Possible Venturi fuel tank issue

[Pistol_91]

The nozzle is only .017". You'd basically have to pop the venturi block out of the bottom of the bucket then force water or air backward through it. But if it's a tiny piece of trash, then blowing air or water might push it out of the hole but probably not completely out of the block. It will be tricky to clean it good, but not impossible.



It holds a good bit. The hump is higher than you'd expect. However, the PS venturi is always pumping fuel over to the DS saddle. I'm guessing if there's about 1/3 of a tank left, I'd expect the PS of the saddle to be completely empty and you're just running off the DS saddle. The fuel gauge averages the reading from both sides and applies a rolling average to dampen fluctuations.

I got cha. Makes sense. I will have to pull both sides and examine everything thoroughly.

What is the purpose of this spring here? From memory, there is also one on the driver side correct?

Sponsored

 

[engineermike]

I got cha. Makes sense. I will have to pull both sides and examine everything thoroughly.

The PS is just a pickup. I suppose it's possible the pickup is plugged, but unlikely in my opinion. There are no small orifices in the PS.

What is the purpose of this spring here? From memory, there is also one on the driver side correct?

Both sides are spring loaded to ensure the pickups are as close to the bottom of the tank as possible. It spring-loaded with some travel to accounts for production variances.

 

[NightmareMoon]

Yeah the spring just allows them to sit at the bottom without actual bolts or fasteners on the bottom of the tank that presumably could leak or rust. It has nothing to do with fuel flow.

My guess is one of your two senders is sticky. Check that they move freely. If you had a weak venturi it would indicate having a third of a tank but I’d guess you’d fuel starve at higher rpm under load.

 

[Pistol_91]

Got cha. The DS only has one spring. Does I matter which sleeve it's in? I do recall when I swapped the fuel pump out, the spring popped up and I don't remember which side I put it back in.

Around 1/4 tank I do have fuel starvation at WOT.

 

[engineermike]

I don’t think it matters which hole the spring goes in.

 

[NightmareMoon]

Are your fuel trims ok? Is the tune driving the pump voltage ok? If the venturi is clogged that checks out. If its not clogged, then could be a weak fuel pump too. If the fuel trims are positive that would indicate to me that the pump itself could be weak.

fuel starving at 1/4 tank indicates its running out of fuel in the drivers side hat, which is consistent with either a weak pump (causing weak venturis) and/or clogged filters/venturis.

 

[John S]

What’s interesting is that there is a tiny filter just ahead of the venturi nozzle which means the debris had to originate in the tiny space between the filter and the venturi block or from inside the block itself.

Since Ford is dragging their feet on the recall (how could they not even formally disclose the root issue one year after announcing the recall) and the OEM system design has it own venturi concerns, I took the easy way out and replaced my OEM pump assembly with the KPM800 drop-in bucket replacement, just like the Dark Horse Track Attack cars. Is there anything between the passenger side transfer line and new pump assembly that needs further attention?

 

[engineermike]

Since Ford is dragging their feet on the recall (how could they not even formally disclose the root issue one year after announcing the recall) and the OEM system design has it own venturi concerns,

There is some information that was published here RCLRPT-25V455-7716.pdf that says "Teardown analysis indicated that jet pump orifices on some returned parts were blocked by contamination." That's where my conclusion came from, because the venturi in the jet pump is only .017" in diameter it made sense. There is some very confusing verbiage later in the document that muddies the water a bit though.

I took the easy way out and replaced my OEM pump assembly with the KPM800 drop-in bucket replacement, just like the Dark Horse Track Attack cars. Is there anything between the passenger side transfer line and new pump assembly that needs further attention?

If my interpretation is right, then you probably avoided the issue. However, I wouldn't run without a main fuel filter, which KPM now offers.

Did KPM revise the wiring on their lower end kits? I could have sworn that there were wiring changes in the instructions but I don't see them now. I appears to plug right into the stock connector with no additional wiring.

 

[Pistol_91]

Are your fuel trims ok? Is the tune driving the pump voltage ok? If the venturi is clogged that checks out. If its not clogged, then could be a weak fuel pump too. If the fuel trims are positive that would indicate to me that the pump itself could be weak.

fuel starving at 1/4 tank indicates its running out of fuel in the drivers side hat, which is consistent with either a weak pump (causing weak venturis) and/or clogged filters/venturis.

Fuel pump should be fine fuel trims trend lean once the lift pump pressure drops. Only happens with low fuel on e85. Me and Mike spoke about this some awhile ago, I'm pretty sure it's a venturi issue. Once the tank is half full or more the issue goes away.

What all should I replace? Both buckets and the crossover line?

 

[John S]

I wouldn't run without a main fuel filter, which KPM now offers.

Did KPM revise the wiring on their lower end kits? I could have sworn that there were wiring changes in the instructions but I don't see them now. I appears to plug right into the stock connector with no additional wiring.

KPM's Bosch single-pump replacemt assembly is as simple as it can get and installs in just a few minutes with the biggest challenge involving removing the float sensor from the OEM assembly and installing it on the KPM Bucket. Snaking the new bucket asssembly and float sender into the tank takes some finesse but so would the OEM unit. The factory pump harness plugs directly into the KPM module and the OEM FPDM should have no concerns managing KPM's single pump.

The filter is still a concern, I'm running E85 and I originally installed a Deatchwerks Ford direct replacement fuel filter with reusable 10 micron stainless steel mesh media mounted on the valve cover but I've since been advised that the 2018+ Coyote Direct Injection system is better protected by 6 micron microglass media so I'm switching to a larger capacity Radium Filter system I'm going to relocate somewhere under the cowl brace or strut tower brace. (That's this weekend's project if I can tolerate the heat and hazadardous air polution from the Canadian wildfires.)

Sponsored