Coyote hesitation question Update

[cfriedman67]

I have a coyote gen3 tuned by Lund last September 2022. I have about 1300 miles on the engine. last year I noticed that when going around a tight turn and coming out of it the engine would hesitate like it wasn't getting any fuel. It happened a few times but forgot about it over the winter. As the weather has gotten nicer I have taken the car out for a few drives and same issue has arose. When going around a tight turn and coming out of it the car will hesitate like it is starved for fuel and then take off. Can this be an issue caused by the Tune or something else? usually I am in second or third gear if that matters.

thank Craig

[jiriza84641]

Try removing the fuel pump, and verify there is no blockage. I have a lund tune as well and do not have that issue.

[Hoooper]

Grab a scanner and log the fuel pressure when this is happening

[Fman]

How much fuel did you have in the tank? I had same issue with my EFI 427 when tracking it, would take a hard turn and low fuel (less than half tank) would actually cause the engine to starve because the pump would go dry for a quick second.

[cfriedman67]

It happens usually with less than 1/2 a tank as well. I would imagine that wouldn't happen as it doesn't happen with other cars i drive. Is there something that can be done to combat that other than always having more than a 1/2 a tank of a gas?

[cfriedman67]

what type of scanner? I have the HP scanner from the lund tune.

[Fman]

It happens usually with less than 1/2 a tank as well. I would imagine that wouldn't happen as it doesn't happen with other cars i drive. Is there something that can be done to combat that other than always having more than a 1/2 a tank of a gas?

Good question the Mustang tank I believe has no baffles so the fuel will slosh to one side. More than likely only happening when you make a right turn which will pull fuel away from the pump. Easiest solution when you take your spirited drives make sure you are topped off :cool:

[Jeff Kleiner]

Good question the Mustang tank I believe has no baffles so the fuel will slosh to one side. More than likely only happening when you make a right turn which will pull fuel away from the pump. Easiest solution when you take your spirited drives make sure you are topped off :cool:

The Mustang tank has a baffle—a 4 sided open top box, maybe about 6” each side—-that surrounds the pump. It would take some sustained high G cornering with a low level to empty the fuel from it and uncover the pickup.

Jeff

[cfriedman67]

not sure if left or right turns make it happen but I will give it a try.

[cfriedman67]

thanks Jeff. I m pretty sure it does happen only when take is less then 1/2 full. I will definitely check it out and see when it happens.

[Al_C]

What are you using for a fuel pump? OK, that's a rhetorical question. I think this is your issue. I also wonder (rhetorically) if you're getting any codes. My guess is that you put in a "stock" pump when you built the car and it worked fine. Then you got the tune and now you're having issues. Your pump could quite possibly not be providing enough fuel for the more efficient engine.

My Gen II ran fine until I got a tune. Then I started having problems where it was starving for fuel. I got two different codes, the more serious being a lean condition. The problem was that the original pump was too small given that the engine was generating more power and wanted more gas. I'd try a bigger pump. Just my 2 cents.

[Alan_C]

If you pull the pump and find there is not much in the way of baffling, I was going suggest one of the Holley fuel mat products. I saw was because I had no idea how much they are asking for these mats. The smallest is almost $200 with the largest exceeding $600. If the pump appears to be adequate in pumping volume, maybe something to consider even at the high prices.

[edwardb]

My Gen 3 powered Coupe with a Lund tune doesn't do that. Never hesitates in any situation. I agree with the thoughts about the fuel pump. Also check you have the proper fuel pressure. The fact that it only happens with less than half a talk is certainly a tell for the tank or pump.

FWIW, my Coupe has a Walbro GSS340BX pump (255 lph) on a Pro-M Racing High Flow Fuel Pump Hanger, an Aeromotive Universal 13129 Bypass Regulator set at 60 psi at idle with vacuum reference open to atmosphere. Per Lund Racing. Fuel lines are a combination of rigid 3/8 stainless and Aeroquip TFE Racing Hose.Trick Flow TFS-23006 filter. Second build with the same setup. Other was in a Roadster with a Gen 3 Coyote. Also rock solid.

[Fman]

The Mustang tank has a baffle—a 4 sided open top box, maybe about 6” each side—-that surrounds the pump. It would take some sustained high G cornering with a low level to empty the fuel from it and uncover the pickup.

Jeff

Apparently the baffles didn’t work for me on the track under hard right turn acceleration, granted my BIL who races cars was pitching the car much harder than I would (with me white knuckling the grab bar :-) but a definite fuel starvation issue. When we ran with fuel topped off did not have any hesitation issues.

[Railroad]

Are your cold air intake tubes and MAF tube and sleeves all tight and closed? I did a test ride with a car engine would break up at load in a right hand turn. The weight of the cold air tube and the engine tq would pull the sleeve after the MAF tube, open and let un metered air into engine. Rare huh!

[ADI]

Are you using the internal fuel pump? There is a slight chance that when installing it, your tube did not aligned properly with the small squared baffle and is sitting outside. worth the check.

[cfriedman67]

Sorry to say not sure what fuel pump it is but I purchased it from Mike Forte with the engine. I will check the fuel pressure next weekend when I am with the car.

[Al_C]

If you are running 5/16 fuel lines, you probably got a 155 lph pump. You can go to a 190 in that case. If you are running 3/8, the sky's the limit and I'd go with a 255. Here's an interesting caveat, though- if you use the stock pump hanger that comes with the car (at least it came with mine), the pump connection out through the tank is 5/16, and your stock fuel filter that comes with the kit is 5/16, so you are still effectively running 5/16. I know, probably too much information, or it may be outdated information because I'm old and haven't peeked inside one of the boxes that arrive with the kit in several years.

When I was dealing with my fuel challenges, I put a 45 degree angle on the pressure regulator gauge connection so I can read the gauge without a mirror. I've seen a few others do that as well and I think it's a good idea.

[weendoggy]

The Mustang tank has a baffle—a 4 sided open top box, maybe about 6” each side—-that surrounds the pump. It would take some sustained high G cornering with a low level to empty the fuel from it and uncover the pickup.

Jeff

Which Mustang tank? The Cobra, yes, stock GT no, provided these are the SN95 1999> tanks. I'm also curious if all of the installs are running a returnless system.

[cfriedman67]

Is there a way to tell? The gas tank and the rear end are the only not new pieces on the car?

[weendoggy]

Is there a way to tell? The gas tank and the rear end are the only not new pieces on the car?

If you're asking about the fuel tank, a stock New Edge GT tank has the pump/sender in the middle of the tank. Once the "hat" is off, the unit comes out the top and is enclosed in a plastic housing. If you have a return style system, you'll have one feed from the pump and one line returning to the tank (usually at the hat). So, if you don't have a return line, you're running a returnless system and pressure is modulated by the ECU. Another quick check on fuel system is if you have a regulator in-line or a return style fuel filter with regulator built in, it's a return style system.

[Jeff Kleiner]

Which Mustang tank? The Cobra, yes, stock GT no, provided these are the SN95 1999> tanks. I'm also curious if all of the installs are running a returnless system.

For clarification, I was referring to a Fox era tank which is what FFR provides with complete kits. Here's what they look like out of the tank; the pickup sits inside of the box. With age these are known to break free of the tank and move around...had it happen to my own car years ago.

https://www.corral.net/attachments/dsc04313-small-jpg.977832/

Jeff

[cfriedman67]

Attached is the fuel pump I am running. I believe it’s attached on the right side and not in the middle. 184780184779

[Hoooper]

what type of scanner? I have the HP scanner from the lund tune.

HPtuners scanner? Should have no trouble logging fuel pressure during a hard turn and breakup using the VCM scanner suite if thats the case.

[Al_C]

Attached is the fuel pump I am running. I believe it’s attached on the right side and not in the middle. 184780184779

If that's your pump, and it's working correctly, you are certainly not starving for fuel. Not with 340 lph. How's the fuel pressure at the regulator? I'd also check the flow through the filter. That's it for my ideas.

[cfriedman67]

That my pump. I will need to check fuel pressure this weekend. Does it matter when its checked? What I mean is at start up or after the engine is warmed up or both.

[edwardb]

That my pump. I will need to check fuel pressure this weekend. Does it matter when its checked? What I mean is at start up or after the engine is warmed up or both.

I set mine per the Ford Performance control pack instructions: 65 PSI with it at idle. Engine temp doesn't matter. It also says 55 PSI with the engine off. But the fuel pump only runs briefly with the engine off, so not easy to check unless you hot wire it. Not needed in my experience. As Al_C said, that's a lot of pump for a stock Coyote. Hopefully you're running 3/8" supply and return lines. With that combination, you shouldn't be having any fuel starvation issues.

[cfriedman67]

For argument sake if the fuel pressure is low at idle can I adjust it with getting it tuned again? Also, this weekend the fuel gauge is less than 1/2 full. I am going to make some hard left and right turns and see if it really only happens when turning right. I will also do this with a full tank and see if it is any different.

Thanks

[weendoggy]

For argument sake if the fuel pressure is low at idle can I adjust it with getting it tuned again? Also, this weekend the fuel gauge is less than 1/2 full. I am going to make some hard left and right turns and see if it really only happens when turning right. I will also do this with a full tank and see if it is any different.

Thanks

Yes, set it with engine idling.

[Hoooper]

Just get a log of this happening and you will have a pretty good answer whether its fuel or not.

[Dave Howard]

The hesitation when turning may be a red herring. Have you pulled the pump from the tank to inspect the inlet filter sock and screen? You may have accumulated some dirt in the tank during your build.
I developed similar hesitation with my Coyote and found the filter on Miya in tank pump was full and had fallen off, and the the screen at the inlet of the pump was blocked. Cleaned screen and replaced inlet filter….issue resolved. 10 years in and still having a whale of a time.

[cfriedman67]

So I drove the car with a 1/3 of a tank of gas today. When making hard left hand turns no hesitation or issue at all. When I would make spirited right hand turns the car will hesitate for a second until it straightens out and then takes off again. Right hand turns move the gas to the left side of the tank away from the pump. I then filled the car up to full and absolutely no issue with hesitation when Turing left or right. I spoke with Lund and they also said it’s the gas sloshing around in the tank and to go fill up. I did not send them a data log but explained my issue. Do you all think it’s the tank, seems like a cheap fix. Any other thoughts? It isn’t difficult to keep more gas in the car either. Last, my fuel pump reads around 58 when idling. Is it imperative to get it to 65 PSI? If I adjust it will it screw up the tune?

Craig

[JeffP]

Just for an added data point - I have the same engine, Lund tune, and same fuel pump from Mike. I did purchase my gas tank from Amazon though because FF was backordered and it was holding me up. I'm 99% sure there were some sort of baffles in it as I had to maneuver the fuel pump a few times to get it to go in without hitting them.

https://www.amazon.com/gp/product/B000IZ9R06/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[cfriedman67]

Thanks. It just might be a fall project.

[Hoooper]

If only there were a diagnostic tool that could be used to eliminate guessing...

[Bob Cowan]

This is clearly a fuel delivery issue. It would happen no matter what engine was under the hood. It's a common problem with Mustangs, because the fuel pick up is in the far right side of the tank. When you turn right, the fuel moves left, uncovering the intake.

As Jeff mentioned, stock tanks come with a baffle of some sort. Some are more effective than others. But, over time, they do tend to break loose, and wander around the tank, doing nothing for you. There really is no way to fix that without cutting the tank open and welding it back in place.

If your baffle is still solidly in place, make sure the return hose is also inside the baffle.

Since I was racing my car, I replaced the stock tank with a fuel cell. A fuel cell has an excellent slosh box solidly mounted. It also has foam in it to help control fuel movement. Kind of expensive, but a good choice for me at the time.

The Aeromotive Phantom system might be a good idea. Especially if you mounted it in the center of the tank.

But, the best option for a street car is the Holley Hydramat. Certainly the cheapest and easiest to install option. It just snaps on the bottom of the pump like the stock fuel sock. I have one in my track car to prevent the same problem you're having. Works like magic.

[cfriedman67]

This is clearly a fuel delivery issue. It would happen no matter what engine was under the hood. It's a common problem with Mustangs, because the fuel pick up is in the far right side of the tank. When you turn right, the fuel moves left, uncovering the intake.

As Jeff mentioned, stock tanks come with a baffle of some sort. Some are more effective than others. But, over time, they do tend to break loose, and wander around the tank, doing nothing for you. There really is no way to fix that without cutting the tank open and welding it back in place.

If your baffle is still solidly in place, make sure the return hose is also inside the baffle.

Since I was racing my car, I replaced the stock tank with a fuel cell. A fuel cell has an excellent slosh box solidly mounted. It also has foam in it to help control fuel movement. Kind of expensive, but a good choice for me at the time.

The Aeromotive Phantom system might be a good idea. Especially if you mounted it in the center of the tank.

But, the best option for a street car is the Holley Hydramat. Certainly the cheapest and easiest to install option. It just snaps on the bottom of the pump like the stock fuel sock. I have one in my track car to prevent the same problem you're having. Works like magic.

Hi Bob, thanks for the info. I am also convinced that it is the gas sloshing from side to side. I plan on calling Holley to order one. I see there are all sizes and shapes. Do you recommend one size/shape for our gas tanks? I will also ask Holley for there input as well. Appreciate the help and info.

Craig

[Bob Cowan]

Get the longest one that will fit, and position it so it points to the left of the tank.

There are only a couple that will snap on in place of the sock, be careful about which one you order.

[k-roy]

Might have some interesting reading for you. Look at page 18 at the fuel pump location. It has interesting things to say about cavitation, fuel pumps, filters, and associated road conditions.

https://www.performanceparts.ford.com/download/instructionsheets/FORDINSTSHTM-6017-M50B.PDF

Question might be with a 340 lph pump and depending on your fuel line size (specifically pick up and/or filter), is the pump causing cavitations which causes your hesitations? This might be affected by road conditions, not necessarily turning right.

[Vince4]

Instead of replacing the fuel tank with a fuel cell, wouldn't an external surge tank be the more convenient option to the problem? Unless you plan to track your car regularly and they require a fuel cell for safety.

Since the issue is that the fuel is drawn away from the in-tank pump for periodic cornering, a surge tank would be kept "full" and won't experience fuel sloshing. The surge tank can go inline of the existing fuel system without having to modify for the cell. Plus it will add a little bit of capacity.

[Gbeck]

I also have fuel starvation issues. It's a Gen2 Coyote with an RCI fuel tank with no baffles and an external fuel pump. The pick up is center-forward in the tank. With less than half a tank of fuel I have to be careful to not cause a temporary starvation issue by strong acceleration or turns.
Some have had success with Hydramat. But I'm going to install a surge tank when the car is off the road next winter.

[cfriedman67]

I am going to try th hHydramat sometime over the summer.