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sprinkles08
sprinkles08, ASE Certified Technician
Category: Australia Car
Satisfied Customers: 22986
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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Mzda bt50 2008 wont start after replacing crank angle sensor

Customer Question

Mzda bt50 2008 wont start after replacing crank angle sensor and resetting codes . No new codes come up.
JA: Tell me a bit more about what's going on so he can help you best.
Customer: Car had been missing randomly then became hard to start and stopped and would not restart. Scan tool showed crank anle sensor fault code and some others. Ckp seemed to be the problem as tacho also stopped. Replaced crank angle sensor and reset codes. Motor turns over fine can see tacho pulsing while winding engine but it will not start. There is fuel but injectors dont seem to be firing. No cdes come up on the scanner unless I disconnect something. It is like the engine immobiliser is on.
JA: Are you hoping to fix this yourself?
Customer: I have a mechanic assisting me
JA: Is there anything else the Mechanic should be aware of about your car?
Customer: Not tnat I can think of.
JA: I'm sending you to a secure page on JustAnswer so you can place the $5 fully refundable deposit now. While you're filling out that form, I'll tell the Mechanic about your situation and connect you two.
Submitted: 1 year ago.
Category: Australia Car
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

It's possible that you could have a wiring or connection issue but there is good chance the crank sensor is still the issue. It may not be producing a usable signal.

Where did the replacement sensor come from?
Do you know what P code had set previously?

Customer: replied 1 year ago.
The sensor is new. these are the codes before'
===PCM DTC P0405-FF===
Code: P0405 - EGR Sensor A Circuit LowModule: Powertrain Control Module===END PCM DTC P0405-FF======PCM DTC P0404-FF===
Code: P0404 - EGR valve position control performance or range faultModule: Powertrain Control ModuleDiagnostic Trouble Code detailsEGR valve position control performance or range faultThis DTC may be caused by :Open CircuitShort circuit to ground or batteryDamaged or worn vacuum hoseEGR valve assemblyBlocked hoses / filter / valvesFaulty or damaged PCM.===END PCM DTC P0404-FF======PCM DTC P0093-FF===
Code: P0093 - Fuel System Leak Detected - Large LeakModule: Powertrain Control Module===END PCM DTC P0093-FF======PCM DTC P0093-FF===
Code: P0093 - Fuel System Leak Detected - Large LeakModule: Powertrain Control Module===END PCM DTC P0093-FF======PCM DTC P0335-FF===
Code: P0335 - CKP sensor circuit malfunctionModule: Powertrain Control Module===END PCM DTC P0335-FF======OBDII DTC P0093-C===
Code: P0093 - Fuel System Leak Detected - Large LeakStatus:
- Confirmed - malfunction is confirmedModule: On Board Diagnostic II===END OBDII DTC P0093-C======OBDII DTC P0335-C===
Code: P0335 - CKP sensor circuit faultStatus:
- Confirmed - malfunction is confirmedModule: On Board Diagnostic II===END OBDII DTC P0335-C======RCM DTC B1342===
Code: B1342 - ECU defectiveModule: Restraint Control ModuleDiagnostic Trouble Code detailsECU internal faultThis code is set when an internal failure detected within the ECUORThis code is also set when theRCM is not configured. Please try to configure the RCM first.Refer to the workshop manual for further diagnosis and repair.===END RCM DTC B1342======RCM DTC B1317===
Code: B1317 - Battery Voltage HighModule: Restraint Control Module===END RCM DTC B1317======RCM DTC B1318===
Code: B1318 - Battery Voltage LowModule: Restraint Control Module===END RCM DTC B1318======RCM DTC B1877===
Code: B1877 - Driver safety belt pretensioner resistance is too highModule: Restraint Control Module===END RCM DTC B1877======RCM DTC B1869===
Code: B1869 - Lamp Air Bag Warning Indicator circuit failureModule: Restraint Control Module===END RCM DTC B1869===replaced crank angle sensor and reset codes.
===PCM DTC None===
Successfull DTC reading, no error codes foundModule: Powertrain Control Module===END PCM DTC None======OBDII DTC None===
Successfull DTC reading, no error codes foundModule: On Board Diagnostic II===END OBDII DTC None======RCM DTC None===
Successfull DTC reading, no error codes foundModule: Restraint Control Module===END RCM DTC None===I have disconnected the crank angle sensor and the PO335 code comes back reconnect and 0 codes again.
Expert:  sprinkles08 replied 1 year ago.

Where did the replacement sensor come from?

Customer: replied 1 year ago.
I bought it from Cape York tyres in Cooktown. Who ordered it from their spare parts supplier in Cairns.
Customer: replied 1 year ago.
Part no. CAS221 on invoice.
Expert:  sprinkles08 replied 1 year ago.

Aftermarket cam and crank sensors are known to cause repeat issues because they often don't create a correct square wave signal.

Are you able to monitor data?

Customer: replied 1 year ago.
I am using Forscan on a laptop. not very experienced with it. but it does monitor various data.
Customer: replied 1 year ago.
I was monitoring the Tacho while cranking and there was a signal showing
Expert:  sprinkles08 replied 1 year ago.

Are you able to see crank sensor RPM? If so is it steady while cranking, and what RPM do you see?

Customer: replied 1 year ago.
I think it was only about 190. not strait line but fairly consistent.
Expert:  sprinkles08 replied 1 year ago.

Is it dropping or increasing although cranking speed stays the same?

Customer: replied 1 year ago.
No it stayed at the same level. I can do some more checks, but the car is 35 kms away and thereis no internet or mobile phone service there.
Expert:  sprinkles08 replied 1 year ago.

It's a diesel, correct?

Did you look at actual rail pressure versus commanded when cranking?

Customer: replied 1 year ago.
it is diesel. No did not look at rail pressure.
Expert:  sprinkles08 replied 1 year ago.

Let's take a look at that next since you had a fuel system ode.

Customer: replied 1 year ago.
I can go check that. Any other checks that may help?
Expert:  sprinkles08 replied 1 year ago.

If you can see the cam sensor or cam/crank sync it would be a good idea to look at that also.

Customer: replied 1 year ago.
The fuel fault codes were when we checked that fuel was coming through the filter ok. We cant hear or feel the fuel injectors firing when cranking.
Expert:  sprinkles08 replied 1 year ago.

The injectors won't turn on if rail pressure is low.

Customer: replied 1 year ago.
fuel pressure is 6370kpa attached screenshot of scan
Expert:  sprinkles08 replied 1 year ago.

What was actual compared to commanded?

Customer: replied 1 year ago.
I would think that the actual pressure is what is displayed on the graph. I do not know how to obtain the commanded.
Expert:  sprinkles08 replied 1 year ago.

It would be shown in the data. The actual pressure you found was very low and is most likely the cause of the no start but we need to compare it to actual.

Customer: replied 1 year ago.
Where do I find it in what data?
Expert:  sprinkles08 replied 1 year ago.

It will be in the engine controller data.

Customer: replied 1 year ago.
Not finding the engine controller data using Forscan. Will borrow another scanner today and check what I can find with it.
Expert:  sprinkles08 replied 1 year ago.

Ok.

Customer: replied 1 year ago.
Using professional scan tool could not find commanded fuel pressure in any of the available data. Also searched through the BT50 workshop manual and can find no reference to what the fuel pressure should be. What is the next step. It seems the injectors are not firing because the fuel pressure is low. What could be causing that and how do we find what the pressure should be?
Expert:  sprinkles08 replied 1 year ago.

Do you have a 2.5 or 3.0?

Customer: replied 1 year ago.
3.0 litre
Customer: replied 1 year ago.
The Mazda service training manual gives idle Rail pressure as 32 mpa. 6000 kpa is probably low. Is it the fuel metering valve or the pump or something else?
Expert:  sprinkles08 replied 1 year ago.

It could be a leaking injector (most likely), the high pressure pump, lack of supply to the pump, and I believe there is a fuel quantity solenoid on the fuel rail which could be leaking.

Did the engine die while driving initially?

Customer: replied 1 year ago.
it became hard to start then stopped like it switched off on the highway.
Customer: replied 1 year ago.
There was a lot of black soot around the exhaust and the back of the car. Which could indicate an injector was leaking.
Expert:  sprinkles08 replied 1 year ago.

The hard start does point to an injector issue. What usually happens in these cases is an injector fails mechanically or multiple injectors are worn. The affected injectors will either bypass fuel through the return system or leak into a cylinder while cranking. This prevents proper rail pressure from building so the injectors won't turn on.