Crank but No Start - Mx5 NB1 Boosted

[BeefNugget]

I'm very new to tuning so feel free to point out the obvious (It would help actually).

So I've installed a second hand turbo kit with the following relevant electronics: electronic boost control, no 02 sensor (I've got an aem one installed but its not wired to the ecu), bigger injectors (prev owner said 1200cc but his tune had 700cc), Pnp G4X, and new IAT sensor.

I've loaded the base map for this car (mx5 nb1) and changed to fuel settings to mimic what the previous owner had in his g4+ (He repinned his harness for the g4+ but I've bought a new g4x so I can look at his tune but not use it). 

So the problem I'm having is that despite spark showing during ignition test and them smelling like fuel (So fuel is coming through at the least) there is no combustion.

I'll attach my tune and a quick log of the car being cranked. Thanks for any help, idk what I'm doing really.

Mazda MX5 NB1 1.8 G4X Xtreme Plugin - copied fuel.pclx PC Datalog - 2023-07-5 11;23;40 am.llgx

[Vaughan]

Your MAP sensor calibration or wiring is wrong, it's showing a MAP value of 56.1 and a BAP value of 103.6 with 0RPM, these values should be the same when the engine isn't running. Given it has a voltage of 0.52V I would lean towards that being a wiring thing.

I suspect those injectors are bigger than 700cc/min actual flow rate as the VE table values (Fuel table) seem weirdly low.

1 minute ago, Vaughan said:

Your MAP sensor calibration or wiring is wrong, it's showing a MAP value of 56.1 and a BAP value of 103.6 with 0RPM, these values should be the same when the engine isn't running. Given it has a voltage of 0.52V I would lean towards that being a wiring thing.

Actually I take that back sorry, it looks fine in the log but not in the saved runtimes in the tune

I assume you're still running the factory Coils? The log looks like it is happy, have you confirmed the fuel pump is running and that it has fuel pressure? do you get any noises like it is trying to run from the engine? have you done an injector test to make sure they are all working properly?

[BeefNugget]

Yep factory coils. MAP should be fine because it's the onboard 7 bar sensor. 

I can't hear the pump running, but there is definitely a smell of fuel.

I've just jumped the fuel pump relay through the diagnostics box and can hear it running, so I'm assuming that the fuel pump isn't running. In the g4+ user manual the attached image is shown. Is it possible that because I'm running no MAF the fuel pump is refusing to activate?

 

Ok so I started the car with the fuel pump relay jumped and it idled. I started the log after it started running cause I honestly thought it wouldn't work. It idled well but stalled when I gave it a blip of throttle.

PC Datalog - 2023-07-5 12;30;49 pm.llgx

[Vaughan]

The NA6 has the fuel pump relay through the MAF, the NBs do not, is it an NB1 chassis and wiring loom or is it an engine swapped NA6?

 

[BeefNugget]

17 hours ago, Vaughan said:

The NA6 has the fuel pump relay through the MAF, the NBs do not, is it an NB1 chassis and wiring loom or is it an engine swapped NA6?

 

It’s an nb1 chassis.
 

So the pump isn’t getting turned on by the ecu but still works fine. Not sure where to go from here.

[Vaughan]

Given that the previous owner repinned his harness to suit a G4+ I'm going to go ahead and assume that it was wired to suit a G4+ NA pnp. Do you now have a G4X NB1 pnp that you have changed the harness back to factory to suit?

I suspect the problem is to do with the re-pinning/setup in the ECU. My notes have the Fuel Pump wire listed as being Light/Green in the US and JDM models and being connected to the 3N pin on the ECU header, do you have a light green wire going into the ECU and if so which pin hole does it go into? if you remove this light green wire and ground it while the ignition switch is on the fuel pump should run.

[BeefNugget]

Sorry I should clarify. He repinned his harness for the g4+ but I still have the stock harness and hence the nb1 g4x.

I'll check for that wire now.

 

[BeefNugget]

Looks like there is no light green wire there (Red circle). However, looking at this site which is Australia specific (I'm in aus btw) (https://bartuneengineering.wordpress.com/mx-5-miata-information/australian-mx-5-nb8a-1999-2000-ecu-pinout/), it seems like the fuel pump relay is at 3P, which is a red and white wire (Purple Circle). According to the Link manual, this is where the fuel pump relay should be for euro spec cars.

  

[Vaughan]

Sweet, that lines up with my documentation, including the wire colour, do you have ignition 5 setup as Fuel Pump, does the pump prime at key on, does the pump turn on when ignition 5 test is turned on?

[BeefNugget]

Yep Ign5 is setup as fuel pump.

 

No priming with key on.

No change when Ign 5 test is on.

Also, whenever I turn the key on the egr solenoid (Part no. B69N18740) clicks several times, and then again after 3 or 4 seconds. Don't know if this is relevant.

[Vaughan]

If you remove that red with white stripe wire and ground it while the ignition switch is on does the fuel pump run?

If it doesn't can you try turning on the ign6 test to see if the fuel pump runs please

[BeefNugget]

Noob question, but how do I remove the wires from the connector easily?

Also where is a safe spot to ground the wire?

Oh and ign 6 is setup for the tacho, which is strange as the link manual says the tacho should be aux 2. 

[Vaughan]

8 minutes ago, BeefNugget said:

Noob question, but how do I remove the wires from the connector easily?

you need a very small flat head screwdriver or something else narrow and pointy, each row in that plug has a catch that keeps all the pins in and you undo this catch by prying out the bits on both ends so that it can bend away from the plug, each pin then has an individual tab that can be flicked out of the way allowing the wire and crimp to be pulled out the back of the plug, nothing should need to be forced particularly hard.

Alternatively just unplug the whole plug and slip a bit of wire into either the ecu side of it or the back of it and touch the other end of that wire to ground.

12 minutes ago, BeefNugget said:

Also where is a safe spot to ground the wire?

Any exposed metal surface that is attached to the chassis, I often use the metal pin on the door strap

13 minutes ago, BeefNugget said:

Oh and ign 6 is setup for the tacho, which is strange as the link manual says the tacho should be aux 2. 

Does your tacho work? I think I vaguely remember having the Tacho output set wrong in an earlyish copy of the sample map. a quick test of Aux 2 to Test On (PWM) with a frequency of 33Hz should show about 1000rpm (if my quick maths is correct).

Ign 6 being set to tacho would explain the egr solenoid pulsing at power on if it is doing a tacho sweep. The reason I asked about testing Ign 6 was just to see if the fuel pump wire was run to it instead of to one of the pins listed as fuel pump in our documentation.

[BeefNugget]

I think when I had the car running yesterday, I remember noting that the tacho wasn't working. 

15 minutes ago, Vaughan said:

Does your tacho work? I think I vaguely remember having the Tacho output set wrong in an earlyish copy of the sample map. a quick test of Aux 2 to Test On (PWM) with a frequency of 33Hz should show about 1000rpm (if my quick maths is correct).

Your quick maths was dead on haha. Does this mean I should switch the tacho from Ign 6 to Aux 2.

I'll ground the red and white wire now to test.

Oh quick question, I'm going to slip a wire into the plug and then ground it, so do I slip it into the back of the connector when it's still in the ecu. Or take the plug out, leave it out and ground the wire without the plug connected to the ecu. I'm assuming I'll have to turn the key to on either way to test.

[Vaughan]

9 minutes ago, BeefNugget said:

Your quick maths was dead on haha. Does this mean I should switch the tacho from Ign 6 to Aux 2.

 

yes

[BeefNugget]

Ok so I grounded the pin and I heard a relay under the dash switching and the pump running.

[Vaughan]

I have just looked at the schematic, there is a jumper on the ECU which is used to connect Ign5 to one pin or the other, move this jumper to the other location and it should all work.

[BeefNugget]

Awesome that fixed everything! I started the car and let it warm up before giving it some revs. I'll attach the log (It's in a zip because its slightly larger than the max upload). Does it all look correct? Also the AFR was reading about 12.8 at idle and stayed just above 14 after I gave it a rev.

Thanks so much for all the help.

6.7.23.zip

[castillaricardo]

The basics look ok, except for your fuel pressure settings. NBs use a returnless fuel system but yours is set to MAP Referenced at a lower pressure than stock. Is  your fuel system modified to fit these settings? In your log the Overrun Fuel Cut is activating at idle, and the Fuel and Ignition tables need boost rows.

You mentioned 1200cc injectors above, but the settings have 700cc. If the previous owner was running lower pressures as your map suggests that might explain why he used that number. You should look into this too because it would affect the whole map.

[Vaughan]

4 hours ago, castillaricardo said:

The basics look ok, except for your fuel pressure settings. NBs use a returnless fuel system but yours is set to MAP Referenced at a lower pressure than stock

Not all NBs, the Japanese NB1 and NB2s that I have dealt with had returns and my NZ new NB2 was returnless so would need confirming for that particular car.

 

[castillaricardo]

Ah, color me schooled. Thanks for that. Then yes, he’ll need to verify his setup.

[BeefNugget]

Ok thanks! Considerring that my fuel pump was euro spec I'll assume that returnless is the correct setting. Is there anything that also needs to change with this change?

Sorry if I'm asking dumb questions, a lot of this is going straight over my head cause this is the first experience I have with tuning software (or tuning in general).

I'm also copying over the prev owner's boost control settings (I'll attach the tune). Do these look right? I'm using a turbo smart 4 port solenoid but only using the bottom two ports (gotta make do with what I have).

Working-boost.returnless.pclx

[BeefNugget]

I've changed the fuel and ignition tables to copy the prev tune (I'll attach mine and the prev tune) and took a log of idling and a bit of a rev. Does it all look in order. There was a bit of bouncing at idle between 1500~1600 rpm, but you'll see that in the log.

6.7.23-returnless-afr.change.pclx Stock_Tune.pclr PC Datalog - 2023-07-7 1;42;23 pm.llgx

[castillaricardo]

Don't assume that it is. Look at your engine bay, right side of the car, and check if you have one fuel feed and one EVAP, or if you have one feed, one return and an EVAP. See below for some examples. I haven't seen a return-style NB in person, but it should be similar.

 

Return style:

Returnless style:

The EVAP line is the one little pipe sticking up that's disconnected in the second picture.

As for your tune:

- I don't know what the fuel pressure is for a return system, but the returnless is expected to be 400kPa/58psi. I'm not sure it matters, but I like having the settings correct.

- I wouldn't use someone else's boost control duty cycle unless you have the identical valve and overall setup and have the car tuned. For now, just have it set at 0 duty-cycle and tune on wastegate pressure, and setup a MAP Limit right above what your wastegate spring is.

- In your log, the overrun fuel cut is still engaging at idle, causing the oscillations you saw as it pulls and adds ignition timing. Set it to disable at 2000RPM and your idle will likely improve.

- Your idle valve needs tuning. Start with 500Hz frequency, and you could set it to closed-loop. Your dashpot should likely be lower as well.

- You really need to have a wideband connected to the ECU. I strongly suggest you get a CAN based controller.

- Consider a fuel pressure sensor. Link can use it to adjust fueling if something goes wrong with the pressure.

Take a look through the help file. It really does a great job of explaining every setting and is one of the best things about Link ECUs. Modelled fuel mode has a few moving parts, but really go through the help file as it will explain all of it. For example, your IAT Correction, but modelled mode has a charge approximation table that takes care of the IAT corrections if setup correctly. It's up to you and your tuner how to set this up, but just food for thought. Your car starts and mostly idles so that's a good start.

[BeefNugget]

Thanks for taking the time to write this all up.

So it looks like my car matches the first pic (Return system) so does this mean MAP referenced was the correct setting.

Also, I do have the exact same setup as prev owner as I bought everything off him, so boost control setting should work but I'll follow your advice anyway. When you say change it to 0hz do you mean the PWM freq, cause if so it says the min is 1. Also not quite sure if I set the MAP limit correctly, I've attempted to set it to 10 in my tune. 

 

For the fuel cut table I have it changed like so:  Is this what you meant?

And yep totally agree about wideband setup. Currently have one installed and showing on a gauge but will be wiring it to CAN hopefully soon (Do you know where to get the connector for the board from I'd like to solder up my own connection but cant find the right plug).

So I've made all these changes and now the car won't start. I'll attach the log (EDIT: REMOVED LOG FOR UPLOAD SPACE).

Attaching the updated tune if you need it.

 

Wait, I had the MAP limit at 70 kpa not 170. Now it idles properly.