Hi,

I am new here my 99 7.3 with 205k has been losing power going uphills. I live in the mountains and need to get my truck back from Denver so I need help asap.

This started recently and has seemed to be getting worse over the course of 200 mi. It is not noticable on flat ground unless you really get on it on the highway butt it sounds like a fuel problem to me. Possibly a bad Cam position sensor, crank pos sensor, clogged mixing chamber screens, clogged cat or ever the tranny/ torque converter going bad.

Has anyone else here had similar situation and what should I start with? Any help is much appreciated thanks

 

Have any gauges? Can you hear the turbo at all? Possible boost leak or uppipe leak. Air filter clean? When is the last time the oil/fuel filter was changed? Start there and see what you come up with.

 

Hi Monte, welcome to the 7.3 side of FTE. I thonk you need to find out what your fuel pressure is. Pick up an adapter setup from Guzzle in Greeley. that wat you can use any fuel pressure guage. you need to see 55-65 at WOT. any less than that and she won't be right. I fought a similar problem from MO to CO and spent way too much time chasing my tail to only find out I had a plugged filter. Could be screens in the tank, inlet screens in the fuel pump, bad fuel filter, or screens in the fittings on the fuel lines at the heads. don't assume that just cause you changed the filter its OK. or it has pressure at idle, so its OK.
link to Guzzles sitehttp://www.dieselorings.com/index.php?page=browse&action=list&group=6&cat=18&o rderby=DESCRIPTION

Barney

 

x2..................check your fuel filter first....Have you done the fuel tank mods???..if not maybe try blowing back through the fuel tank...

And welcome to FTE

 

thanks guys,

I have only had it for a month and a half and I changed the oil, fuel filter and put on a new cam position sensor. No mods. The air filter looks very new.

I didnt mention that once it gets triped up it will run rough until I stop and take it out of Drive but sometimes it resets automatically when Im at a slow speed.

Could it be an injector going out and then resetting?

 

I was seeing the exact same kind of symptoms several weeks back and found it to be a partially plugged fuel filter screen in the fuel line between the tank and my pump. Cost me absolutely nothing to remove and clean the small screen and she's running great again. If neither you nor a previous owner have done the in-tank mods, you won't have the screen I am talking about, and there are only two places ahead of your fuel filter which can plug... the screen in the bottom of the pickup foot inside the tank and the check valve on the fuel pump.

 

had it hooked up to a scanner it it has a low boost code as well as incorrect ratio for 2nd gear. Sounds like a turbo problem? possibly still a fuel problem?

 

Sounds like fuel to me too. The screens in the mixing chamber are the most common culprit.

 

7.3L FUEL SYSTEM CONCERN. - YouTube

 

So I ended up bringing it to the dealership to diagnose it and told them what I thought it could be including the clogged fuel screens. In the end they told me the low boost was due to major exhaust leaks in several spots. I fixed the leaks and still had the problem so then dropped the tank and discovered that the mixing screens looked completely clogged. The part that gets me is the dealership ruled out the posibility of the clogged mixing screens saying that the fuel pressure tested just fine, whcih cost me the money to diagnose and fix a problem that might not have been worth fixing at the time

 

Ah, but did they volume test the fuel pump? What a bunch of dimwits at dealerships.

 

an easy test for restriction in the tank is to install a vacuum guage between the pump and the tank. If I remember correctly, Ford says anything more that 6in of vacuum at IDLE indicates a plugged screen or restriction. I've never seen a number for WOT.
still say the best way to test it is to put a guage on it and drive it. a plugged filter will show its ugly head right away.

Barney

 

Monte721, these guys on here have been threw most problems your ever going to find on7.3L diesels. Barney is right on the gauge. And for the record, you won't make boost if you don't have fuel going to the cyclinders. Lesson learned and on to the next one.

Chet

 

Check the clap on your turbo all ford puts on there is a hose clamp and they will come loose causing you to loose the air flow

 

I hope it didn't hurt too bad. Sounds like you learned an expensive lesson. Dealerships are good at taking your money. Sometimes, if you get a really good diesel tech, they can fix things too. Otherwise they hook it up to a computer and read your odometer and provide you with an estimate based on codes and mileage.