal. I would think you'd need an oscilloscope to see the pulses, as they're very short duration, not sure an ordinary multi-meter would see it. I don't have the factory shop manual for the diesel motor or I'd have a look at it. Try downloading it and have a look to see if there's a diagnostic procedure for your situation. The procedure is helpful because it may reveal (by having you check them) the sensors and conditions necessary for the injectors to fire.

The compression on that one cylinder is a bit concerning, as you'll get no bang without enough squeeze. When the engine cranks, does it sound uneven? Three even pulses and one that sounds faster/different is a good indicator of a compression difference. But this should have nothing to do with injectors not firing. Even with one dead cylinder it should start, run like garbage, smoke, and shake like crazy, but it should run.

Lastly, did anything change on the car when the issue started? Get any work done (mechanical or electrical), or install a new gizmo? Have you owned it a long time without issues, or did you buy it recently? How many miles are on it? Just trying to get a sense for the history of the car in case there's a clue.

 

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

 

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.

 

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.

hello, you solved the problem? I have the same problem on a Mazda cx5 2.2 d, I don't know what to change, no results..

 

buna ziua, ati rezolvat problema, aceeasi problema am si eu pe o Mazda cx5 2.2 d, nu stiu ce sa schimb, fara rezultate..

 

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

 

We are a service, we have tried several options, but without result so far. I also spoke to the Mazda representative, they are working on it daily.

 

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

 

I haven't tried that!

 

I'll let you know if I have any news, I'm out of ideas, I've changed a bunch of sensors, injection kit, engine computer, (It stopped, ran out of diesel and doesn't want to start)!

 

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.

 

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?

 

Nothing new, what I had already checked was checked, I tried with the engine computer, I did IMO of and it still won't start..

 

I have the impression that it is something trivial, but I can't figure out what it is, I have 2 injection kits, and another complete engine, I have changed almost all the accessories that would be related to starting, and it doesn't want to start, I am left with no solutions

 

un releu sau o siguranta sau ceva? de la computerul motorului nu este 100%,

 

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

 

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.

 

Timing Chain Learning Procedure, Engine Skyactiv D 2.2 Youtube

 

Tomorrow I'll try this procedure, it's done with the engine off, the ignition on (someone solved it)

 

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

 

I have changed another high pressure pump, and an engine computer,,, no results. I am stuck

 

Am schimbat o alta pompa de inalta presiune, si un calculator motor,,, fara rezultate. sunt blocat

 

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

 

I changed the engine, the old one had filings in the oil, I stopped the car because diesel was flowing from the high-pressure pump, during assembly a gasket was not installed correctly, I stopped it to replace the gasket, after the replacement I bled the system and since then it has not started. And I started changing the same parts as you, I have no signal at the injectors (It is identical to mine, I have read from you since you started) I am waiting for a complete engine with all attachments and I will try with another engine, I don't know what to do anymore...

 

No injector pulse

dont normally ask for help.. but i am stumped.. getting spark, getting fuel to the fuel rail, have reset my ecu.. and i still have no fuel coming out of the injectors.. what am i overlooking?? car ran/drove fine yesterday.. it did this when i tried to start it today..

mazdas247.com

 

I have the impression that someone has solved it but I don't understand it. Tell me if you understand better,

 

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

 

I bought a complete engine today, I'll replace it and we'll see after that..

 

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

 

Start the car!! I just changed the engine to the injection

 

I want to believe that the problem was the injection, it wasn't putting out enough pressure.