Gen 3 Coyote Hard Start Issues - Don't' think its wiring related.

[Barwickad]

Looking or any suggestions or troubleshooting tips to solve a hard start condition when cold and no-restart condition when hot. I have a new Gen3 Coyote and Control Pack, shipped in August of last year. Did my first start a few days ago. The engine cranks and periodically chugs until it catches after 15-20 seconds. When its cold it usually starts after the extended cranking but it will not re-start after reaching normal operating temperature. It needs to sit overnight and completely cool before it will start again. Once the engine is running it seems to operate perfectly. Sounds great, idles smoothly and revs as expected. Oil pressure, water and oil temps are as expected. The PCM driven fan cycles on at 195 ish. The PCM is not setting any DTC's but my MIL light does not come on at all. (I’ve been chasing the hard start issue first.) I have the FF Coyote install kit and CAI. The MAF is oriented correctly, I've checked twice. I have the same fuel pump setup (Pro M hanger) and Aeromotive regulator set to 65PSi that has been used on many gen 3 builds successfully. I believe everything is installed per the FF Coyote and the Ford Performance Control Pack instructions and I've checked all my grounds for continuity. I have the Digital Guard Dog PBS 1 installed and working correctly. One push to energize the ACC circuit and a second to start. The fuel pump primes for a couple seconds when the ACC circuit is energized and fuel pressure comes up to spec almost instantly, barely a second. I even put the Ford provided air box on upside down to see it made a difference, nope. If I pull a plug after an extended crank and no start the plugs do look a little wet.

I reached out to Ford Performance and after a brief description of my problem the tech told me I could expect the "gen 3 to crank for up to 60 seconds". When I politely questioned 60 seconds and mentioned other folks with identical builds were not seeing such an extend crank time he bluntly asked why I was challenging his technical expertise. It was a pretty short call after that.

Any help or suggestions or trouble shooting steps would be very much appreciated.

[michael everson]

The only thing that comes to mind for me is the ignition switch. Any chance you have the orange wire and brown wire reversed? I other words the ign and Acc are swapped?
Mike

[Jeff Kleiner]

...the tech told me I could expect the "gen 3 to crank for up to 60 seconds".

Well that's just ridiculous!

Jeff

[Barwickad]

Well that's just ridiculous!

Jeff

Ain’t that the truth!

“ Any chance you have the orange wire and brown wire reversed? I other words the ign and Acc are swapped”

Thanks for the ideas, Mike. Your suggestion made me go back and go through all the critical wiring connections again. I didn’t find anything out of place and all the checks seem to make sense and match the FF and Ford instructions.

I did notice one oversight. I don’t have the vacuum line hooked up to the FPR as Ford recommends. I know some guys have left that off at Lunds direction. I’ll probably hook that up tomorrow just for grins.

Any comments on the extended cranking sessions doing any harm? Cold starts are usually <20 seconds before it fires up. I am certainly hesitant to go any longer than that for fear of doing damage somewhere.

[edwardb]

Can't add anything to what's already been posted. Based on what you've described, sounds like it's wired correctly. It wouldn't start or run if it wasn't. The vacuum reference line on the regulator isn't going to change the behavior you're experiencing. I've played around with that on both Gen 2 and Gen 3 Coyotes and with everything stock haven't seen any difference. For a stock setup (e.g. normally aspirated) I've left if off per Lund's recommendation. What are your plans regarding a custom tune? It's well established that (1) the Gen 3 basically requires it, and (2) the stock tune (aka calibration) from Ford Performance is extremally rich. More than the fuel trims can adjust for. The fact you're seeing wet plugs is maybe a clue? But take this what it's worth. A slightly educated guess. Even as bad as the stock tune is, it should start and run more easily than you're experiencing.

[Barwickad]

Can't add anything to what's already been posted. Based on what you've described, sounds like it's wired correctly. It wouldn't start or run if it wasn't. The vacuum reference line on the regulator isn't going to change the behavior you're experiencing. I've played around with that on both Gen 2 and Gen 3 Coyotes and with everything stock haven't seen any difference. For a stock setup (e.g. normally aspirated) I've left if off per Lund's recommendation. What are your plans regarding a custom tune? It's well established that (1) the Gen 3 basically requires it, and (2) the stock tune (aka calibration) from Ford Performance is extremally rich. More than the fuel trims can adjust for. The fact you're seeing wet plugs is maybe a clue? But take this what it's worth. A slightly educated guess. Even as bad as the stock tune is, it should start and run more easily than you're experiencing.

I have a dyno tune scheduled in a few weeks with a local tuner. Hopefully he can work the kinks out.

I did hear back from Ford Performance (not the 60 second guy). They didn’t have allot to offer as far as specifically what may be off, but they did say “with a certainty a custom calibration for the CAI would fix the issue”.

I plan to get as many miles as I can go-karting around my neighborhood before the dyno appointment. I’ll follow up after the dyno appointment. Hopefully good news.

Thanks for all the feedback.

[Sharris2]

Check fuel pressure before, after and during running? You maybe loosing fuel pressure when shut down for a period of time (the 60 seconds) hence the long cranking.

Scott

[Barwickad]

Check fuel pressure before, after and during running? You maybe loosing fuel pressure when shut down for a period of time (the 60 seconds) hence the long cranking.

Scott

Hi Scott. I’ve been watching the fuel pressure carefully throughout this ordeal. As I suspect my issue is fuel related in some way. As soon as the ignition is powered on (before cranking) the pressure comes up to spec (65 psi) in under a second and remains solid during cranking and once the engine is running. As soon as the engine is shut off the pressure drops to zero over a minute or so. I believe this is normal behavior for the Aeromotive return style FPR that I have.

[JeffP]

This may be a long shot and doens't specifically fit your symptoms - but make sure you don't have your O2 sensors reversed like I did. Its easy to do when you're adjusting harness length on a workbench to get your left/right reversed in your head I can tell you my Gen3 starts consistently on the 2-3 crank hot or cold without fail.

[Indy Shu]

Hi Scott. I’ve been watching the fuel pressure carefully throughout this ordeal. As I suspect my issue is fuel related in some way. As soon as the ignition is powered on (before cranking) the pressure comes up to spec (65 psi) in under a second and remains solid during cranking and once the engine is running. As soon as the engine is shut off the pressure drops to zero over a minute or so. I believe this is normal behavior for the Aeromotive return style FPR that I have.

I have the same fuel system and it holds pressure for quite some time. Even after sitting for a long period and down to no pressure, the pump builds pressure like yours and fires right up, no long crank.

[Rsnake]

My gen3 was also slow to start as the aeromotive pressure regulator would bleed off pressure immediately after Turing off engine. I installed a tanks brand from summit and it holds pressure for days and the engine fires up immediately.
Not sure what's the issue with the aeromotive but I will never use another.

[Alan_C]

My gen3 was also slow to start as the aeromotive pressure regulator would bleed off pressure immediately after Turing off engine. I installed a tanks brand from summit and it holds pressure for days and the engine fires up immediately.
Not sure what's the issue with the aeromotive but I will never use another.

Did you contact Aeromotive to determine if their FPA works that way or if it was faulty? A lot of people here use the Aeromotive FPA, if they did not work, everyone would switch to another brand.

[Rsnake]

I did contact aeromotive and they said its normal for the pressure to bleed off and nothing they could do.
With the aeromotive as soon as you turn the key off the pressure drops to zero in a matter of seconds.
The tanks brand holds pressure for days if not weeks. It will drop 20-30 psi in a few hours but then hold 20-30 psi for many days and sometimes weeks. I just drove it today and 4 hours after returning it's still at 35 psi.

[Sharris2]

I have the same aeromotive regulator it's hold pressure for a few days; drops very gradually

[Barwickad]

Curious if anyone know’s. Does the stock Gen3 Mustang fuel system maintain fuel pressure long after the engine is shut off?

JeffP. Thanks for the suggestion. I checked my O2 sensor wires this afternoon to make sure I had not swapped the harness’s between Bank1 and Bank2. Nope, they are correct. I did lengthen the drivers side O2 harness by splicing in new wires. (Hindsight: I would have bought a pre-made extension.). But I am not seeing any DTC’s at all, let alone O2 sensor related. When I review the live stream data with the engine running the O2 sensor values are nearly identical across the operating temperature and RPM range on both B1 and B2. So I don’t think it’s an O2 hareness issue.

[michael everson]

I doubt it’s fuel pressure regulator related. Even at zero pressure it only takes a couple seconds to pressurize. Wonder if you have a faulty crank sensor.
Mike

[edwardb]

Curious if anyone knows. Does the stock Gen3 Mustang fuel system maintain fuel pressure long after the engine is shut off?

The Mustang uses a variable computer controlled returnless fuel pump. Totally different setup than crate motor control pack. I don't know for sure, but doubt any comparisons are meaningful. FWIW, I've used Aeromotive regulators in three builds with zero issues. So I don't share the concern with them. However long they, or the overall fuel system, takes to bleed down is a non-issue in my experience. Even after my cars sit all winter for multiple months they start after just a few cranks. With a gauge on the regulator, can see the fuel system pressurizes almost immediately. With a brand new installation, and zero fuel in the lines, rails, etc., I can see where the engine might crank more than normal. But after that, at least in my experience, starting is usually just a couple seconds of the starter motor. Just had the Gen 3 Coyote powered Coupe out for two cruises yesterday. Started immediately after sitting for about 5 days. As I stated earlier, it does seem that Ford made a calibration change for later control packs that doesn't initially briefly run the fuel pump. Which might slightly lengthen the time the engine cranks. But still shouldn't crank for some of the times mentioned here. I agree likely something else is happening other than the fuel system. You mentioned a custom tune and will be very interested to hear if that changes anything.

[FFinisher]

I would make sure the fuel pump is energized in the start position.

Seems like you have done everything, you are using the control pack fuel pump wiring. Thats not normally a problem.

Try jumping the fuel pump to run continuously while trying to start. See what happens.

You have stated it runs in the ACC/Run position, wondering if it is cutting out in the start position, you catch it sometimes release the key and it catches. Other times not.

That's all I got.

[Jryasko]

The long crank on First Initial Start is pretty normal. A lot of plumbing till fill up and get bled, and with the Ford control pack fuel pump only runs a couple seconds until it sees engine running. After that agree with the other Gen 3 owners, even after sitting minimal cranking and instant starts. Being your seeing wet plugs, it is almost like an issue with a sensor or the Control Pack itself, and not a fuel issue. I do have the same regulator and it will hold the pressure for a week. But if you crank and get instant pressure it shouldn't be an issue. Would really be interesting if someone close had the same control pack and you could try it. Do you recall anything funny when you put the flywheel on with that rear crank sensor ? Might check all your sensor plugs to make sure a pin isn't backed up and they are all seated correctly. I assuming side pipes and O2 sensors are installed. No side pipes and O2 sensors are going crazy. 1 other thing when you go to dyno, many have used the Lund Tune, which works fine. I didn't really like the idea of WOT on a car I'm not familiar with to Data Log. I ended up using an HP Tune on the Dyno. An SCT Tuner will Not Talk to the crate engine. If by chance you need the code for HP to access the ECM let me know I can send it to you. Good luck and keep us updated on here what you find. JY

[Barwickad]

Interesting comments on the crank sensor, thanks Jryasko. I received my engine and transmission fully assembled, so I can’t comment on any issues with the crank sensor during assembly. I will certainly do some checking on the car when I get home. I did some research on the crank sensor and came across this video suggesting that anytime the flywheel (or flexplate) is disturbed on a Coyote you should perform a crank re-learn to avoid potential issues.

https://youtu.be/XELjn3z3GgE

Obviously this hasn’t been done on my setup. I’ll need to check to see if my DTC tool is capable of this. (Pretty sure. It’s not.). If not I’ll bring it up to the tuner. Scheduled for the dyno on Aug 1st

Curious. I haven’t heard anyone mention doing this with any of the gen3 builds or tunes on this forum.

[Barwickad]

Thought I’d follow up on my hard start issues, in case someone else has similar problems down the road.

We put the car on the dyno last week and within a few minutes the tech identified the high pressure (direct injection) fuel rail sensor wasn’t talking. (The sensor voltage was flatlined at 5v and didn’t change with rpm.) We checked the sensor and found the electrical connection, had been crushed and I presume shorted. No idea how it got damaged as the sensor is up underneath the DS IMRC canister. Anyway. A new sensor and pigtail and she runs and starts like she’s supposed to.

[kirby]

Glad you solved it. I had been watching this thread closely as I get close to my first start.