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Gen 3 Aluminator Coyote First Start!
Huge milestone with the first start! Thank you to everyone who has helped answer my questions along the way!
http://youtube.com/shorts/0_gkf0THG2...HAwmFTqthPMZkN
After running, fuel started coming out of the vacuum line:

Would this indicate an internal issue with the fuel regulator?
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Post Thanks / Like - 0 Thanks, 2 Likes
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I'm going to go out on a limb and say yes. That's a problem. I've typically left the vacuum reference line open to atmosphere based on the recommendation of Lund Racing for an NA setup. Haven't ever seen fuel come out of them on multiple installations. All Aeromotive 13129 regulators.
Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
Build 2: Mk4 Roadster #7750. Sold 04/10/2017.
Build 3: Mk4 Roadster 20th Anniversary #8674. Sold 09/07/2020.
Build Thread and
Video.
Build 4: Gen 3 Type 65 Coupe #59. Gen 3 Coyote. Legal 03/04/2020.
Build Thread.
Build 5: 35 Hot Rod Truck #138.
Build Thread. Sold 11/9/2023.
Build 6: Mk5 Roadster 30th Anniversary #11,258.
Build Thread.
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Yes, that is a problem. And a fire hazard.
Once that is fixed and fuel pressure is set be sure and remove the gauge, they have a nasty habit of springing leaks.
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Originally Posted by
Mike.Bray
Yes, that is a problem. And a fire hazard.
Once that is fixed and fuel pressure is set be sure and remove the gauge, they have a nasty habit of springing leaks.
Will do! My wife was adjusting the fuel pressure and then it started leaking. Will dial it back a bit, but just ordered another regulator (Aeromotive 13129) and test it out again.
If it still leaks, I will look into the return line by unhooking from the ss lines to the fuel tank and into a 5gal. bucket.
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Quick update and question for other's that have experience with Coyote motors (specifically gen 3).
Replaced the fuel pressure regulator with aeromotive 13129. No more leaks.
Now the next question is about the long crank/start for the Gen 3 coyote. Is this normal?
Takes 5-10 seconds to start and sometimes even longer. I noticed the aeromotive fuel pressure regulator loses pressure (back to 0psi) as soon as I turn the engine off.
Does the fuel pump prime when the key is in the 'start' position?
Find it kind of odd that the fuel pressure regulator is not holding fuel pressure.
Also looking for a tuner so any recommendations would be great. Can a tuner adjust parameters in the ECU to prime the engine when the key is in the 'On' position?
Wondering if I wired something wrong here.
This is what I have done so far:
Ground strap from engine block to frame
Ground strap from starter bolt to frame
Checked battery (purchased last summer and has been sitting in garage) and it stays at around 12 -13v and drops to about 9.5v when cranking
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Responses:
Many have reported the Gen 3 takes some cranking for the first start during the build. But once it's been started and has fuel throughout (I'm assuming that's the reason) it starts relatively quickly. Certainly not 5-10 seconds. May Gen 3 powered Coupe started in just a couple seconds after sitting all winter. I've not looked at the pressure gauge to see how quickly it bleeds off after starting. I typically remove the gauge after several months after everything is checked out and stabilized.
Yes, the fuel pump runs very briefly when you first turn the key. Typically you can hear it. But it's quick and doesn't start running again until the engine starts. My experience, as noted above, is this is enough to allow a relatively quick start.
I've used Lund Racing for my Coyote tuning. Many others have as well. Not cheap. If you have a local source that knows your engine it might be cheaper. I'm not aware of tuning parameters that can be changed as you described. But then again, I'm not all that familiar with many aspects of what's in the tune. Based on my experience though, it's not something that should be necessary.
Your battery should show a higher surface voltage and especially a higher voltage when cranking. I'd recommend getting it tested. That's not helping your start situation and it could fail at some point if it's not charging properly.
Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
Build 2: Mk4 Roadster #7750. Sold 04/10/2017.
Build 3: Mk4 Roadster 20th Anniversary #8674. Sold 09/07/2020.
Build Thread and
Video.
Build 4: Gen 3 Type 65 Coupe #59. Gen 3 Coyote. Legal 03/04/2020.
Build Thread.
Build 5: 35 Hot Rod Truck #138.
Build Thread. Sold 11/9/2023.
Build 6: Mk5 Roadster 30th Anniversary #11,258.
Build Thread.
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Relating to Paul's post above...if your battery checks out, then make sure that you rev the engine a little to get the alternator's excitation voltage above the self-energizing threshold. Then you should have decent running voltage (assuming no other electrical issues are present) 
Craig C
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Originally Posted by
cc2Arider
Relating to Paul's post above...if your battery checks out, then make sure that you rev the engine a little to get the alternator's excitation voltage above the self-energizing threshold. Then you should have decent running voltage (assuming no other electrical issues are present)
Craig C
That's not necessary with a 3g or newer alternator, that's an older 1 wire alternator issue.
I would think you have a battery issue if it's falling below 12v when cranking, and making starting harder
Last edited by rich grsc; 04-07-2026 at 08:43 AM.
Mrk III, 331 stroker, Borla stack injection, T5, 3:55 IRS, Power steering and brakes. Kleiner body & paint
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In regards to the aeromotive regulator losing pressure, I had the same issue on two builds and purchased a different brand. Starts immediately and holds pressure.
I am not a fan of Aeromotive after two units with two issues.
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Originally Posted by
edwardb
Responses:
Many have reported the Gen 3 takes some cranking for the first start during the build. But once it's been started and has fuel throughout (I'm assuming that's the reason) it starts relatively quickly. Certainly not 5-10 seconds. May Gen 3 powered Coupe started in just a couple seconds after sitting all winter. I've not looked at the pressure gauge to see how quickly it bleeds off after starting. I typically remove the gauge after several months after everything is checked out and stabilized.
Yes, the fuel pump runs very briefly when you first turn the key. Typically you can hear it. But it's quick and doesn't start running again until the engine starts. My experience, as noted above, is this is enough to allow a relatively quick start.
I've used Lund Racing for my Coyote tuning. Many others have as well. Not cheap. If you have a local source that knows your engine it might be cheaper. I'm not aware of tuning parameters that can be changed as you described. But then again, I'm not all that familiar with many aspects of what's in the tune. Based on my experience though, it's not something that should be necessary.
Your battery should show a higher surface voltage and especially a higher voltage when cranking. I'd recommend getting it tested. That's not helping your start situation and it could fail at some point if it's not charging properly.
Here’s a quick video my wife took of a start (please note this is starting the engine about 3 minutes after a cold start): https://youtube.com/shorts/p8PNug4rP...hhCcr1UOFPfR_B

Originally Posted by
Rsnake
In regards to the aeromotive regulator losing pressure, I had the same issue on two builds and purchased a different brand. Starts immediately and holds pressure.
I am not a fan of Aeromotive after two units with two issues.
Which fuel pressure regulator did you end up going with?
I’m wondering if there are issues with the direct injection or injectors leaking.
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Originally Posted by
Rsnake
In regards to the aeromotive regulator losing pressure, I had the same issue on two builds and purchased a different brand. Starts immediately and holds pressure.
I am not a fan of Aeromotive after two units with two issues.
Never had an issue with any Aeromotive units I've had. Pretty popular hardware on the site. You should have bought a lottery ticket.
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Congrats on first start! Nothing like the noisy,first breath of life from your collection of parts to motivate you to finish the build!
I've used a number of different brand of aftermarket FPR's (Aeromotive, Mallory, Holley, Summit) over the years and none would reliably hold pressure after shutting the engine off like an OEM FPR could. Most will bleed pressure off in a few minutes, wheres the OEM unit would still be solid after days parked in the garage. I've been running the same Mallory FPR for more than 15 years now. It still bleeds off pressure relatively quickly, but never fails to start and run reliably.
as mentioned earlier, I'd get rid of the FPR mounted pressure gauge. replace it with a Schrader valve like this:
https://www.summitracing.com/parts/ear-9616sverl
Then you can use a portable. diagnostic FP gauge when you need to confirm pressure.
Sean
MK 3.5 roadster (MK IV body retrofit to MK III chassis) 396W stroker, Edelbrock Pro-Flo 4, AFR 195CC Renegade, XE274HR, GP 4-1-4 SS headers, 3link, 3.73, 15" Halibrand replicas, SAI mod, bumpers, 2 X roll bars, IČ electronics, PS, hydroboosted brakes: 95 GT front, custom MK VIII calipers/Cobra discs rear, FFR front, Levy rear LCA's, Forte front, VPM rear bars, CF dash, mod comp layout w/Auto Meter Ultra-Lites, Lucas tri-bar headlights, coupe taillights, painted by SRP (again!)
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Originally Posted by
canuck1
Congrats on first start! Nothing like the noisy,first breath of life from your collection of parts to motivate you to finish the build!
I've used a number of different brand of aftermarket FPR's (Aeromotive, Mallory, Holley, Summit) over the years and none would reliably hold pressure after shutting the engine off like an OEM FPR could. Most will bleed pressure off in a few minutes, wheres the OEM unit would still be solid after days parked in the garage. I've been running the same Mallory FPR for more than 15 years now. It still bleeds off pressure relatively quickly, but never fails to start and run reliably.
as mentioned earlier, I'd get rid of the FPR mounted pressure gauge. replace it with a Schrader valve like this:
https://www.summitracing.com/parts/ear-9616sverl
Then you can use a portable. diagnostic FP gauge when you need to confirm pressure.
Sean
Hey Sean, I was going to cap it, but tthe schrader valve is a great idea. Just placed an order.
I just replaced the battery and that didn't fix anything with the hard starts. I'm wondering if I have a leaking injector or something with the high pressure direct injection sensor. Still takes a very long time to crank after sitting for even 2-3 hours.
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Originally Posted by
canuck1
That is a fantastic idea! Cant get rid of the threads for a leak point once they are there so might as well make it semi functional. As long as you get a good Schrader, I like it.
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Originally Posted by
hennessyVV
Hey Sean, I was going to cap it, but tthe schrader valve is a great idea. Just placed an order.
I just replaced the battery and that didn't fix anything with the hard starts. I'm wondering if I have a leaking injector or something with the high pressure direct injection sensor. Still takes a very long time to crank after sitting for even 2-3 hours.
I had a Holley FPR that bled fuel from the vacuum port due to a failed bladder. They do make replacement parts to fix them, but like most things these days, it's probably more cost-effective to simply replace it
If your FPR is bad, it may be affecting actual fuel pressure to the injectors when cranking. I won't pretend I know anything about the Coyote but I'd definitely sort out the FPR issue first for safety reasons alone.
Sean
MK 3.5 roadster (MK IV body retrofit to MK III chassis) 396W stroker, Edelbrock Pro-Flo 4, AFR 195CC Renegade, XE274HR, GP 4-1-4 SS headers, 3link, 3.73, 15" Halibrand replicas, SAI mod, bumpers, 2 X roll bars, IČ electronics, PS, hydroboosted brakes: 95 GT front, custom MK VIII calipers/Cobra discs rear, FFR front, Levy rear LCA's, Forte front, VPM rear bars, CF dash, mod comp layout w/Auto Meter Ultra-Lites, Lucas tri-bar headlights, coupe taillights, painted by SRP (again!)
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I went with the Tanks brand and it will hold pressure for days and fires up immediately. I went with them because they were the least expensive and was so impressed I bought another for the type65 build.