Hi, I have an 02 f350 7.3 with 144k, and it runs generally well most of the time, except after longer hauls of anywhere from 2-4 highway hours, at which time I experience a noticible loss of power. Each time this happens and I let it sit overnight, its power and snap will be back. Despite the relatively low mileage, could this be the early signs of impending hpop/injector failure? Or icp and ipr related. I have an aftermarket air filter and 4” exhaust, and I use SCT’s ‘economy’ tune. Its pretty frustrating since I’d like to tow a camper for a 5-6 hr trip, but I know by the end of it I’ll feel like I’m towing with a chevy s10. Any insight would be appreciated!

 

Have you done the hutch mod to the fuel tank? If your fuel pickup is clogged you could get these symptoms. Do you have scanning capabilities? If you could monitor your sensors while this is happening it could provide you with needed information.

 

I haven’t done the hutch mod, but I do have a fuel pressure gauge, I think I installed it in the bowl pre-filter; in any case it shows generally 60-68psi pressure, and it dips lowest to maybe 55psi if I’m flooring it. I read somewhere that those pressures will naturally read lower if I install the sensor in a different bowl port. The data reader on the SCT is pretty chintzy but I think I can trust the oil temp and inj pressure psi. How involved is that hutch mod? Sounds fun.

 

You can search it and find all kinds of info on it. You can either drop the tank or pull the bed back and pull the fuel intake and modify it. If you have fuel pressure I doubt that that is causing your problem at the moment. Get yourself ForScan and an OBDII adapter and you can read your other sensors and the IPR. When the IPR goes it seems to first show symptoms when hot. You can try cooling the IPR with canned air or ice water when your symptoms show and see if that's the problem.

 

Doesn't sound like fuel pressure is the problem but that is good you keep an eye on that. Yes I agree with Walleye that you need to get better antiquated with the ICP and IPR readings before suspecting a high pressure oil problem. You will have to unplug the SCT and plug in an OBD Link dongle or cord and run a program like FORScan or Torque Pro to see that. Or my personal favorite is the Edge CTS Insight. Very easy to set up and gives you a more permanent way to see all your important sensors in one slick little display that plugs into the OBD port and suction-cups to the windshield.

 

One thing I'd like to add, may be a moot point on your problem tho. Fuel pressure gauge, it's a good thing to have, but you need it on the passenger side port by the drain valve. Royal PITA to to remove the fuel bowl just to get it on that port vs the easily accesible one, but then you have post filter pressure vs pre filter, post pump.

On mine with a new Motorcraft fuel filter i was seeing pressure drops post filter during heavy tow grade climbs that i wasn't seeing pre filter. Went from seeing a constant 56psi to 49psi during those pulls. Changed out my FRx spring for a few more psi and those pressure drops are gone now usually at 62psi, sometimes dips to 59 on long grades. As the fuel filter clogs up before change intervals the pressure is likely to dip farther, thought all was good before i moved the sensor.

 

What engine oil are you running?

 

I'm with Dan. Engine oil type, oil level, and miles since last change?

 

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