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PSU_Crash wrote: Wed Mar 04, 2026 3:53 pm
I'm not familiar with the F9 ECU, but on others I have setup there is a cranking RPM Threshold. Below that, no spark. Although I do see the timing advance coming in, so probably not likely.
Does the F9 take the place of the factory ignition module? I have had a dead ignitor on other projects in the past that acted just like you are saying.
The F9 is a modernized clone of the original DME -- virtually identical but with modern surface mount components.
I'll take a look at the logs, but as johnb said above it sounds like he has a pulse...
PSU_Crash wrote: Wed Mar 04, 2026 3:53 pm
I'm not familiar with the F9 ECU, but on others I have setup there is a cranking RPM Threshold. Below that, no spark. Although I do see the timing advance coming in, so probably not likely.
Does the F9 take the place of the factory ignition module? I have had a dead ignitor on other projects in the past that acted just like you are saying.
The F9 is a modernized clone of the original DME -- virtually identical but with modern surface mount components.
I'll take a look at the logs, but as johnb said above it sounds like he has a pulse...
If this helps any the 1 value on the fly wheel rpm error in the F9T software was highlighted yellow while trying to start. Im not savvy on all this data yet, but a 1 in a fly wheel rpm error column that is yellow doesn’t seem good to me.
I agree, that doesn't seem good.
After downloading the FocusOBD software, I can't figure out how to open a datalog to take a look. Having a tooth/trigger log would be ideal, if that exists ... again, F9 noob, but I'm learning
PSU_Crash wrote: Thu Mar 05, 2026 4:20 pm
I agree, that doesn't seem good.
After downloading the FocusOBD software, I can't figure out how to open a datalog to take a look. Having a tooth/trigger log would be ideal, if that exists ... again, F9 noob, but I'm learning
Here’s F9T YouTube video on how to record data and get the file.
I looked at your log. It shows an injector pulse and RPM while cranking, which strongly suggests the DME has valid speed and reference sensor signals (and power). So — as johnb already pointed out based on the tach bounce — that generally points toward the ignition system and away from issues like no power through the DME relay, bad speed and reference sensors, etc.
The sensor error you show probably occurred while cranking. I have the F9 DME too and confirmed my logs often show a small single-digit number of errors as well.
I’d check the negative side of the coil and see if there is a pulse (scope, LED, test light, etc.). If the coil has power and a pulse, but no spark at all, then that points to the coil (absent some unlikely scenario where the DME is pulsing the circuit but unable to supply enough current to create spark).
If you do not have a pulse at the coil, then I’d check for continuity (essentially zero resistance) between Pin 1 of the main DME connector and the green wire at the coil.
If there’s no continuity, then you need to find where the break is. That signal goes through the 14-pin Kostal (aka bulkhead) connector above the brake booster. I’d start by making sure the 14-pin connector is fully seated and that the thick green wire is in the Pin 1 position (on both the male and female sides) of that connector. Then see if Pin 1 of the DME connector ohms out to the DME/male side of Pin 1 in the Kostal connector (where the thick green wire should be). If that checks out (i.e., near-zero ohms), then test from the engine/female side of Pin 1 at the Kostal connector to the green wire at the coil. That will tell you whether the break is in the DME harness, the 14-pin connector itself, or the engine bay harness.
If you do have continuity all the way from Pin 1 of the DME connector to the green wire at the coil, then the only other possibility I can think of is a bad ignition driver (transistor) inside the DME. That seems unlikely since it's a new DME, but stranger things have happened. The RPM signal being logged by the F9 is almost surely derived from the DME tach output on Pin 21, and my reading of the factory DME schematic suggests Pin 21 shares a timing source with the Pin 1 ignition signal, but that Pin 21 would continue to pulse even if the transistor driving Pin 1 were dead. I would expect that to be the same in the F9 DME, but can’t say for sure.
Tom wrote: Thu Mar 05, 2026 7:01 pm
I looked at your log. It shows an injector pulse and RPM while cranking, which strongly suggests the DME has valid speed and reference sensor signals (and power). So — as johnb already pointed out based on the tach bounce — that generally points toward the ignition system and away from issues like no power through the DME relay, bad speed and reference sensors, etc.
The sensor error you show probably occurred while cranking. I have the F9 DME too and confirmed my logs often show a small single-digit number of errors as well.
I’d check the negative side of the coil and see if there is a pulse (scope, LED, test light, etc.). If the coil has power and a pulse, but no spark at all, then that points to the coil (absent some unlikely scenario where the DME is pulsing the circuit but unable to supply enough current to create spark).
If you do not have a pulse at the coil, then I’d check for continuity (essentially zero resistance) between Pin 1 of the main DME connector and the green wire at the coil.
If there’s no continuity, then you need to find where the break is. That signal goes through the 14-pin Kostal (aka bulkhead) connector above the brake booster. I’d start by making sure the 14-pin connector is fully seated and that the thick green wire is in the Pin 1 position (on both the male and female sides) of that connector. Then see if Pin 1 of the DME connector ohms out to the DME/male side of Pin 1 in the Kostal connector (where the thick green wire should be). If that checks out (i.e., near-zero ohms), then test from the engine/female side of Pin 1 at the Kostal connector to the green wire at the coil. That will tell you whether the break is in the DME harness, the 14-pin connector itself, or the engine bay harness.
If you do have continuity all the way from Pin 1 of the DME connector to the green wire at the coil, then the only other possibility I can think of is a bad ignition driver (transistor) inside the DME. That seems unlikely since it's a new DME, but stranger things have happened. The RPM signal being logged by the F9 is almost surely derived from the DME tach output on Pin 21, and my reading of the factory DME schematic suggests Pin 21 shares a timing source with the Pin 1 ignition signal, but that Pin 21 would continue to pulse even if the transistor driving Pin 1 were dead. I would expect that to be the same in the F9 DME, but can’t say for sure.
Thank you so much for the long and detailed troubleshooting. I have pretty much done all that but I have bought a test lead kit for my multimeter and a scope. So this weekend I am going to meticulously go back through and recheck everything you just laid out. Again thank you so much for your help. Here’s a pic of what you’re helping with for inspiration. Lol.
Tom wrote: Thu Mar 05, 2026 7:01 pm
I looked at your log. It shows an injector pulse and RPM while cranking, which strongly suggests the DME has valid speed and reference sensor signals (and power). So — as johnb already pointed out based on the tach bounce — that generally points toward the ignition system and away from issues like no power through the DME relay, bad speed and reference sensors, etc.
The sensor error you show probably occurred while cranking. I have the F9 DME too and confirmed my logs often show a small single-digit number of errors as well.
I’d check the negative side of the coil and see if there is a pulse (scope, LED, test light, etc.). If the coil has power and a pulse, but no spark at all, then that points to the coil (absent some unlikely scenario where the DME is pulsing the circuit but unable to supply enough current to create spark).
If you do not have a pulse at the coil, then I’d check for continuity (essentially zero resistance) between Pin 1 of the main DME connector and the green wire at the coil.
If there’s no continuity, then you need to find where the break is. That signal goes through the 14-pin Kostal (aka bulkhead) connector above the brake booster. I’d start by making sure the 14-pin connector is fully seated and that the thick green wire is in the Pin 1 position (on both the male and female sides) of that connector. Then see if Pin 1 of the DME connector ohms out to the DME/male side of Pin 1 in the Kostal connector (where the thick green wire should be). If that checks out (i.e., near-zero ohms), then test from the engine/female side of Pin 1 at the Kostal connector to the green wire at the coil. That will tell you whether the break is in the DME harness, the 14-pin connector itself, or the engine bay harness.
If you do have continuity all the way from Pin 1 of the DME connector to the green wire at the coil, then the only other possibility I can think of is a bad ignition driver (transistor) inside the DME. That seems unlikely since it's a new DME, but stranger things have happened. The RPM signal being logged by the F9 is almost surely derived from the DME tach output on Pin 21, and my reading of the factory DME schematic suggests Pin 21 shares a timing source with the Pin 1 ignition signal, but that Pin 21 would continue to pulse even if the transistor driving Pin 1 were dead. I would expect that to be the same in the F9 DME, but can’t say for sure.
After following everything Tom wrote and everything checking out good I took the DME out and opened it up and found something burnt. Going to send it back to F9T and have him fix it and see if he can tell me how this could have happened. Was it something on the new Kroon harness that I need to check before plugging in the repaired DME
Everything checked out good -- meaning you were getting a pulse at the coil but it still wasn't generating a spark?
Or no spark despite continuity from DME pin 1 to the green coil wire?
Can you post a close up of the burned component? Might be able to see what it is/was... I'd be surprised if the Kroon harness weren't perfect, but I would check that bulkhead connector over the brake booster to make sure all the pins and wires seem right. If I get a chance I'll pull my F9 DME and see if I can figure out what burned on yours -- that may narrow down the hunt for what caused that.... Sorry this happened but at least you found it and can get back on track to fire up that motor. (Gives you plenty of time to ensure you've built oil pressure... )
You might also check to ensure neither coil wire is accidentally grounded with the DME disconnected. Takes quite a bit of current to do that...
Tom wrote: Sat Mar 07, 2026 8:25 am
Everything checked out good -- meaning you were getting a pulse at the coil but it still wasn't generating a spark?
Or no spark despite continuity from DME pin 1 to the green coil wire?
Can you post a close up of the burned component? Might be able to see what it is/was... I'd be surprised if the Kroon harness weren't perfect, but I would check that bulkhead connector over the brake booster to make sure all the pins and wires seem right. If I get a chance I'll pull my F9 DME and see if I can figure out what burned on yours -- that may narrow down the hunt for what caused that.... Sorry this happened but at least you found it and can get back on track to fire up that motor. (Gives you plenty of time to ensure you've built oil pressure... )
You might also check to ensure neither coil wire is accidentally grounded with the DME disconnected. Takes quite a bit of current to do that...
Sorry I wasn’t clear on that. All wires ohmed out good and I did make sure none of the wires were going to ground. After all the checks still no pulse on the green coil wire so that when I opened up the DME
After following everything Tom wrote and everything checking out good I took the DME out and opened it up and found something burnt. Going to send it back to F9T and have him fix it and see if he can tell me how this could have happened. Was it something on the new Kroon harness that I need to check before plugging in the repaired DME
Something definitely shorted out on you. That looks like a surface mount resistor, although it's impossible to tell for sure now. Surprised they don't have components labeled in the PCB silk screen. Curious to hear what the Focus 9 guys have to say. Probably safe to say that's part of the ignition circuit.
My bets are on install error, unfortunately, not the harness. Power was on the F9 at some point and a wire was grounded (or powered) inadvertently. No shame in that. We have all been there.
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