Hi MiataTurbo,
I posted in this forum a few weeks ago with a no-spark issue that I have since solved. I'm now tackling a no-start issue, so I'm starting a new thread.
I have a 1991 Miata with a 2002 VVT engine in it. I rebuilt the engine myself with new pistons, rings and ARP head studs and had each cylinder bored out and honed. The engine is all in the car, wired up, but won't start. Without spark plugs installed, the engine cranks freely. With plugs installed, I get about 3 or 4 cranks and then the engine stops turning, then it restarts with another 3 or 4 cranks and then stops again.

I am going to attach a screenshot of my composite logger below. It does not look like any other composite logger I've ever seen.

If anyone has any thoughts on why my car might not be starting, I am all ears. Build specifications are below, and Tunerstudio settings are below that.



Build info:
-1991 Miata
-2002 VVT engine (newly rebuilt)
-NA6 5 Speed transmission
-DW600 injectors
-DW200 Fuel Pump
-Speeduino NA6 PnP board w/ Arduino 2560 Mega
-New NGK spark plugs
-New NGK Plug wires
-Coil Pack+Ignitor from the '91 chassis
-Cam sensor + crank sensor in place of the NA6 CAS

Speeduino settings:
-Base Map for '01-'05 (non MSM)
-Ignition
---Load source ---> MAP
---Wasted Spark
---Crank Advance Angle ---> 10 degrees
---Spark outputs trigger ---> Going Low
---Locked Timing ---> Off
---Use new ignition mode ---> On (https://wiki.speeduino.com/en/decoders/Miata_99)

-Trigger Setup
---Pattern ---> Miata 99-05
---Trigger Angle ---> -10* ATDC (aka 10* BTDC)
---Trigger Edge ---> Falling (for both primary and secondary sensor)
---Trigger Filter ---> Weak
---Re-sync every cycle ---> Yes

More info:
-Fix crank timing with trigger ---> On (https://wiki.speeduino.com/en/decoders/Miata_99)
-If I crank the engine and pull the spark plugs afterwards, they are wet. So I do have fuel.
-I do get occasional ignition events. I'll hear little pops and bangs as I'm cranking the engine.
-My VVT solenoid is not plugged into anything at the moment. I have yet to sort out the wiring for it, so I am leaving it unplugged for the time being (until I can start the car)
-I'm reusing the cam sensor that came with the engine
-New crank sensor
-When I crank the engine, Tunerstudio registers that the engine is cranking and that it has sync as well

Any help would be greatly appreciated!

 

Battery is probably weak. Tuner studio has nothing to do with the engine not cranking.

 

I'll try a battery from another car of mine, see if that helps. For what it's worth, my battery lives on a charger/maintainer until I'm ready to turn it over.
Does everything else look right? It does to me, but this is my first time doing this so I wouldn't necessarily know right from wrong.

 

I didn't even look at the tune because there really isn't anything there that can keep it from cranking. There is a ground that goes from the back drivers side corner of the engine to the shelf on the body. Make sure that's hooked up properly.

 

Change your cranking advance under spark settings to 5. Theres a bunch of other stuff wrong with the tune, but let's start there.

 

Curly, I went ahead and changed the cranking advance to 5. Correct me if I'm wrong, but I think that setting gets overriden by the "fix cranking timing with trigger" setting that I'm supposed to have "on" according to https://wiki.speeduino.com/en/decoders/Miata_99

What else do you see wrong with the tune?

 

Yeah if you have that off it uses your ignition table I think, which is even worse. My point is you should try less cranking angle to see if it cranks smoother, you may be having starter kickback. Monitor advance while cranking, and make whatever change is required for less cranking timing on your setup

 

Thank you Curly, lowering the cranking advance eliminated the kickback. And thank you Spartan for pointing out the weak battery, you were right. It cranks much faster (with a better battery) and smoother (lower cranking advance), but still no start. Attached is the latest composite logger.

 

I'm not sure what the logic (software) behind the sync is, but I've never seen a cam sensor have two different pulse widths like that. Again not sure if it matters, but that's weird.

You're using the stock VVT cam sensor off the back of the intake cam?

 

Yeah, the two pulses are weird. I'm not sure what that's about either.
I am using the stock cam position sensor, and the software is Speeduino 2020.02.

 

Looks like the double cam pulse is normal.

 

As you have a 91, is your car wired for seq as you got it in TS? If its not, then try using batch injection under "engine constants".
For better drivability and no headache while tuning AE, try to switch from cycle average to instantaneous under "map sample method", many other speeduino users could not get AE to work fine without this change.

Your Warmup Enrichment is somewhat reverse? Gets richer when the engine is hot and leaner, when its cold?
Try PWM open loop idle for your first starts, helped me out a bit.
Your trigger angle is -12°, isn't that a bit off for the NB setup? Check timing again with a light, maybe you are using the wrong marks on the crank pulley (10° off, as 2° seems more likely).

Report back!

 

Hey der_vierte, my car is wired for sequential injection, and the appropriate modification was made to the Speeduino board. I've used the TS Hardware test mode to confirm that all four injectors are capable of firing. Thank you for pointing out the WUE fault, I have since fixed it. PWM Open loop idle has been selected also.

Still no start. It cranks freely and quickly (thanks to new battery), but I no longer have ignition events happening. Before it felt like it was almost going to start, but not any longer.

Regarding my trigger angle, I don't believe there is a way to check timing without the engine running. Please correct me if I am wrong. If I am right that I can't check timing without the car running, what number should I input as my trigger angle until I can get it running and make that change with the help of a timing light?

 

With NB sensors it really should be close enough to start without having to do anything other than have the appropriate trigger settings. Please post a log of it cranking and your current tune.

 

Here is a datalog I just took when cranking. Also attached is the tune file that I am using with changes that helpful people on this thread have suggested. Thank you!

 

Where did you get your trigger edge settings? I don't think they're right.

Why are you using the new ignition mode?

 

I was grasping at straws with the trigger edge settings, saw someone else had luck making that switch so I figured why not try. No luck. It's set back to "falling" for primary and secondary sensors.

New ignition mode because https://wiki.speeduino.com/en/decoders/Miata_99 (see "tunerstudio configuration"). I'm using the 1.6 coil pack w/ external igniter, not the semi-cop's that come with the 2002. Does the "new ignition mode" only apply if you're using the semi-cop's?

 

Bump