No spark while cranking (resolved)

[240trevor]

I've done a ton of research trying to sort this out but Im stumped. 

I'm not getting any spark while cranking. Ignition test works flawlessly and I have confirmed spark with spark plug and timing light. As far as I can tell there is no ignition cuts active. I have tried both a Nissan 360 and AEM 24 trigger disk with recommended settings. I am reading RPM while cranking. Trigger scope doesn't look the cleanest but has 24 in trig 1 as it should. I am getting trigger error every other rotation from the looks of it. Initially I was not getting power to the CAS so for now it is wired directly to 12v. I have tried every combination of trigger settings I could find from my research. Coil packs are VQ35DE with ignitor bypass.

TPS is behaving strangely  and is unplugged (Likely faulty TPS)

IAT and ECT appear to be reading incorrectly (if this was my problem I would be seeing ign cut, correct?)

Crank rpm is relatively slow. Battery/starter wiring and grounding is proper, I think the slow crank is related to a faulty starter but its always started up like this on my RS Enthalpy ECU. 

Keep in mind this is my first attempt at working with a standalone so I apologize if the problem is obvious. I want to learn as much as possible, so any information or advice is greatly appreciated.   

 

S13 SR20DET

AEM 24T TRIGGER DISK

VQ35DE COILPACKS W/IGNITOR BYPASS

G4X MONSOON X

Startup 2.pclx Trigger Scope - 2024-06-16 10;58;59 pm.llgx PC Datalog - 2024-06-16 11;32;35 pm.llgx

[240trevor]

Update: With trigger 2 set to "Falling", trigger error only occurs when stopping cranking. Still no spark.

Update: With spark plugs removed trigger scope is much more consistent. New trigger scope log attached with changes: removed spark plugs and changed trigger 2 edge to falling. 

Trigger Scope - 2024-06-16 11;58;59 pm No spark plugs.llgx

[Vaughan]

1 hour ago, 240trevor said:

I'm not getting any spark while cranking. Ignition test works flawlessly and I have confirmed spark with spark plug and timing light. As far as I can tell there is no ignition cuts active. I have tried both a Nissan 360 and AEM 24 trigger disk with recommended settings. I am reading RPM while cranking. Trigger scope doesn't look the cleanest but has 24 in trig 1 as it should. I am getting trigger error every other rotation from the looks of it. Initially I was not getting power to the CAS so for now it is wired directly to 12v. I have tried every combination of trigger settings I could find from my research. Coil packs are VQ35DE with ignitor bypass.

I can see Dwell being output from the ECU in your PC Log and your Trigger scopes look good, definitely would be going falling edge for Trigger 1 & Trigger 2, how are you determining no spark? visually with a plug out and grounded or with a timing light?

Are the coil packs losing power when you crank the engine?

[240trevor]

9 hours ago, Vaughan said:

I can see Dwell being output from the ECU in your PC Log and your Trigger scopes look good, definitely would be going falling edge for Trigger 1 & Trigger 2, how are you determining no spark? visually with a plug out and grounded or with a timing light?

Are the coil packs losing power when you crank the engine?

I have confirmed spark while in test mode both with a grounded spark plug and with a timing light and also observed no spark while cranking using the same methods.

Coilpacks are wired to constant 12v so I’m confident they are seeing 12v while cranking but I will check to be sure.

[240trevor]

@VaughanUpdate: I have confirmed coil packs have 12v power. The voltage does drop to 10.6 while cranking. 

[Adamw]

The logs show the ecu is commanding a spark.  I cant think of any other logic that would cause no spark when cranking.  Do you have an LED test light to confirm there is a pulse reaching the coils?  The dwell is possibly a bit too long, you could temporarily try a flat 4.0ms in the dwell table. 

And although RPM should have no effect on the spark issue (I think the minimum is about 20RPM from memory), I think you are going to need to fix the low cranking RPM to get it to start reliably.  Even with the spark plugs out you only have an average of about 120RPM, it should be at least double that with the plugs out.  With plugs in I would expect >200RPM typically.

[240trevor]

1 hour ago, Adamw said:

The logs show the ecu is commanding a spark.  I cant think of any other logic that would cause no spark when cranking.  Do you have an LED test light to confirm there is a pulse reaching the coils?  The dwell is possibly a bit too long, you could temporarily try a flat 4.0ms in the dwell table. 

And although RPM should have no effect on the spark issue (I think the minimum is about 20RPM from memory), I think you are going to need to fix the low cranking RPM to get it to start reliably.  Even with the spark plugs out you only have an average of about 120RPM, it should be at least double that with the plugs out.  With plugs in I would expect >200RPM typically.

Are you suggesting I disconnect a coil pack and setup a test light on the ignition signal when cranking? As mentioned I have confirmed spark in “test” mode with both a timing light and spark plug.

I will try your suggestion in regards to the dwell table.

When it comes to the starter I will have to order a new one but I think we both agree it’s likely not the current issue. It did cause hard start issues on my old setup and I know it needs to be addressed.

 

Thanks for the help so far, I’ll be sure to update when I make the changes or if I find a solution. 

[Adamw]

2 hours ago, 240trevor said:

I disconnect a coil pack and setup a test light on the ignition signal when cranking?

Yes, or you can leave the coil connected and "back probe" with a needle.

 

2 hours ago, 240trevor said:

As mentioned I have confirmed spark in “test” mode with both a timing light and spark plug.

 That doesnt rule out things like for example a large ground offset when the starter is engaged due to a weak ground or similar.  Whereas if you can see a pulse with a test light but see no spark at the same time then you can be a bit more confident on what can be ruled out. 

[240trevor]

Update: While testing spark again I noticed that I am currently getting spark while cranking visually (Spark plug). I'm not sure if it was something I changed or if I just didn't see it the last time I checked. While I am now getting spark my timing light is still not flashing while cranking. It does flash in ignition test mode and is a fairly new known working light. 

I tried adjusting the dwell table to 4ms as @Adamw suggested with no change.

My new starter arrives tomorrow, in the meantime I did connect 2 additional grounds to both the engine and starter body to confirm solid grounding with no change. 

Thank you for the information so far, it is greatly appreciated. 

[Vaughan]

Do you have the timing light trigger of the ignition loom wire loop? You typically need to have it over an ignition lead between the coil and spark plug instead of over that timing loop.

[240trevor]

2 hours ago, Vaughan said:

Do you have the timing light trigger of the ignition loom wire loop? You typically need to have it over an ignition lead between the coil and spark plug instead of over that timing loop.

I use an old spark plug wire between the coil pack and spark plug. I find it to be more accurate then the loop of wire that sticks out of the loom provided by Nissan for timing.

For context I have over a decade of experience with these cars. I’m just new to tuning and standalone computers in general.

I got a little impatient and tried to start the engine. It idled horribly for a moment and the timing light did work in that time. Tried to start it again and smoked the starter. Pulled plugs to see a pool of E85.

I have alot to learn.

Decided to call it a night lol.

[240trevor]

Resolution: After removing the old starter it appears to have been damaged at some point in time likely from poor grounding. (signs of overheating on the contact stud) New starter is spinning at 255RPM and I was finally able to get a timing signal to set base timing. I don't think the issue was related to low RPM but rather a problem while cranking related to the starter. and grounding.

Trigger offset only needed to be adjusted by -1 which was surprising to me.

Thanks for all the help @Adamw @Vaughan I cant thank you guys enough. I do my best to try and sort any issues on my own but You will likely be seeing more from me in the future.