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Ford F-350 Super Duty XLT Lariat 7.3L IDI E4OD RWD
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Discussion Starter #1
Good morning, first time posting here so thanks in advance for any info gained, and all the info I’ve already read through!

I just purchased my first diesel truck, 1991 Ford F-350 7.3l IDI E4OD RWD, and it’s running pretty rugged. A couple of days ago it was starting perfectly, idling for days, but once put into gear it really drags. There’s very little throttle response, it takes forever to get up to 45mph(max speed), it’ll buck and shudder if pushed anywhere close to hard (acceleration wise), and when climbing gears, right now, it has a tough time shifting unless the accelerator is released enough for it to catch up. That’s the overall standing of the truck the past few days, but presently what’s happening is, it won’t crank and start unless I have a helping hand in the cab while I manually give it fuel from under the hood. After she starts up, it’ll idle for days, but all of the same symptoms I mentioned before still take place. Being the newb that I am my gut says there’s an issue with fuel delivery. But, before I go swapping parts because I don’t know any better, I wanted to consult some experts, to see where I should start poking and prodding for some answers?



Below I’ll copy and paste bulleted notes about info I got from/about the previous owner also so you get a better idea of what we’re dealing with here... I’ve also got pictures and videos to accompany for what they may be worth! I have access to tools, gauges, etc so I can try and provide whatever readings may be useful.





Previous Owner:



-Replaced IP, and lift pump. (with Holley MightMite[Located in engine comp, his setting is 7psi.])

-Removed entire OEM fuel filter and heater assembly. (That space is where the Holley E-Fuel pump is located)(no filter)

-Did something to governor to “open her up”

-He bought it probably around 06/20, date on title, swears it was driven from here in SC to Florida, NC, etc with no issues... take that with salt and if true assume the issues came from him messing with pumps and governor.

-Brakes are sponges at this point, even though I had the seller bleed the lines because he knew there was air in them. Still garbage.

-Ambulance alternator? He said he put this “brand new, ambulance alternator in. It’s rated at 160A.” (He had to replace the voltage regulator before I could drive it)

-New voltage reg.

-After it stalled on me the first test drive they removed a kink from the fuel supply line and removed all the metal supply lines to the injectors to clean them out because they were “gummed up”. When I arrived back at their shop they tried to turn it over without tightening the lines down and fuel shot all over the engine compartment.
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Check fuel pressure.

Sent from my SM-G988U using Tapatalk
 

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Ford F-350 Super Duty XLT Lariat 7.3L IDI E4OD RWD
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Discussion Starter #3
Alright, so, I’ve made a little headway in the process of elimination but the deed isn’t done.. So I call on you again! So I tested and relocated the Holley pump, because it works and everything was closed yesterday. The pump is just ahead of the FSV and is providing a constant push of fuel. Today I went over to affix the pump to the rail and test drive, below are bullets describing how it went;

•Started right up
•No bucking when put into reverse
•No bucking when in Drive
•Throttle response is still mediocre(cable needs replaced btw)
•Fuel delivery seems fine(Still need OEM filter and separator, 60micron in line though)
•Driving it seems like it’s struggling to shift a little, like it can’t quite get there. Sometimes letting off accelerator helps, sometimes not.
•Drove it for around 20min straight(15-50mph, tried to push it a little so the additives would make it into the nooks and crannies.)
•After 20min it started to buck when getting towards 3rd gear I believe. RPMs built but no shift and bucking.
•Died after about 25min of driving on the way back home.
•Looked under chassis, losing a little oil. •Restarted no problem, died again in reverse.
•Restarted no issue again, started to become sporadic in idle, but drove it home gently.
•Parked in driveway, and let it idle just to watch gauges.
•Became more sporadic, dropping and spiking +/- 400rpm until it finally let go and died.
•Looked under the chassis again and there was a decent puddle of oil (dark dark oil, I think it’s oil atleast...)
•Crawled under to try and pinpoint the leak, the starter is covered in oil and dripping onto driveway.
•Checked oil level, even with the leak it’s still a decent amount over where it should be according to the dipstick.
•Checked trans fluid also, to make sure that wasn’t part of the hesitation in gear shifts, according to dipstick its overfilled also.

A.)Where would that be leaking from?

B.) Would that cause the issues while driving now that I have a constant fuel supply?

C.) Should I drain both Oil and ATF to a normal level? Or, should I just change oil filter, and ATF?

It seems now like the bucking and stalling has something to do with oil pressure possibly. Though the gauges read fine, obviously somethings not right with regards to oil/pressure. Again I thank you immensely for any and all help!
 

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fuel filter on the 50 dollar pump is crap if its not already clogged its about to be. delete that. move further back and put a better filter with a clear port. i have one too. for priming not running. I still run off the lift pump. As for the rest, sounds vacuum pump related to me. especially if you have one of those vacuum manifolds for the transmission. the check valve on the brake booster is probably shot as well. that pump is not supposed to be more than a foot from your fuel tank. it cant pull that much fuel. i guess if you move the pump about a foot away from your tank and below it you may get a better test out of it. also your FSV can be clogged. or misaligned
 

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To delete the filter, just pull it out and put the housing back on without it. If you have the fuel pump where you said, then it'll be fine, because whenever you pull the hose from the tank, you'll get a diesel bath. It'll empty your tank for you. Are your tanks above 1/4? the reason I ask, is because these old Fords have a problem with the in-tank strainer (commonly referred to as the "shower head"). When it breaks off the tank will think it is empty at just about 1/4 tank, and it will shut down, because engine do not run on air alone. Fill them up and see if it runs. You can get a good filter housing from McMaster Carr, they're a little pricey, but they'll work. Just pick on one that you can easily find replacement filters for.
 
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