Coyote Loses Power Under Heavy Acceleration

[Redlinejoev]

I have a frustrating and potentially dangerous issue with my Coyote powered MK4. The engine is a Gen 3. What happens is when I'm driving and try to accelerate at a moderate to heavy acceleration, the engine loses power. I hear a "putt putt putt" and step on the loud pedal and nothing happens, engine won't rev up. So last time this happened I was on the freeway and went to pass a truck and it happened again. I immediately shut the car down and and tried to restart it but same thing, pedal was no use. I turned on my 4-ways and tried to get to the right shoulder and almost got rear-ended by another vehicle. It's done it in the past and I shut it down and restart it, and everything is back to normal. Normally runs perfectly and from a dead stop I can stomp on it and row through the gears without issue so it seems to be an intermittent problem. I was thinking it may be a fuel pump issue. What do you guys think it might be? Any help is greatly appreciated and thank you in advance.

[Jeff Kleiner]

You'll need to start by seeing what fuel pressure is doing when it occurs. I've done this by adding a long hose on my fuel pressure gauge and taping it to the windshield so that I can see it in real time. If it drops when the problem occurs the first check would be the fuel filter.

Jeff

[Redlinejoev]

Thanks Jeff, I didn't even consider the fuel fuel filter. And I'll try to do what you did with the regulator gauge.

[nuhale]

Couple thoughts:
1. Agree w/ Jeff, sounds like a fuel issue
2. Did you have the engine tuned? Gen 3+ don't like things until they are tuned but your problem seems less tune related
3. Are you throwing a code? Sounds like something that should give you computer code if something wrong with crank, cam or knock sensors.
4. Air intake setup: What did you use? I've heard that the MAF sensor likes a very certain position, but I've never encountered it. MAF could be a culprit.

[Redlinejoev]

Yes, I had the engine tuned, twice actually because of this issue. I initially thought it was a tuning problem so I went back to my tuner and he ran through again, and I thought that would be it.
No codes! I used the intake setup that FFR supplies with the complete kit. I'm with Jeff roo on this. It might be a fuel pressure issue or the filter. Filter is fresh and so was the tank. Only have 1500 miles on it so far. I'm going to try turning up the fuel pressure 5 psi and see if that cures the issue. Thank you!

[michael everson]

Did you use the oil pressure sender that came with the Control pack? If not put it in. Fixed one of my friends coyote.
Mike

[TTimmy]

I struggled with intermittent fuel starvation issues for a few months. In my case the root cuase was faulty wiring on the inside of the FFR supplied fuel hanger assembly. I replaced it with an aeromotive hangar/pump aseembly and that addressed my issue for the most part.

I say "for the most part," becuase if I run my tank low (below 1/4 tank) I may still have issues if accellerating or turning aggressivly. In this case it seems to simply be a lack of fuel available for the pump to pick up. So, in my case, this situation is self-inflicted and I simply need to keep the fuel level higher.

Good luck getting this sorted!
Tim

[nuhale]

Only other thing I can think of is the pump. What are you using?

Many have had issues with the connector to the fuel pump hangar in the ron francis harness. This could be an area as well but this is usually on or off, not a loss of power.

[Redlinejoev]

Did you use the oil pressure sender that came with the Control pack? If not put it in. Fixed one of my friends coyote.
Mike

You know, I don't recall if mine came with one but if it did, I should still have it. Thanks for the idea.

[Redlinejoev]

Only other thing I can think of is the pump. What are you using?

Many have had issues with the connector to the fuel pump hangar in the ron francis harness. This could be an area as well but this is usually on or off, not a loss of power.

I'm trying to remember if there was a name on the fuel pump. For some reason Walbro comes to mind. But then again with my memory it's probably something I read online somewhere. It's the pump that came with Coyote kit from FFR.

And I guess it could be the connector to the fuel pump hanger. But I don't think so.

Thanks, Joe

[Indy Shu]

I've had the same thing happen a couple of times on the track, I think always when I've dropped the hammer coming off a turn. Would stay idling, but pedal was dead. Would have to turn off for a minute or two. I focused on my harness connections at the pedal and throttle body, and the splices where I tied in the cruise control. Not sure if problem still exists, need to get back out soon. I think I had plenty of fuel and did not show any codes.
Good luck

[Dave Howard]

I had a similar condition a few years ago with a Gen1 Coyote. After a bunch of trouble shooting I pulled the fuel pump from the tank. The little filter boot on the pump suction had fallen off. There is a screen mesh at the suction and it was clogged with dirt. I flushed that out and installed a new filter on the suction. The issue disappeared

[Redlinejoev]

Thanks Dave. I think dropping the tank may be in my future if nothing else works out.

[danmas]

I’m pretty new to this but maybe this is helpful…

What ecu are you running? If it’s a terminator x you can start logging and try and replicate the issue. When it happens, you can see exactly what happened and that may point you to the issue. Worth considering if you are logging fuel pressure and CTS and tps and afr and and…

Worth considering perhaps, particularly if you can log…

Dan

[Al_C]

Having had similar issues in a Gen II, I agree with Bryan and Jeff.

What size lines are you running? If 5/16, you will be much more sensitive. Your most likely culprits are the filter and the pump size. You said you had a tune done, so your engine may require more fuel now. My issue was the filter, but I put a bigger pump in while I was at it.

The fuel pressure will give you the most accurate picture of what's going on.

[Redlinejoev]

I’m pretty new to this but maybe this is helpful…

What ecu are you running? If it’s a terminator x you can start logging and try and replicate the issue. When it happens, you can see exactly what happened and that may point you to the issue. Worth considering if you are logging fuel pressure and CTS and tps and afr and and…

Worth considering perhaps, particularly if you can log…

Dan

Thanks Dan. Unfortunately I'm not running that ecu, I'm using the stock on from Ford and had the car dyno tuned.

[Redlinejoev]

Having had similar issues in a Gen II, I agree with Bryan and Jeff.

What size lines are you running? If 5/16, you will be much more sensitive. Your most likely culprits are the filter and the pump size. You said you had a tune done, so your engine may require more fuel now. My issue was the filter, but I put a bigger pump in while I was at it.

The fuel pressure will give you the most accurate picture of what's going on.

My lines are 6AN which is equivalent to a 3/8 line so I think it should be fine for stock 5.0 Coyote. I like where your thinking is going though. Maybe it's the size of the pump. I'm still doing more investigating on it so I'm checking things off the list. Thanks for your help!

[danmas]

Will this work?

bbfly BF32302 USB FTDI chip compatible HS-CAN/MS-CAN for Forscans OBD2
(https://www.amazon.com/bbfly-BF32302-modified-Windows-ELMconfig-Forscan/dp/B01N9R9QS2/ref=sr_1_1?crid=37BYKLN1PRAJL&dib=eyJ2IjoiMSJ9.DHElsV0hrvDtwXL-5Vtu2eX9EGOdx6xWEEFM9xNWC53GjHj071QN20LucGBJIEps.e BEjJ1Ar8n3NRMtVItBXfoRzhQiNmSrHrdvYzKAk4JM&dib_tag=se&keywords=bbfly+BF32302+USB+FTDI+chip+compatible+HS-CAN%2FMS-CAN+for+Forscans+OBD2&qid=1753219440&sprefix=bbfly+bf32302+usb+ftdi+chip+compatible+hs-can%2Fms-can+for+forscans+obd2%2Caps%2C202&sr=8-1)

And the Forscan (https://forscan.org/download.html) software

[Stangarang]

The FFR supplied hanger is known for failures. Pro-M has a really good hanger with larger return port already installed. That's if that is the problem. I hope this helps.
Michael

[Erik W. Treves]

Do mess with adjusting fuel pressure - the ECU and injector pulse width is based on a known base fuel pressure.

A may have missed it - but is the car throwing any codes when you scan it?

you could have an obstruction in the line or filter... where when it's cold and no pressure the obstruction is "laying flat" then as you run it finds its spot and fuel pressure decreases. Really need to look at the pressure when this happens... I had stuff in my filter one time that would stack in the screen after about 30 minutes and the car would lose power - shut it off for 30 minutes and it was fine for a bit.

[Redlinejoev]

Thanks to danmas, Erik and Michael.

[Redlinejoev]

Do mess with adjusting fuel pressure - the ECU and injector pulse width is based on a known base fuel pressure.

A may have missed it - but is the car throwing any codes when you scan it?

you could have an obstruction in the line or filter... where when it's cold and no pressure the obstruction is "laying flat" then as you run it finds its spot and fuel pressure decreases. Really need to look at the pressure when this happens... I had stuff in my filter one time that would stack in the screen after about 30 minutes and the car would lose power - shut it off for 30 minutes and it was fine for a bit.
No codes and I've adjusted the fuel pressure up 5 psi. My next step it to check the filter or just replace it. If that doesn't solve the issue I'll probably drop the tank and inspect the fuel pump hanger. Thank you Erik.

Joe

[Ray from Long Island]

Hi Joe,
Did you ever solve this issue?
I had the same problem over the weekend, engine & car have less than 2,000 miles on them.
Thanks !
Ray

[Redlinejoev]

Hi Joe,
Did you ever solve this issue?
I had the same problem over the weekend, engine & car have less than 2,000 miles on them.
Thanks !
Ray

Hi Ray,
Ive recently purchased a new fuel pump hanger from Fuel Pump Factory, they have the hanger with the return tube that goes to the bottom and the larger 3/8" return line. If you go to the Pro-M Racing website, they have a video that explains how the stock hanger creates cavitation and aeration of the fuel near the pump cuasing it to send aerated fuel to the engine. I was going to order the Pro-M part but too many people report issues with shipping and not receiving their parts. Ive also upgraded to a 340 lph pump and a 10 micron filter. I have yet to receive the parts but will be dropping the tank soon so I can upgrade the fuel lines and pump hanger. I'll let you know after I install them if this was the cause of the issue.

[Redlinejoev]

Hi Ray,
Ive recently purchased a new fuel pump hanger from Fuel Pump Factory, they have the hanger with the return tube that goes to the bottom and the larger 3/8" return line. If you go to the Pro-M Racing website, they have a video that explains how the stock hanger creates cavitation and aeration of the fuel near the pump cuasing it to send aerated fuel to the engine. I was going to order the Pro-M part but too many people report issues with shipping and not receiving their parts. Ive also upgraded to a 340 lph pump and a 10 micron filter. I have yet to receive the parts but will be dropping the tank soon so I can upgrade the fuel lines and pump hanger. I'll let you know after I install them if this was the cause of the issue.

Update: I installed all the parts listed above and I still have the issue. I can accelerate from a dead stop full throttle with no issue, it's only when I accelerate when trying to pass a slower vehicle. I step on the go pedal, I hear a backfire and suddenly I lose power. I step on the pedal and nothing. While still rolling I shut the car down and restart it and it's fine again... I'm starting to think it's a sensor somewhere, perhaps TPS?

[TXeverydayDad]

Have you checked all grounds/power cables? Are you getting any codes? My Coyote died at a traffic light but it would occasionally lose power as well.

[Redlinejoev]

Have you checked all grounds/power cables? Are you getting any codes? My Coyote died at a traffic light but it would occasionally lose power as well.


I've double checked my connections and grounds. Everything seems ok there, although I do wish it were something that easy. Thank you for the suggestion, I appreciate any help.

[Jryasko]

Have a Gen 3 myself. Double check if you have a code right after it happens. Look for a P061B. If you have that it is a issue your tuner will have to resolve. Currently in the middle of this with my tuner. Cars runs great, unless you go to pass drop a gear and really get on it. When you let off the throttle its like it has a jake brake like a diesel and really burbels through the exhaust. It goes into a limp mode and retards the timing. Shut if off, wait a minute or two restart its normal. Not trying to confuse you but others have had this issue. I just did a Data Log for my tuner and he said the throttle body was going into limp mode. He just revised my tune and sent it back, but the weather in N IL is not cooperating at this point for another Data Log.

[Redlinejoev]

Have a Gen 3 myself. Double check if you have a code right after it happens. Look for a P061B. If you have that it is a issue your tuner will have to resolve. Currently in the middle of this with my tuner. Cars runs great, unless you go to pass drop a gear and really get on it. When you let off the throttle its like it has a jake brake like a diesel and really burbels through the exhaust. It goes into a limp mode and retards the timing. Shut if off, wait a minute or two restart its normal. Not trying to confuse you but others have had this issue. I just did a Data Log for my tuner and he said the throttle body was going into limp mode. He just revised my tune and sent it back, but the weather in N IL is not cooperating at this point for another Data Log.


That is exactly what I'm experiencing with my car. I'll have to get an OBDII scanner to see if there's any codes. The light is not on so I've assumed no codes. Thanks a lot!

[Railroad]

My Coyote is a Gen 1 Aluminator. While down loading for the tuner, I made a WOT run from about 2K to 7K rpm, when I let off the throttle the engine was dead. I coasted to road side, tried to restart. It started and ran fine the rest of the trip home. I called the tuner and he ask to see a picture of my air intake with MAF sensor location.
I cannot post pic now, so to describe it, I had a straight tube off the TB with the MAF sensor about 6 inches from the TB.
Tuner said MAS too close to TB, computer could not respond to the abrupt air changes with being too close.
Just throwing this out there, if it might be relative.

[Jryasko]

Please update when you have a chance to check on the code. The MIL light may be on very faintly, thats not uncommon and not an issue.

[Redlinejoev]

My Coyote is a Gen 1 Aluminator. While down loading for the tuner, I made a WOT run from about 2K to 7K rpm, when I let off the throttle the engine was dead. I coasted to road side, tried to restart. It started and ran fine the rest of the trip home. I called the tuner and he ask to see a picture of my air intake with MAF sensor location.
I cannot post pic now, so to describe it, I had a straight tube off the TB with the MAF sensor about 6 inches from the TB.
Tuner said MAS too close to TB, computer could not respond to the abrupt air changes with being too close.
Just throwing this out there, if it might be relative.

The funny thing is, I took it back to the tuner and he didn't mention anything like this about the MAF being to close to the TB. He simply just turned it again and charged me another 300. I'll keep this in mind and probably go to a different tuner.

Thanks for your input.

Joe

[Redlinejoev]

The funny thing is, I took it back to the tuner and he didn't mention anything like this about the MAF being to close to the TB. He simply just turned it again and charged me another 300. I'll keep this in mind and probably go to a different tuner.

Thanks for your input.

Joe

So to update, I've installed the fuel pump hanger and Aeromotive fuel pump and the larger return line. It would crank at least a dozen times before it would start, now that issue is gone as it starts right up. I procured a code scanner and found one code, p0507, which denotes an issue with the idle air control. It idles fine but after about 5 seconds the idle jumps to about 1100. The other issue I was having that didn't go away is the losing power during acceleration. Could it be the fact that I don't have a vacuum hose attached to the fuel pressure regulator, it's vented to the atmosphere per instructions I read somewhere. Does anyone have theirs connected to vacuum?

[Railroad]

Mine is open. It has a piece of open cell foam on it to prevent insects from building a home inside.

[Redlinejoev]

Mine is open. It has a piece of open cell foam on it to prevent insects from building a home inside.


Thanks Railroad! I'm glad to hear I'm not the only one, I got something right. I sourced an open plug with a screen to prevent dirt and such from entering.