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Mazda MX-5 Engine - No spark, no injectors firing, no crankshaft sensor reading


Icedmunkie

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Hello,

This has probably been done to death but I can't quite find the right answer.

I have a 1.8 MX5 engine in a Vauxhall Firenza. I can get the coil packs (as it's converted to coil on plug) to fire on demand and the injectors to fire on demand but not when cranking the engine. 

The original pickup is now replaced with a 32-2 trigger wheel but nothing registers on the scope.

I've set up the trigger to reflect this but nothing seems to work. Have I overlooked a setting somewhere? I get the feeling it's probably some very simple but not sure what. 

Any advice would be helpful. 

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NA8, NB1 or NB2 1.8 Motor? Does it have VVT?

Is the 32-2 on the crank or cam, if on the crank does it have a cam sync signal?

is the sensor on the 32-2 wheel a 2 wire or 3 wire sensor?

Could you also attach a copy of your tune please

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The Mazda MX5 Trigger Mode suits the NA motors with just the CAS sensor
The Mazda MX5 OBD2 Trigger Mode suits NB1 motors
The Mazda MX5 VVTi Trigger Mode suits the NB2 motors with VVT

I'm not quite sure how to set the cam sync up for you on a G4+ but your Trigger Mode should be 'MultiTooth / Missing' with Trigger 1 Tooth Count set to 36 and Missing Teeth to 2.

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24 minutes ago, Adamw said:

What is the sensor from?  Do you have a part number of something?

I am pretty sure from memory it's one like this, probably bought from the link below. Will have a closer look tomorrow.

https://www.mx5parts.co.uk/crankshaft-position-sensor-aftermarket-mk2-25-p-4362.html

Will update the trigger settings tomorrow and see what happens.

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with the trigger pattern I specified and with trigger 2 set to off it'll only sync in the correct spot half of the times you try and start it. if it's waste spark and group injection this is fine but if it is direct spark it will only run half of the times you try to start it. You will also need to do the typical trigger calibration process to set the offset.

Looking through similar trigger patterns Toyota 1JZ VVTi mode might work as it has the same crank pattern and a similar cam pattern.

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7 minutes ago, Vaughan said:

with the trigger pattern I specified and with trigger 2 set to off it'll only sync in the correct spot half of the times you try and start it. if it's waste spark and group injection this is fine but if it is direct spark it will only run half of the times you try to start it. You will also need to do the typical trigger calibration process to set the offset.

Looking through similar trigger patterns Toyota 1JZ VVTi mode might work as it has the same crank pattern and a similar cam pattern.

I will have a try tomorrow and let you if any of thise suggestions work.

 

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if the crank trigger wheel has been replaced by a 36-2 aftermarket wheel the 99-00 Miata non VVT uses 3 teeth on the cam and is not currently a supported pattern, however you can remove the valve cover and cut off 2 of the 3 teeth on the cam gear fairly easily then you can make it work without any issues. 

@AdamwThis is the trigger setup I'm gonna get you the scope for, tons and tons of the existing miata's have already swapped out the OEM 4 tooth crank wheel for the 36-2.

Hope that helps 

Jon

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2 hours ago, Electredge said:

if the crank trigger wheel has been replaced by a 36-2 aftermarket wheel the 99-00 Miata non VVT uses 3 teeth on the cam and is not currently a supported pattern, however you can remove the valve cover and cut off 2 of the 3 teeth on the cam gear fairly easily then you can make it work without any issues. 

@AdamwThis is the trigger setup I'm gonna get you the scope for, tons and tons of the existing miata's have already swapped out the OEM 4 tooth crank wheel for the 36-2.

Hope that helps 

Jon

Jon

This make sense, then would I just use the multitooth missing Trigger 1 pattern and then Trigger 2 as optical/hall with a falling edge or would I select the Mazda MX5 OB2 or something completely different?
 

Thanks

Chris

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You originally said you can’t see anything on the scope.  So you first need to fix the wiring so you have valid signals showing on the scope before you start messing with settings or cutting teeth off.  As Vaughan already said, this pattern you have will quite likely work with one of the Toyota modes without modifying anything, but we need to see a scope to confirm positioning of the teeth.

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On 4/1/2021 at 8:11 PM, Adamw said:

You originally said you can’t see anything on the scope.  So you first need to fix the wiring so you have valid signals showing on the scope before you start messing with settings or cutting teeth off.  As Vaughan already said, this pattern you have will quite likely work with one of the Toyota modes without modifying anything, but we need to see a scope to confirm positioning of the teeth.

I have got the scope to read signals now and have attached a few samples for you.
I changed the trigger and if the sensor was a optical/hall each time for the crank but not the cam. I am still not getting any spark or injectors working on cranking.

Also, for some reason Digital input 1 is showing as off but active, however it appears that this is not connected to anything when I locate the pin on the ecu. Not sure what is going on here. I spoke to my friend who did the majority of the wiring and he was informed to swap the polarity of the crank sensor by someone at Link incase this gives any strange scope readings (however I am not sure why he was told to do this)

 

Digital input question.jpg

 

Trigger Scope Log 2021-04-5 1;14;03 pm mazda MX5 - Reluctor.llg Trigger Scope Log 2021-04-5 1;15;29 pm mazda MX5 optical-hall.llg Trigger Scope Log 2021-04-5 1;16;58 pm 36-2 optical-hall.llg Trigger Scope Log 2021-04-5 1;17;58 pm UZFE VVTi optical-hall.llg Trigger Scope Log 2021-04-5 1;57;35 pm 1JZ VVTi - reluctor.llg Trigger Scope Log 2021-04-5 2;00;00 pm 1JZ optical-hall - rising edge.llg Trigger Scope Log 2021-04-5 2;00;00 pm 1JZ VVTi optical-hall - falling edge.llg Trigger Scope Log 2021-04-5 12;44;45 pm - 36-2 trigger - Reluctor.llg Trigger Scope Log 2021-04-5 12;47;57 pm -UZFE vvti Reluctor.llg Trigger Scope Log 2021-04-5 12;56;47 pm UZFE.llg

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Both trig 1 & 2 should be set to optical/hall with pull-up's on.  The cam sensor is not showing a usable signal in any of those scopes so I assume you didnt have the pull-up on?  Or maybe it is wired wrong. 

Leave it set to MX5 vvt trigger mode for now.  

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I have checked the settings and ran some trigger scopes.
I managed to get spark on the last two but the timing isn't right as after the engine was not cranked, spark continued for a second or two at most

Attached are todays scopes with the settings given above. 

Trigger Scope Log 2021-04-6 1;50;52 pm.llg Trigger Scope Log 2021-04-6 1;53;11 pm trigger 2 rising edge.llg Trigger Scope Log 2021-04-6 2;08;40 pm wires swapped on cam sensor with falling edge - engine has spark.llg Trigger Scope Log 2021-04-6 2;12;02 pm wires swapped on cam sensor with rising edge - Engine has spark spark.llg

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28 minutes ago, Adamw said:

Still not a usable cam signal.  It only varies between about 0.1 & 0.65V.  It should go to around 4V.  

the 1st two logs sit there... but the 2nd two sit at 9-10v... I assume a pullup was turned on?  but either way Adam is correct no cam signal is being seen.

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4 minutes ago, Electredge said:

but the 2nd two sit at 9-10v... I assume a pullup was turned on?

The 2nd two are titled something like "wires swapped", so it likely has battery voltage going direct into the trigger input.  Pull-up is 5V through a diode, so about 4.2V usually.

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1 minute ago, Adamw said:

The 2nd two are titled something like "wires swapped", so it likely has battery voltage going direct into the trigger input.  

The battery voltage has not been touched. The only two that got swapped were the trigger and ground, if that is any help.

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7 minutes ago, Electredge said:

looking from the back of the connector, how do you have it pinned? 

Left to right 
Red/White - Grey/Blue - Black/Blue for second set of scopes

Red/White - Black/Blue - Grey/ Blue for first set of scopes

 

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3 hours ago, Electredge said:

they you have a sensor problem, actual wiring problem, or the trigger teeth are broken or too far away 

I will do some further investigation. At least now I am getting spark and the fuel pump is running when cranking which is wasn't doing before. Once I have looked into this further I will report back. Thanks for your help so far!

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  • 4 weeks later...

A bit of a delay but some progress has been made:

1) Spark is present
2) Fuel is present
3) Crank Sensor is getting readings
4) Wiring replaced including plug for cam sensor
5) Cam sensor is new

 

However, It its trying to start but doesn't, just checking to see if something is still amiss with sensors or settings within the ecu.

I have attached a log. 

Chris 

Trigger Scope Log 2021-05-7 5;46;14 pm.llg

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