Coyote Gen 4 start-up issue

[sellig]

Good morning Forum,
My step-son and I are trying to troubleshoot the engine refusal to start.
He put the current situation in the following words:

My step-dad is building a pretty nice MK4 roadster with a gen 4 coyote crate engine-TKX manual gearbox from Fortes/Ford performance. The build is in its last phase right now, but we had no luck starting the engine yesterday.
We might need help since we are out of ideas. Here is what we have done:
Engine harness has been connected to the RF harness
• orange wire from ‘ignition’ on the key switch to the light green wire of the Ford harness for waking up the ECM/PCM (which should prime the fuel pump)
• light blue wire from ‘start’ on the key switch to the light blue wire in the Ford harness for the starter request signal
• Thick gauge green wire from the Ford harness is connected to the relay (orange wire cut in half and spliced to the green wire to activate the fuel pump relay and leverage the roll over switch from the RF harness
Here are the symptoms:
• Car cranks fine when the key is on start
• Throttle-by-wire pedal is functional once the key is on ignition
• Fuel pump does not prime
• No spark when we crank the engine
For the fuel pump (because we have read a lot of posts on this forum related to the same issue of not being able to start the Coyote, thank you all btw!!!!):
• The RF circuit works fine. If we put 12v on the orange wire on the relay, the pump primes to a nice 65psi in no time
• In the ford PCM, all the relays and fused were checked and are functioning
• In the Ford PCM, there is power to all fuses and relays so power to the PCM is good
• In the Ford PCM, if we put power to the White/Yellow wire coming out the ECM, it triggers the pump
For the ECM:
• The light green wire gets a pretty good 12v signal when the car is in ignition and start
• Like I said earlier, the Throttle pedal is active, so the ECM most probably has a tune
Error messages from the OBDII port:
• After the initial attempt at cranking, we checked for OBDII with a cheap OBDII scanner, and we got a ‘P06B8: Internal Control Module Non-Volatile Random Access Memory (NVRAM) Error’ which we cleared and never reappeared
• If we disconnect sensors, like the MAF sensors, we get error codes, so this works
• Interesting observation: the OBDII scanner does not seem to access all the modules (like the fuel control module). I am not super familiar with OBDII scanners and the Ford architecture, so it might be fine.
Any help, even simple suggestions, is more than welcome. We need this bad boy running to terrorize the neighborhood!

[Indy Shu]

Inertia switch?

[Mike.Bray]

I'm not an expert on the Coyote but is the reluctor ring on the end of the crank installed? And the sensor? I know this has been an issue before.

[Nigel Allen]

Do you see RPM on the OBD reader when cranking? If zero RPM, the crank position sensor or reluctor ring may be an issue. This would certainly inhibit spark.

Fingers crossed for an easy fix.

[edwardb]

The fuel pump runs very briefly at startup and it's easy to miss. Especially for a very first start in a new engine it may not be enough to fil the lines, rails, etc. A relatively simple method is to put +12V on the fuel pump so it runs continuously. That will fill the lines plus you can check the pressure at your regulator and adjust if necessary. With the pump running I'd bet on it starting. Assuming your RF fuel pump relay/wiring is correct, you should be able to use that setup for subsequent starts.

The crate motor setup doesn't use the returnless computer controlled fuel pump. You won't see anything in the ODB2 data for it. Good luck.

[Blitzboy54]

When you say the engine turns over what exactly does it do? If you turn the key does it crank indefinitely or does it turn over 3 or 4 times then stop on its own while the key is still in the ignition position?

If it’s the former I would do as Paul suggested and run your fuel pump independently with a power supply or battery then crank it over. If it’s the latter I would be concerned you are either missing your pulse ring or maybe the crank position sensor is either damaged, not plugged in or missing.

[TXeverydayDad]

Hopefully it’s just as simple as lack of fuel in the lines. Good luck with the troubleshooting.

[michael everson]

Every GEN 3 I have installed takes forever for the first start. Sometimes as much as 5 minutes off and on of cranking. This is regardless of fuel pressure. I would keep trying. Do you get any hint of combustion? Like others said, if you assembled it yourself, was the crankshaft reluctor ring installed? Its behind the flywheel. You might be able to remove the sensor and look down the hole for it.

Mike

[sellig]

the inertia switch is fine. We were hoping it was just the culprit at first, but not.

[sellig]

I'm not an expert on the Coyote but is the reluctor ring on the end of the crank installed? And the sensor? I know this has been an issue before.

I’m guessing there’s the reluctor ring on the crankshaft. I bought the engine assembled with the gearbox to Fortes. I’m going to check it.

[sellig]

Do you see RPM on the OBD reader when cranking? If zero RPM, the crank position sensor or reluctor ring may be an issue. This would certainly inhibit spark.

Fingers crossed for an easy fix.

As we don’t have fuel pump on and any sparks, the reluctor ring sensor could be the issue. Will check it for sure

[Mike.Bray]

Reluctor ring install https://thefactoryfiveforum.com/showthread.php?51580-Removing-the-TKX-without-pulling-the-engine-w-IRS&highlight=mbufford

You need spark and fuel to run, these are handy for verifying the spark part https://www.amazon.com/dp/B01HU2L1NU?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

[Blitzboy54]

If you pull the crank position sensor you can see down inside with a flashlight. You will be able to see if it’s there or not.

[edwardb]

As we don’t have fuel pump on and any sparks, the reluctor ring sensor could be the issue. Will check it for sure

I can only say again the pump runs very briefly when you first turn the key on. It's easy to miss and think the pump isn't working. It won't do that brief run again until you turn everything off and the system resets after 10 seconds or so. Pretty sure the computer doesn't light the plugs until fuel is detected. But not 100% on that. Regardless, many have completed their first start by hot wiring the fuel pump as I described before. It's low risk. Once you have fuel pressure it just returns the unused fuel to the tank. Also allows you to check your regulator as that could be contributing. Of course check for the reluctor ring has others have suggested. Given that your setup is from Forte I'd be surprised if it's not there. He's done a bunch of these things.

[Blitzboy54]

I can only say again the pump runs very briefly when you first turn the key on. It's easy to miss and think the pump isn't working. It won't do that brief run again until you turn everything off and the system resets after 10 seconds or so. Pretty sure the computer doesn't light the plugs until fuel is detected. But not 100% on that. Regardless, many have completed their first start by hot wiring the fuel pump as I described before. It's low risk. Once you have fuel pressure it just returns the unused fuel to the tank. Also allows you to check your regulator as that could be contributing. Of course check for the reluctor ring has others have suggested. Given that your setup is from Forte I'd be surprised if it's not there. He's done a bunch of these things.

Also to follow up on Paul's point here. It's a good idea to hotwire your fuel pump before first start even if you don't have an issue. That way you can set the regulator pressure without the hurried stress of trying to get it just right while the engine is running. It also gives you the opportunity to inspect all your fuel lines for leaks without engine or exhaust heat. It's a good practice for any build not using a mechanical pump.

[edwardb]

Stupid questions -- how much fuel in the tank? Ideally several gallons at least.

[TXeverydayDad]

I just primed my fuel system today on my Gen4x and it took a good 15-20 seconds for the fuel rail to completely fill up, so if you haven’t run the fuel pump like Paul suggested, I’d recommend trying that first.

[sellig]

Bonjour everybody,
Thank you all for your valuable comments.
The engine finally started smootly.
As we ran out of battery, we were thinking of a missing permissive condition to start and we began to doublecheck and look at any rootcause.
The end result is that the fuel pressure has increased to 68psi without hearing the fuel pump, like said Edward and i kept to crank long enough to finally start the engine, like said Mickael, it seems Gen 4 is not different than Gen 3.
I had 5 gallons of fuel.
It was my first thread and I’m really astonished of the responsiveness and accuracy of your replies. It helped a lot. Thank you so much again and have a nice day.
I’m going to try to put a video of the start-up in the thread when I figure out how.

[TXeverydayDad]

Congratulations! Glad to hear it started smoothly in the end! Looking forward to seeing the video!

[sellig]

https://photos.app.goo.gl/7mVsjqBUeRjcZh7g6

Here’s the video of the start-up. Hope you can see it.
No sign of leaks.
No overheating.
RPM gauge remains at zero (4PPR mode, I will try the other modes), Oil pressure seems high but oil was cold and it’s a break-in oil (supplied by Fortes) with high viscosity I guess.
I’m going for a small road test in the street to check breaks, noises and feelings. don’t want to cross the way of the authority as the car is not registered yet.

[JeffP]

https://photos.app.goo.gl/7mVsjqBUeRjcZh7g6

Here’s the video of the start-up. Hope you can see it.
No sign of leaks.
No overheating.
RPM gauge remains at zero (4PPR mode, I will try the other modes), Oil pressure seems high but oil was cold and it’s a break-in oil (supplied by Fortes) with high viscosity I guess.
I’m going for a small road test in the street to check breaks, noises and feelings. don’t want to cross the way of the authority as the car is not registered yet.

100psi oil is pretty common when cold. It takes a while before mine drops and then normal driving it moves around quite a bit. Looks like Speedometer digital display got an upgrade, yours looks much nicer than mine.

Sounds great!

[edwardb]

RPM gauge remains at zero (4PPR mode, I will try the other modes), Oil pressure seems high but oil was cold and it’s a break-in oil (supplied by Fortes) with high viscosity I guess.

The correct Speedhut tach setting for the Coyote (Coil on Plug) is 0.5 PPR (Pulses Per Revolution). The coil on each individual cylinder only fires every other revolution. The Speedhut instructions show this plus how to set it.

The Coyote is well known for high oil pressure, especially at cold startup. I doubt you have an issue there.

Congratulations!

[Blitzboy54]

I've never seen anyone wait until the body was painted and installed before first start.

Really happy for your paint job it wasn't the pulse ring.

Congrats on what looks like a very nice build.

[sellig]

I've never seen anyone wait until the body was painted and installed before first start.

Really happy for your paint job it wasn't the pulse ring.

Congrats on what looks like a very nice build.

Thank you for your good words.
I have been waiting months for FFR to provide me a quote of new engineered Coyote Gen4 headers with catalytic converters and I ended up buying them to Gas-N who supplied them to me in 8 weeks. Received them 2 weeks ago and they fit perfectly.
Yes, I was worried about an unsuccessful start-up with the painted body on, but fortunately, it went well.

[sellig]

The correct Speedhut tach setting for the Coyote (Coil on Plug) is 0.5 PPR (Pulses Per Revolution). The coil on each individual cylinder only fires every other revolution. The Speedhut instructions show this plus how to set it.

The Coyote is well known for high oil pressure, especially at cold startup. I doubt you have an issue there.

Congratulations!

Ed, I tried unsuccessfully the 0,5PPR mode and neither all the others. The tach yellow wire is connected to the Coil-Tach purple wire from the dash gauge harness. Instructions talks about a resistor to connect to the yellow wire and +12volt power. Would you have any thoughts on this matter?

[edwardb]

Ed, I tried unsuccessfully the 0,5PPR mode and neither all the others. The tach yellow wire is connected to the Coil-Tach purple wire from the dash gauge harness. Instructions talks about a resistor to connect to the yellow wire and +12volt power. Would you have any thoughts on this matter?

Based on what you've described already, just want to confirm you have Speedhut (Vintage) gauges, right? If not, my answer does not apply. The 0.5 PPR setting is the only one that will provide an accurate tach reading for the Coyote assuming everything is wired correctly. Set the tach there and forget it. That's the right one. I assume you're following the Factory Five Coyote installation instructions?

https://www.factoryfive.com/wp-content/uploads/2025/06/Coyote-Gen-34-Fitment-roadster-rev-1K.pdf.

With Speedhut gauges and the Coyote it's necessary to break into the wiring on one of the coil packs for the tach signal as shown starting on page 107. Have you done this? With that wire connected back to the tach wire on the gauge the tach will function correctly when powered.

Not sure where you're seeing the reference to a resistor to connect to the yellow wire and +12volt power. Maybe in the Ford instructions? But that doesn't apply to Speedhut gauges.

Paul B. (EdwardB on the forum)

[sellig]

Based on what you've described already, just want to confirm you have Speedhut (Vintage) gauges, right? If not, my answer does not apply. The 0.5 PPR setting is the only one that will provide an accurate tach reading for the Coyote assuming everything is wired correctly. Set the tach there and forget it. That's the right one. I assume you're following the Factory Five Coyote installation instructions?

https://www.factoryfive.com/wp-content/uploads/2025/06/Coyote-Gen-34-Fitment-roadster-rev-1K.pdf.

With Speedhut gauges and the Coyote it's necessary to break into the wiring on one of the coil packs for the tach signal as shown starting on page 107. Have you done this? With that wire connected back to the tach wire on the gauge the tach will function correctly when powered.

Not sure where you're seeing the reference to a resistor to connect to the yellow wire and +12volt power. Maybe in the Ford instructions? But that doesn't apply to Speedhut gauges.

Paul B. (EdwardB on the forum)

Bonjour Paul,
The tachometer is working fine. As youi suggested, I connected it to the coil.
The speedometer has been received at Speedhut and they are going to modify it from GPS to Non-GPS (Cheaper than a new one).
One question regarding the speedometer sensor on the Tremec TKX gearbox : I have hard time to find the proper pigtail sensor connector. Already tried 4 connectors without success.
Would you have any recommendation about the model, type, part#?
217764217765

[edwardb]

Bonjour Paul,
The tachometer is working fine. As youi suggested, I connected it to the coil.
The speedometer has been received at Speedhut and they are going to modify it from GPS to Non-GPS (Cheaper than a new one).
One question regarding the speedometer sensor on the Tremec TKX gearbox : I have hard time to find the proper pigtail sensor connector. Already tried 4 connectors without success.
Would you have any recommendation about the model, type, part#?
217764217765

Glad the tach worked out. Kind of surprised you're switching away from GPS. I've done several builds with it and it's easy to hook up and doesn't need any calibration. But looks like your decision is done. Your Ron Francis harness should already have a connector that goes onto the TKX speed sensor. But if it doesn't, they're widely available. This is one example: https://www.hanlonmotorsports.com/product/hms-speedometer-pigtail-harness-ford-3550-tko-500-600-tkx-t56-magnum/. Good luck.

[sellig]

Thank you so much Paul for your responsiveness.
GPS tach is not allowed in the Province of Quebec claiming no connection in tunnels and underground parking lots.( when you know that there’s only 2 tunnels in the province . A weird!
I’m going to check locally with GM or Ford as shipping costs and tariffs are pretty high today.
Awaiting date confirmation for the mandatory mechanical inspection.
Thanks again and looking forward to reading your MK5 valuable comments. I’m a faithful follower of your projects.

[BRRT]

Mike Forte was able to provide the speedometer sender connector that I used for the Tremec TKX.