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Discussion Starter · #1 ·
I have a 97 F350 7.3 with 160,000 miles. Truck was a one owner that I bought from a 85 year old man a little over a year ago. The truck starts up good, idles smooth but once it gets warms, I’ll start hearing a pinging/knock sound coming from the engine. When I go to get on the road the truck has no take off power, makes a loud popping/back fire sound, feels like it’s running really rough but then when I throttle it up from about 40 to 55mph, it goes away and I set my cruise. The truck will get on the interstate if I have the rpm’s up, but if I’m pulling something or taking it easy, truck starts misfiring and jerking until I hit 70 and then I can turn my cruise on. I recently replaced my fuel pump, added oil crossover line kit, new fuel filter, cps, IPR, new tanks and sending units. My old tanks had rust and the lining of the tanks were coming apart. After cleaning the lines and fuel bowl, I still have this problem of it not running right. Does this sound like my injectors are shot? I’ve ran transmission fluid, marvel mystery oil, sea foam in the fuel and put Archoil in the oil, still no fix. Thank you any help
 

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You need to check fuel pressure under load. Stick the gauge out your hood and shut it put it under your wiper blade and see what it does when you’re giving it a good amount of fuel. Other than that I would suspect your injectors may just be tired. You never know if the previous owner kept up with maintenance as well as you are. Also hopefully all of the sensors that you replaced are Motorcraft sensors. The cheap ones have been known to cause many issues
 
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Discussion Starter · #8 ·
You need to check fuel pressure under load. Stick the gauge out your hood and shut it put it under your wiper blade and see what it does when you’re giving it a good amount of fuel. Other than that I would suspect your injectors may just be tired. You never know if the previous owner kept up with maintenance as well as you are. Also hopefully all of the sensors that you replaced are Motorcraft sensors. The cheap ones have been known to cause many issues
What could cause low fuel pressure if that is my problem? I’m thinking it’s dirty injectors because when I do add transmission fluid to my diesel, the truck does run a lot better, but only last a few days and it’s still not running right. If it was a low fuel pressure issue, it just seems like adding ATF to my diesel wouldn’t make a difference.
 

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Most likely your injectors are worn out if you are noticing a difference with the atf.
Fuel pressure could still be an issue.
Just pull them out and send them to unlimited.
They will test them and repair.
Or you could make them bigger, whatever you want to do.
I’d still check fuel press under load before pulling them tho.
 
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Might also look at Rosewood diesel for injectors (rosewooddieselshop.com). Lots of PSN folks recommend them. Swamps has definitely taken a nose dive in the service department since they were sold. Full Force are hit and miss from what I have read.

Cj
 
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Cruss...
I have posted this more than a few times... Something to consider:
"I would recommend that you first invest in FORScan (forscan.org) and a suitable adapter. I have an OBDLink EX usb adapter (should you wish to use a computer to collect data), or take a look at either a BAFX or OBDLink unit. Both BAFX/OBDLink have a bluetooth/Wifi units (there are a few folks around here that recommend them) that will would work with a smart phone (Run of the mill box store scanners and even a great number of the higher end scanners can't touch these trucks as Ford used the "heavy duty diesel" protocol for communication). Once you are setup I would capture data.. At minimum I would save RPM (really this is CPS), ICP, IPR, MAP, EOT and IVS (at least I think that is the PID for the go petal). FORScan will allow you to save the data as a .csv file which you can import into excel. The information you get from the truck will help identify what your problem really is without just "throwing parts" at the truck."
In our older 7.3s there is not as much information available due to the limited number of sensors on the engine (fuel pressure being a big one that is missing). The later 7.3s added additional sensors to help with the engine management. FORScan will allow you to run a buzz test (KOEO) and a cylinder contribution test (warmed up engine KOER) on the injectors. Both are a pass/fail sort of test, but will generate codes if something is not right with the injectors (I have read that Fords scan tool can actually report back the percentages on the cylinder contribution test).

Cj
 

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I agree.
For the price of an adapter and app on your phone, it’s well worth it
 
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