Coyote Gen3 rough idle at start then smooth

[toadster]

got a PO356 code back from Lund, I somehow missed this but it's an ignition coil circuit code for cylinder number 6. Of which is on bank 2

A vehicle’s PCM could log a P0356 code for a handful of reasons:


The (COP) could simply be faulty
Coil #6 could have a loose connection
Coil #6’s connector locks could be broken
The COP driver circuit is open
The COP driver circuit has a short to voltage or is ground

[Nigel Allen]

That plug insulator looks awfully carbonised. Swap your plugs to opposite banks and see if the fault follows.

Nige

[toadster]

That plug insulator looks awfully carbonised. Swap your plugs to opposite banks and see if the fault follows.

Nige

pulled Plug #1 from bank #1 looks dark like #6 but less oily for sure, we're checking the main grounds and swapping coil pack #6 and #1 to see if there's a bad coil

IMG_7812.jpg

[Nigel Allen]

Measuring resistance to look for bad grounds in vehicles is not easy and often leads to erroneous measurements which will take you down rabbit holes. A simpler and more solid way is to measure volt drop when a load is applied. Let's use the starter motor as the load.
With your meter set to DC volts, manual range. Apply one meter probe to your negative battery terminal and the other to your engine block. Observe meter reading whilst cranking, it should be less than 1volt. Any higher than that, and you have excessive resistance in your ground path.
Now repeat for positive path. Apply one meter probe to the positive battery terminal and other to starter positive terminal. Crank and measure volt drop on meter whilst cranking. Also should be less than a volt.
Make sure you measure to the terminals, that way you are also including the final connections in your measurements.

Let me know if you need further explanation or interpretation of measurement.

Best of Aussie luck to you. The quality of the coyote engine makes me feel that you will get there sooner than later.

As an aside, I found Lund a little blunt to deal with. Maybe the guy I dealt with was jaded, but I paid over a $1,000 Australian for a support guy that told me I was a wimp for not wanting to take car full load to 6500rpm. We had an unseasonably wet and cold winter and I was having traction issues at 60mph. I got there in the end using a dyno. Also he struggled with our fuel ratings here and in the end put what seems a very doughy tune in. It runs great otherwise. My takeaway is that Lund feel that they are the top dog. My advice is to keep the pressure on if they don't support you well.

Next time, I will use my local dyno. Those guys were great and super keen to help. Like I said, maybe I got the wrong guy, so hopefully your experience and others will be better.

Cheers,

Nige

PS: that spark plug looks bad enough not to fire on a cold engine.

[toadster]

swapped coils around, I cleaned the whole driver side bank of plugs - surprisingly serviceable (albeit no body on) - still getting the plug#6 misfire

Lund is suggesting maybe the harness is bad... I'd much rather replace a plug first, but I wouldn't think and engine running less than 15 minutes total would foul a plug - maybe just a bad plug out of the box?
we did replaced the power wire to the driver side to ensure the wire is the correct size, we had ~14ga wire in line and swapped out to 16ga which looks to match the rest in the loom.

does anyone have the pinout/schematic of the UEGO sensor wires? thinking maybe we have a bad solder joint in our extensions but would like to understand what each wire is first to tackle

[JeffP]

swapped coils around, I cleaned the whole driver side bank of plugs - surprisingly serviceable (albeit no body on) - still getting the plug#6 misfire

Lund is suggesting maybe the harness is bad... I'd much rather replace a plug first, but I wouldn't think and engine running less than 15 minutes total would foul a plug - maybe just a bad plug out of the box?
we did replaced the power wire to the driver side to ensure the wire is the correct size, we had ~14ga wire in line and swapped out to 16ga which looks to match the rest in the loom.

does anyone have the pinout/schematic of the UEGO sensor wires? thinking maybe we have a bad solder joint in our extensions but would like to understand what each wire is first to tackle

https://performanceparts.ford.com/do...-6017-M50B.PDF

Scroll to bottom and it has pinout for those connectors.

[Nigel Allen]

Change the plugs. A fouled plug on #6 might be causing the problem. The plugs look bad and may have been fouled excessively when running with exhaust sensing reversed.
Although my coyote is gen1, I found myself with rough running after multiple cold starts when testing. This was before and after Lund tune.

[Nigel Allen]

On the gen1 loom there is an inline fuse that feeds the exhaust sensors (heaters, maybe?) Not sure if that is case for yours... Might be worth following up.

Best of luck,

Nige

[JeffP]

Change the plugs. A fouled plug on #6 might be causing the problem. The plugs look bad and may have been fouled excessively when running with exhaust sensing reversed.
Although my coyote is gen1, I found myself with rough running after multiple cold starts when testing. This was before and after Lund tune.

I don't think he had his sensors reversed - I get to take credit for that one!

[toadster]

Change the plugs. A fouled plug on #6 might be causing the problem. The plugs look bad and may have been fouled excessively when running with exhaust sensing reversed.
Although my coyote is gen1, I found myself with rough running after multiple cold starts when testing. This was before and after Lund tune.

On the gen1 loom there is an inline fuse that feeds the exhaust sensors (heaters, maybe?) Not sure if that is case for yours... Might be worth following up.

Best of luck,

Nige

we checked all fuses, nothing was bad, but we did check - thank you

https://performanceparts.ford.com/do...-6017-M50B.PDF

Scroll to bottom and it has pinout for those connectors.

perfect - this will help with troubleshooting, the Bank2 (driver) O2 is pegged at 1.5, super rich, we're thinking it may be wire extensions so we'll redo these -
we swapped o2 sensors side to side, and the problem stayed on the driver side, I cleaned all 4 plugs on the driver side, wire brush and WD-40 (believe it or not) but they may be too cruddy...

the numbers on the right (below) came from Ford for the pinout of the ECU connectors

UEGO-driver-bank2.png

I don't think he had his sensors reversed - I get to take credit for that one!

yep! we even chatted with Ford Performance to verify the color of the wires per bank and we have the correct wires on the correct side as we had removed the labels marking the bank1 and bank2 sides - so we're good there

since the passenger side is so short, we shortened that run to not have the wires loop 1/2 way across the engine and come back - so it's a short extension to the O2 connector, the red wire was extended from the C146 plug over to the driver side, about 3.5-4 feet, and the other 4 lines were extended about 15 inches each.

we tested continuity and all 5 wires are fine, I'm wondering if the solder joints are creating resistance that is not reaching the ECU and thereby pegging the O2 sensor to flood the driver side with fuel

[edwardb]

...I'm wondering if the solder joints are creating resistance that is not reaching the ECU and thereby pegging the O2 sensor to flood the driver side with fuel

The Ford Performance directions say to not modify the O2 sensor harnesses. But with the standard lengths delivered on both Gen 2 and Gen 2, you are left with either modifying them or adding purchased extensions. I've cut and soldered the O2 harness wires on both of my Coyote builds with no issues whatsoever. Note I said harness and not the wires in the pigtail between the sensor and the plug. That has special insulation and wire that isn't friendly to work with (ask me how I know) and should be left alone. As long as you have good connections on the splices you did there shouldn't be an issue. It's just standard hook-up wire and the small amount of solder shouldn't matter. It hasn't for me.

I agree with the post Jeff Kleiner made earlier. It's likely your O2 sensors are reacting to another problem. As opposed to them being the problem itself. Especially since you aren't getting specific O2 sensor DTC's. They could fail completely or even be removed and the engine should still run on all cylinders. Albeit poorly and maybe even go into limp mode. Same with fouled plugs. The Coyote (like all modern engines) has a hot ignition system that can fire through most plug situations. The maintenance cycle on them is 100K miles. Again, the fouled plug(s) IMO is a symptom of another issue but not the issue itself.

Something else is wrong IMO. Has Ford Performance suggested the possibility of re-flashing your PCM? More than one problem has been solved by that step. That used to be a pretty standard go-to when everything else seemed OK. Has happened to me once. It would wipe out your Lund tune. But just re-load it again.

[JeffP]

Agree with Paul and Jeff on this one that the o2 is more of a symptom. Given I had mine reversed for 1000mi and (at least after initial startup) the car ran perfectly.

[toadster]

The Ford Performance directions say to not modify the O2 sensor harnesses. But with the standard lengths delivered on both Gen 2 and Gen 2, you are left with either modifying them or adding purchased extensions. I've cut and soldered the O2 harness wires on both of my Coyote builds with no issues whatsoever. Note I said harness and not the wires in the pigtail between the sensor and the plug. That has special insulation and wire that isn't friendly to work with (ask me how I know) and should be left alone. As long as you have good connections on the splices you did there shouldn't be an issue. It's just standard hook-up wire and the small amount of solder shouldn't matter. It hasn't for me.

I agree with the post Jeff Kleiner made earlier. It's likely your O2 sensors are reacting to another problem. As opposed to them being the problem itself. Especially since you aren't getting specific O2 sensor DTC's. They could fail completely or even be removed and the engine should still run on all cylinders. Albeit poorly and maybe even go into limp mode. Same with fouled plugs. The Coyote (like all modern engines) has a hot ignition system that can fire through most plug situations. The maintenance cycle on them is 100K miles. Again, the fouled plug(s) IMO is a symptom of another issue but not the issue itself.

Something else is wrong IMO. Has Ford Performance suggested the possibility of re-flashing your PCM? More than one problem has been solved by that step. That used to be a pretty standard go-to when everything else seemed OK. Has happened to me once. It would wipe out your Lund tune. But just re-load it again.

Agree with Paul and Jeff on this one that the o2 is more of a symptom. Given I had mine reversed for 1000mi and (at least after initial startup) the car ran perfectly.

agreed, since we have continuity in wires and driver side is always pegged rich, I'm talking to Ford to get the PCM reflashed

ordered 8 new plugs as well, relatively cheap in the grand scheme of things... Ford was pretty stumped as to why Bank2 wouldn't fire properly

the only things I've found online in regard to this issue is a plugged catalytic converter, of which I have them in the headers, but we're feeling airflow, just not hot like the passenger side
knowing my luck somehow JetHot melted or damaged the media when coating these headers (and/or) the rich fuel mixture could have done it as well...

pretty frustrating as we've never even run this engine hot enough to get the fans to kick in - we've only achieved about 126F on the coyote temp meter

thanks all for your inputs, what seemed to be a simple crate motor setup has become quite frustrating...

[Railroad]

Would a noid light help in seeing what is doing what?

[toadster]

Would a noid light help in seeing what is doing what?

I rented one yesterday, haven't had a chance to test it yet

[Nigel Allen]

What happens if you unplug the driver side sensor, then start the engine?
Could it be that because the sensor is reading rich, that fuel is not being injected on that bank?

Apologies if you have already tried this.

Cheers, Nige

[toadster]

What happens if you unplug the driver side sensor, then start the engine?
Could it be that because the sensor is reading rich, that fuel is not being injected on that bank?

Apologies if you have already tried this.

Cheers, Nige

just tried this - unplugged the O2 sensor on the driver side, same symptoms as with it plugged in
even swapped the #6 and #1 plugs to see if it was a fouled plug, same issues...

I tried the noid lights but couldnt' get any of the adapters to fit the coyote plug wire feeds, may try rigging up some aligator clips and pins to try to hook them up but none were a direct fit

[Railroad]

They make a hand held noid light. It looks like a screw driver with a paddle on the end. You can hold it near the wire or device you are checking. No connecting or disconnecting.

[toadster]

They make a hand held noid light. It looks like a screw driver with a paddle on the end. You can hold it near the wire or device you are checking. No connecting or disconnecting.

I'll have to check those out, found them in some searches too - not too pricey...
something dawned on me last night

I removed my CMCVs from the back of the Coyote, and there are 3 connectors inline on the way to bank 2 behind the back of the engine
I have a query out to Ford on this as well, but do these connections help to ground Bank 2?

cmcv-removal.png Screenshot 2023-05-04 072929.png

if I created a ground gap, then it would affect all spark on the driver side... of course, I think I tossed the whole setup so I'd need a new solenoid ~$25

[toadster]

spent the better part of today testing continuity and resistance on about 40 ECU wires - the harness looks to be working, tested connectivity to each coil pack and ground, and each injector and ground

can't test the coil packs - the online stuff I've seen is for all older 4.6/5.4 engines

I have one of the flyswatter noid lights coming tomorrow to verify spark activity -most likely will ship the ECU in monday to ford

[Indy Shu]

If you want to check a coil, just pull it out and put a spare spark plug in it. Start the engine and see if it is firing. Takes about 30 seconds. I found I had a dead coil this way. Ford sent me a replacement.

[Jeff Kleiner]

Todd,
Noid light will only tell you that you’re sending an electrical signal to a coil but won’t tell you that it’s actually working. Do what John said above and you’ll have your answer.

Jeff

[toadster]

If you want to check a coil, just pull it out and put a spare spark plug in it. Start the engine and see if it is firing. Takes about 30 seconds. I found I had a dead coil this way. Ford sent me a replacement.

yep going to do this today as well

i'm getting pretty good with this 8mm socket (haha)

[toadster]

tested the noid light, all COP firing, cylinder #4 seemed to be double speed firing
also tested each coil with an arc test, all 8 are producing spark as well - shipped off the ECU, nothing else that we can possibly do

[toadster]

got the ECU back from Ford.. slightly different response

from LUND
"It's still showing the same problem. Ignition coil F circuit, and AFR on bank 2 still max lean.
What's really weird though is the fuel trim for that bank isn't reflecting the issue.
The trim looks fine. If it was really that lean as AFR is showing I'd expect the fuel trim to be trending in a fashion to correct for it."

my confusion:

• we tested all 8 coils, moved them between cylinders, also move sparkplugs between cylinders - but Ignition coil F circuit is still not working properly (this is cylinder #6)
• we also swapped O2 sensors side to side, and the problem is lambda is still pegged on bank2 which I believe may be a wiring issue? although we tested continuity and resistance

Here's the info from my log (HP Tuners OBD2), this is on the stock ECU code that was re-programmed, nothing else modified
The P2008, P2017, P2022 are all expected as I removed the IMRC valves from the rear of the intake (the tuner can remove those issues)
P0365 is the one that keeps showing up which is cylinder #6
I don't remember seeing P0124 before, but is shown in this log this is a generic OBD-II code that indicates the TPS sensor circuit A output voltage goes below or above the sensor's expected range

Protocol Info: J1962: CAN, 500 kb/s

ECM: 7E8, CAN, ECM -EngineControl - TC-298, 2018+ Ford
VIN: ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
User OS: FRPP9
Calibration IDs: ÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃÃ
Calibration VNs: 79FD439B
Basic PIDs: 44
Trouble Codes:
P2008 - Intake Manifold Runner Control Circuit/Open Bank 1 (Pending)
P2017 - Intake Manifold Runner Position Sensor/Switch Circuit High Bank 1 (Pending)
P2022 - Intake Manifold Runner Position Sensor/Switch Circuit High Bank 2 (Pending)
P0356 - Ignition Coil F Primary/Secondary Circuit (Permanent)
P0124 - Throttle/Pedal Position Sensor A Intermittent (Permanent)
Controller Type ID By User OS: 12018


a bit stumped...


any ideas?

Ford is escalating to engineering...

[edwardb]

P0124 in my experience with a new engine is a false positive. Which could be the same in your case with a newly flashed ECU. Clear it and I bet it doesn't come back. After all you've been through and still the problem isn't isolated, my vote is something wrong with your harness. Another builder on here had issues he couldn't resolve with a Gen 2. After exhausting all the options, Ford Performance supplied a new harness and all good. Obviously a pain to tear out the old and replace, but that's my guess. Hopefully Ford is standing behind this because clearly it's not working as it's supposed to and seemingly there are no user errors. I feel for you. Took my Gen 3 powered Coupe for a 50 mile cruise today. Runs so perfect. Hang in there. Yours will be like that.

[toadster]

P0124 in my experience with a new engine is a false positive. Which could be the same in your case with a newly flashed ECU. Clear it and I bet it doesn't come back. After all you've been through and still the problem isn't isolated, my vote is something wrong with your harness. Another builder on here had issues he couldn't resolve with a Gen 2. After exhausting all the options, Ford Performance supplied a new harness and all good. Obviously a pain to tear out the old and replace, but that's my guess. Hopefully Ford is standing behind this because clearly it's not working as it's supposed to and seemingly there are no user errors. I feel for you. Took my Gen 3 powered Coupe for a 50 mile cruise today. Runs so perfect. Hang in there. Yours will be like that.

thanks Paul - this build has been a challenge for sure, but we thought the crate motor would have been 'plug-and-play' like many others, but this gremlin sure has tested our patience...
when Ford says - I've never heard of this, that's not reassuring...

we keep pluggin away...

[JeffP]

thanks Paul - this build has been a challenge for sure, but we thought the crate motor would have been 'plug-and-play' like many others, but this gremlin sure has tested our patience...
when Ford says - I've never heard of this, that's not reassuring...

we keep pluggin away...

Any update? Curious on the outcome of this.

[toadster]

Ford was out Friday and today for the holiday, will calll again tomorrow…

[toadster]

the main guy "Ken" at FP wasn't available today, the other tech I talked with said that extending the O2 harness would most likely screw up the O2 readings...

I did do a test over the weekend and moved the O2 harness from bank2 over to bank1 (obviously the bank1 leg is too short to extend to bank2 so I ran bank 2 open)
Lund confirmed that the problem followed the harness, O2 shows pegged lean on bank1 when I move the harness over

not sure if we did something different, but we soldered in similar sized wire when we extended the harness - about 16 inches per wire, the red wire has a full run from the split in the harness all the way to the sensor.

I believe I may need another CM-14A006-MTRANS harness which is the O2 extension 90-pin plug, waiting to hear back from Ford

I can't find this by itself on Ford Performance's catalog, so may be a special order
Attachment 185203

at this point I may get a new CM-14A006-MTRANS harness and buy some extenders instead of soldering, there's no way the stock harness can reach both ends of the O2 plugs in this setup
if someone has been able to get the wires to reach without extending, I'm all ears...

[JohnK]

Hey Todd - so sorry to hear that this has been such a hassle for you. Just thought I'd share my experience in case it's helpful for you. On my first set of headers I was able to connect both O2 sensors without extending the harness (barely), but when I switched to the Gas-N headers the PS was just barely too short. Gas-N provide 12" extenders with the headers, so I used one on the PS side and it works perfectly. Hopefully using the extender vs. the soldered extension solves your problem.

[edwardb]

the main guy "Ken" at FP wasn't available today, the other tech I talked with said that extending the O2 harness would most likely screw up the O2 readings...

I did do a test over the weekend and moved the O2 harness from bank2 over to bank1 (obviously the bank1 leg is too short to extend to bank2 so I ran bank 2 open)
Lund confirmed that the problem followed the harness, O2 shows pegged lean on bank1 when I move the harness over

not sure if we did something different, but we soldered in similar sized wire when we extended the harness - about 16 inches per wire, the red wire has a full run from the split in the harness all the way to the sensor.

I believe I may need another CM-14A006-MTRANS harness which is the O2 extension 90-pin plug, waiting to hear back from Ford

I can't find this by itself on Ford Performance's catalog, so may be a special order
Attachment 185203

at this point I may get a new CM-14A006-MTRANS harness and buy some extenders instead of soldering, there's no way the stock harness can reach both ends of the O2 plugs in this setup
if someone has been able to get the wires to reach without extending, I'm all ears...

A bunch of us, me included, have shortened and lengthened the O2 harness wires with zero issues. I've done it on both the Gen 2 and Gen 3. I know the Ford instructions say not to. But it's plain old automotive hook-up wire up the the O2 sensor plugs. I have no idea why a properly spliced wire (several ways to do it) would be a problem. But apparently you found out. Factory made extensions are another option and some go that way. Casper's Electronics is a source I've seen mentioned. Based on a quick search, BBK is another with a number of choices. Looks like you'll have to start with a new harness leg though if testing confirms the one(s) you have can duplicate the problem.

[toadster]

Ford got back to me and is talking with their electrical team to see if they can get me a new pigtail for the O2 sensors
it's a waiting game at this point, the tech lead won't be back until at least 6/5

[toadster]

well, I was travelling all week - Ford dropped a new O2 harness in the mail, should be here next Thursday... oh the waiting!

I also picked up a 24" O2 extension from Lethal Performance which may remove the need to solder any extensions

[toadster]

got the new o2 harness today from Ford, only peeled back the tape enough to get the o2 wires to reach, i added a 24" o2 extender which helped with the width - still will have to modify the red wires somehow to clean up the wiring it's just way too short side to side

same issue, pegged lean on the driver side

we even swapped cables side to side and the problem still exists on the driver side bank

literally driving me crazy at this point

1. ECU was reflashed by ford
2. new o2 pigtail didn't resolve the issue

any coyote gurus with ideas?

taking the car to the painter tomorrow to get the rough in done, and I'll have some time to wait on paint but need to get this resolved!

[Nigel Allen]

Measure the O2 sensor heater wires to verify voltage at the heater elements.

[Alan_C]

Good call. I had this happen on my build where a pin in one of the O2 extender connectors was not seated and pushed back to where contact for the heater circuit was not working. So one bank was not running properly and fortunately the shop I took the car to diagnosed the issue in about an hour. I had replaced that O2 sensor twice before figuring out the issue.

[Nigel Allen]

Flashing the ECU will not fix a hardware issue, if there is one within the ECU. Hopefully they operationally tested the ECU to prove all circuits operate correctly. It could be that the ECU has a pre existing hardware fault.

Is there anyone nearby that you can swap an ECU with to test?

Sorry to see you having so much pain with this issue.

Wishing you the best of luck,

Nige

[toadster]

no clue if they tested functionality of the ECU, you'd think that would be standard procedure, but I'm assuming...

Lund is recommending trying a new o2 sensor, so $80 later and waiting for it to arrive- although the car is at the painter getting pre-fit prior to paint - so I have a week or so to wait...

no nearby ECUs that aren't already mounted - would be a PITA to pull one just for testing

[toadster]

just to give an update on this

I got a new O2 sensor, but doubtful that it will be useful - may just return it

the PO365 code it lends itself to a circuit issue, so Ford gave me some more testing to do; it's pretty rigorous but it's testing for voltage and resistance at the coil connector to the ECU pinout
essentially finding a short either in the engine harness, the control pack harness, or the ECU - definitely not in the usual installation manual

hopefully i'll get up to Ken's and can do some testing to get parts shipped out when I get the chassis back...