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2002 f350 Help

5K views 34 replies 5 participants last post by  73Diesel 
#1 · (Edited)
Hi everyone,
im new to the site but have read the threads here before looking for advice. Here's my problem. I have a 2002 F350 7.3L crew cab. It has a K&N intake, 4" downtube and exhaust, fuel tank mod and pre-pump filter installed and a TS Performance 6-Position chip. I installed the chip about 8 months ago and it was awesome. But for the last 2 months or so it seems to have lost power on all the tunes. Basically the 120hp tune feels more like a stock engine and if i put it on the stock setting it has little or no power. It still accelerates on the stock setting but is slow to do it. On 120hp setting it will still blow a little black smoke but nothing like it did when i first installed the chip. I did notice the ICP sensor has a little fuel in the plug so i know thats not good and i need to replace it but im asking if that sounds like my problem? or is it something else.


I know its a lot of reading but i trid to remember everything i could about what the truck is doing. If you have any other questions let me know. Thanks for the help in advance.

EDIT: Forgot to add that i have aftermarket gauges and the fuel pressure holds right around 68-70 psi. I changed the frame fuel pump about 2 months ago also but my problem started before the new pump. This new pump is louder than the stock one and it sounds like it revs up and down. I have read about IRP sensor also. Just looking for advice on where to look.
 
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#2 ·
Fuel filter, water seperator?
 
#3 ·
Do you have gauges installed? Any idea what boost numbers you are seeing?
 
#6 ·
20-22psi seems a little low for a 120 tune. I'm getting 17 stock. You might re-check your numbers and check for boost leaks and the condition of your turbo
 
#7 ·
I have gone through all of the turbo hoses already and havent found any leaks. I only say 20-22 because thats as far as i remember and all i would push it. Maybe it went to 24psi. I have heard that you shouldnt take the stock turbo to more than 25psi but im not sure. The truck spools up and still pulls really hard. It just used to pull a lot harder when i first got the chip. And like i said it wont do anything on the stock tune. I was leaning more toward a fuel issue than an air issue.But im no expert. Im very handy around the shop and have been restoring origional ford bronco's for 15 years. So im not too shy when it comes to anything.
 
#9 ·
Try putting it in stock and see what max boost is. It shouldn't blow smoke unless the boost is real low.
There is a lot of discussion about the K&N filter and dust ingestion. Anything that gets past the filter gets to hit a compressor going 100,000 rpm's. It's like throwing gravel in a blender. If you pull the intake tube and look at the fins, they should be clean and sharp, not like they have been sandblasted.

As far as it being a fuel issue, it's possible. You would need to get a pressure check on it.
 
#10 ·
i was reading about the K&N filters. I will pull the tube off tomorrow and look. Like i said the fuel pressure to the HPOP is 68-70psi. And they hold pretty steady. But I can look into getting a second guage to put under the hood to confirm. Right now the aftermarket fuel pressure sending unit is located on the back/driver side of the fuel bowl. Is that the recomended or best spot for it?
 
#11 ·
I believe the drivers side plug is pre-filter pressure. If you go to the passenger side rear, down a little lower, you can get post filter pressure. Not only is it post filter, but post check valve at the filter, which can be a baffling restriction to fuel pressure at times.
If you are holding 70psi on the fuel pressure, and it is still 70psi post filter, then fuel isn't the problem
 
#13 ·
Not the IPR. That's the hp oil system. The black stem that the fuel filter goes on is a checkvalve that can restrict fuel to the injectors, normally getting fouled by it's own o-rings. There is also a checkvalve on both fuel lines as they enter the heads.
 
#15 ·
That's correct. The 2 metal lines coming out the bottom passenger side of the filter are the fuel lines to the heads. The 2 metal lines on the drivers side are the supply (low-rear) and return (top front). The 2 rubber lines are the hp oil lines to each head. Yes, they can be cleaned up or replaced, but takes a special disconnect fork. If you search around in the FAQ section it tells you how to fabricate one. I would go the Simple Purple cleaner route since those lines are about $100 a pop.
 
#17 ·
Simple Purple is a cleaner that works good for de-gunking the engine
 
#19 ·
Yes, same stuff as Purple Power. I cover the alt and use a low pressure setting on the power washer.
You remove the checkvalve from inside the filter assembly. Again, I wouldn't just pull it to pull it, but just remember it's there should you ever have an issue.
 
#20 ·
RT or KLhansen has a link to Guzzle's page that get's into rebuilding the filter assembly.
 
#21 ·
Ok. I guess ill do what you suggested and remove and clean the check valve in the filter assembly and clean the metal fuel lines going to the heads. at least its a place to start since I am clueless to why the truck runs fine but just isnt running like its on 120hp tune.
 
#22 ·
If you move the pressure sender to the other port first and it keeps the 70psi, it isn't fuel.
I would look at the turbo and look at the EBP sensor and tube as well. Make sure it doesn't have a hole in the tube or is plugged up.
The turbo has 2 sides to look at. If you have an exhaust leak, it will affect it just as much as an intake leak. The exhaust donuts are good for leaking and a pain to get to.
 
#23 ·
I hate to sound like I dont know what im talking about. But "Exhaust Donuts". As far as i remember my exhaust has the V-Band clamp at the turbo holding on the down tube and then a U-Clamp to bolt it to the short section before it dumps out before the passenger rear tire.
 
#27 ·
Not only look for a clog, but ensure there isn't a hole in the tube. Try spraying some brake cleaner down the tube and look for it coming out.
 
#28 ·
I didnt have time to work on the truck tonight. I will try tomorrow. I did run the truck on the stock setting and it will boost to 15-16 but it takes a bit to get there maybe 1/8 mile or better. It feels like the boost isnt building fast enough or there isnt fuel there to get the motor RPM's up.
 
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