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Old Feb 12, 2023 | 11:50 PM
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Fuel pressure fluctuations

When I bought my truck almost a year and a half ago it was extremely sluggish. It ran ok as long as I stayed off of the skinny pedal. After a good amount a research I went and got a mechanical fuel pressure guage. Hooked it up and the results were not promising. Went and got the items for a hutch mod and droped the tank.



Funds were tight at the time so I did not replace lines going into the sending unit. Nor did I buy new orings for them. That was just me being careless. I did have a drastic improvement in fuel pressure. Still had an issue at wot but other then that stayed in the green. So I disconnected my gauge put it in my tool box and left it there. Fast foward a bit I've modded a few things put a hydra on it and all of a sudden it's fun to drive. Unfortunately I started noticing my power was very inconsistent. For Xmas I decided it was time for a set of guages. 1 to protect my investment and 2 didn't look to cool with my mechanical guage ran out the top of my hood hanging on my mirror from a zip tie. Installed my guages and see where the inconsistencies were coming from. Fuel pressure sitting at 50 psi key on engine off. Crank it get out of the driveway builds up to about 55 psi. Let's the truck warm up hit the skinny pedal fuel pressure drops to 45 range at half throttle. Immediately regret not replacing those lines. So 80$ and a trip to the parts house later I return with 8ft of fuel injection hose. Get it installed double clamped no leaks no bubbles same issue. Runs quiter so I was pulling a small amount of air, but half throttle and bam fuel pressure drops to the 40-45 range. Frustration kicks in start looking for solutions. Decided to check my fuel filter has less the 2k still nice and clean. Pull it so I can check the for. Thought process was maybe its not seating properly pressure bleeding by who knows. Climb up on the pumper to get a better look and Holy ****.

Clean up what looks to be 600k worth of trash. Seems to be mostly clay. Living in east texas this thing was cover in red clay when i bought it. Clean the fpr as well make sure its seating properly. Prime it fire it up and holy **** 60 psi staying steady at wot. Turn up the tune. Best the truck has ran since i bought it. Next day crank her up same **** different day. Pulled the ff cap still clean. Check the fpr again. Small improvement but not long lived. Thinking I'll replace the fpr this weekend really hoping it solves my issue. Figure if not I'm gonna throw a fuel pump at it. Literally lol. If anyone else has any other thoughts or suggestions let me know. Starting to run out of ideas
 
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Old Feb 13, 2023 | 12:17 AM
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Dayum that fuel bowl was full of crap!

Just to be sure, you did a full Hutch and Harpoon on the fuel tank?

If replacing the FPR either go with a billet item or FRx.

Fuel pump will pump X psi and anything other than X psi is due to other factors.

I'm a big fan of a permanent fuel pressure gauge install.
 
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Old Feb 13, 2023 | 03:18 AM
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Is there any fuel filtration pre pump? It used to be those screens in the tank, but we saw how effective those were. If you added one during H&H I would be having a look at it. If not then consider this, that much BS got to the bowl. How much do you think might be packed in the pump? The factory pump have an internal mesh screen filter.
 
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Old Feb 13, 2023 | 03:21 AM
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Is there any fuel filtration pre pump? It used to be those screens in the tank, but we saw how effective those were. If you added one during H&H I would be having a look at it. If not then consider this, that much BS got to the bowl. How much do you think might be packed in the pump? The factory pumps have an internal mesh screen filter, so not much of a stretch to think it could be plugged also.
 
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Old Feb 13, 2023 | 03:49 AM
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Yes it was a full h and h I'm running the wix 33972 pre pump. I had to change it around Xmas we had a freeze and it geled up I broke the inlet getting it off. My fuel pump isn't stock best I can guess is it looks like a Delphi. Inlet and outlet both have removable fittings. Pump isn't loud at all. I've seen it get up to 60 psi just can't get it to be constant. I probably won't have time to do the regulator till friday so depending on how dirty my housing is then I may replace the pump and the rest of my pre filter fuel lines. Thinking of getting the xdp kit as it offers a new housing a all gaskets for fuel bowl for 35$. Eventually I'll upgrade but right now just looking for consistency. Truck has 600k and previous owner put alot of chinesium on it. Slowly going through it getting it right before I start trying to climb in power.
 
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Old Feb 13, 2023 | 07:21 AM
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This was my solution to the erratic fuel pressure. Just about every gasoline powered vehicle has the pump mounted in the tank these days and that's for good reason. It's way better to push a fluid rather than pull it. My fuel pressure was dropping to 20 PSI without even pulling a trailer and the power would drop off a cliff whenever I needed to climb a hill. This completely eliminated that issue and the truck now pulls like a bull elephant. There are some updates to these pictures in the form of I had to drop it back down to make the electrical more secure for longevity that I didn't take pictures of, but this system has been in my fuel tank for around 15 years now and it's been as reliable as an old tractor.



 
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Old Feb 13, 2023 | 07:26 AM
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Here is a volume test I performed between the two pumps.


 
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Old Feb 13, 2023 | 09:11 PM
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Not a bad idea. Only downside I see would be maintenance, but fabrication would be pretty straight foward. If my fpr doesn't solve my issue and I replace my pump I'll have to give that some thought. Which pump did you go with.
 
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Old Feb 13, 2023 | 09:39 PM
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A Bosch 69430 is what I used. Others have used the Bosch "044" pump. Both of them are larger in diameter than the factory Ford pump. Both provide a dramatic increase in fuel volume delivery over the factory Ford pump. Plus they don't have that idiot screen on the inside of the fuel pump inlet that gets clogged up and you cannot get at it to clean it out, either. Only choice at that point in time is to replace the fuel pump. I have the screen off of the fuel pickup installed on the intake of the fuel pump on my truck.
 
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Old Feb 13, 2023 | 09:40 PM
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Also maintenance for me has been a non-issue. Pump has been installed they way it sits now for more than ten years and shows no signs of me having to drop the tank for any reason.
 
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Old Feb 14, 2023 | 07:29 AM
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Originally Posted by JWHGreen7.3
My fuel pump isn't stock best I can guess is it looks like a Delphi.
I learned the hard way about going with an off oem brand fuel pump. Bought an off the shelf unit from Napa, I think it was a Carter. Made noise and vibrated but didn’t pump fuel. I had read about others having hit or miss luck with non bosch replacement pumps. I would pick up an oem Bosch pump if I were you. As mentioned above, if your fuel bowl looks like that your pump can’t be in that good of shape.
 
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Old Feb 14, 2023 | 09:12 AM
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Originally Posted by Kwikkordead
A Bosch 69430 is what I used. Others have used the Bosch "044" pump. Both of them are larger in diameter than the factory Ford pump. Both provide a dramatic increase in fuel volume delivery over the factory Ford pump. Plus they don't have that idiot screen on the inside of the fuel pump inlet that gets clogged up and you cannot get at it to clean it out, either. Only choice at that point in time is to replace the fuel pump. I have the screen off of the fuel pickup installed on the intake of the fuel pump on my truck.
I went w/ the 040 myself. It's the 044's slightly smaller but stronger cousin. Doesn't move quite as much fuel, something like 10-20 lph less, but rated to a little higher pressure 5 bar vs 6.5 bar. The 040 is also designed as an in tank only where the 044 can be run in line. Not sure on the one Kwik listed. I have no doubts it's up to the task, just that Bosch really doesn't put numbers out there so comparing parts can be difficult. It took me a week or more diving through the Googleverse in my spare time hunting specs for the 040 and 044, and honestly the numbers may not be all that accurate. Like I said my 040 is rated to 6.5 bar which is 94 psi, I've seen mine wrap a 120 psi gauge all the way back around to the 0 peg before I got it shut down, and that happened in an instant. Not like it was struggling to get there, made a believer in Bosch outta me.
 
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Old Feb 14, 2023 | 09:38 PM
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I've never had a Bosch part fail. 40 years as an auto shop owner and I cannot remember one instance where I had to warranty a bad part.
 
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Old Feb 15, 2023 | 03:44 AM
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I try to stay with oem when possible. I'll go with the bosche when I do a swap it out. I worked for O'Reilly auto parts probably 20 years ago when they stocked the bosche pumps and saw very few with issues. As for the one I have now it very well could be the source of my issue, but want to rule out the regulator before I drop another 100 on the fuel pump. I've been firing the buckzooka at it lately in the last month I've replaced the fuel line, oil change fuel filter change 4 new shocks cps. Near future new tires balljoints bushings etc. Front driver side tire started showing metal so want to get it aligned before I ruin a new tire. Everything looks tight but something has the camber off. I work 60 hrs a week and my wife doesn't like me spending too much time with the truck lol. So I'm left researching and doing quick little projects here and there. Probably for the best though.
 
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Old Feb 15, 2023 | 09:23 AM
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Originally Posted by JWHGreen7.3
I try to stay with oem when possible. I'll go with the bosche when I do a swap it out. I worked for O'Reilly auto parts probably 20 years ago when they stocked the bosche pumps and saw very few with issues. As for the one I have now it very well could be the source of my issue, but want to rule out the regulator before I drop another 100 on the fuel pump. I've been firing the buckzooka at it lately in the last month I've replaced the fuel line, oil change fuel filter change 4 new shocks cps. Near future new tires balljoints bushings etc. Front driver side tire started showing metal so want to get it aligned before I ruin a new tire. Everything looks tight but something has the camber off. I work 60 hrs a week and my wife doesn't like me spending too much time with the truck lol. So I'm left researching and doing quick little projects here and there. Probably for the best though.
OEM Ford pump is manufactured by Bosch. Stamped right into the side. If I could have figured out a way to dig that screen out of the inside of the pump to remove the blockage that was in there I would never have moved my fuel pump to the tank.
Apologies for the poor focus, but this shop towel shows how much debris I shook out of my fuel pump before I cut it open for fun. The screen was blocked up badly. It would idle with good fuel pressure all day long because the fuel demand was low. Soon as I go and drive the truck, fuel volume demand went up and then the fuel pressure would drop like a rock. Let off the throttle and fuel pressure would come back within seconds. I knew there was a restriction somewhere and it took me a while to finally figure it out by physically removing the fuel pump from the truck and looking down the intake side. VOILA! There was a pile of crud trapped inside the intake port of the fuel pump and I knew what had to be done at that point in time. The rest is history.

 
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