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02 F350 7.3 No Power Under Load Uphill- FORD Scanned-Can't Find Problem- HELP!!

24K views 87 replies 20 participants last post by  Markq 
#1 ·
I have a 2002 7.3 with auto trans that I bought new- I have babied it and taken impeccable care of it- it only has 112,000 miles- the transmission was replaced by Ford at 93,000 miles- I have used it in the past to tow large trailers nd I know what an impressive work horse it is....I know how it feels when it is running right under a load- last summer when pulling my 5000lb camper to the mountains I noticed a loss of power when going up a hill, didn't want to downshift, no power- took it to my mechanic and he found that there was a split in the hot side intercooler CAC boot- we were sure that was the problem, and it was fixed. They had scanned everything, no codes. It seemed to be running fine and towing well but at the time was only towing on the desert floor- that was the last time I pulled my trailer into the mountains for the season- I stayed on the desert floor during the cooler months and my truck seemed to tow fine, thought the problem was resolved. I pulled my camper into the mountains this past weekend and noticed when going up an incline it would begin to slow down and when I depressed the pedal to get it to drop into a lower gear, there was no further throttle response- I would get to about 55 mph at 22000 RPM"s and my foot was on the floor- no lights lit up on the dash- engine temp and trans temp did not move...this is not right. It seems to be running smooth without a load...idling smooth...no chugging sputtering or stalling- it's just with a load that it is no longer downshifting and pulling with lots of pedal to spare...what happened?? It is all stock except for a Donaldson Blue 6637 air filter- I have never had any problems with it aside from a new transmission from ford at 93,000 miles- the one thing that makes me a bit suspicious is 5000 miles ago I had the fuel filter replaced because I smelled diesel fuel....the filter was pretty dirty and diesel was seeping out from around the gasket even though the lid was secure....the drain valve was completely blocked even though it had been changed 12,000 miles earlier....at the time I couldn't understand how the filter could get so gummed up because I am religious about changing the filter by the manufacturer specs....and why would the drain valve be completely plugged(Nothing came out when opened) when it was leaking and replaced only 12000 miles before?? I stopped by my mechanic and relayed the whole story to him- they had no immediate thoughts, it's just going to be a witch hunt, he's going to scan it but can't get me in until next week....so have to drop the truck off for an indefinite amount of time so they could trouble shoot....he is supposed to be a 7.3 diesel expert and he didn't seem interested in discussing the possibilities....I felt a little brushed off- I am pretty upset over my truck not running right and was hoping to receive a little reassurance that this is a problem that he has seen before. I take impeccable care of my truck and was hoping that maybe people on this forum could give me some suggestions or stories if they have experienced something similar. Would appreciate any input!
 
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#54 ·
I would suggest a permanent fuel gauge on any 7.3 or 6.0 is a plus

1826714C2 check fitting in the head may be worn and not letting fuel into the injectors
 
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#59 ·
Would like to see 50 psi at all times on a 7.3 -- but it kinda depends on where the reading was taken from -- you need to use the port just to the right and below the yellow drain lever
 
#60 ·
Yes, that is where the reading was taken....and it was 4 PSI below 50....so just to rule out a fuel pump issue we changed it out....aside from a new transmission, my truck has never had any issue....so all the parts are original....so even though this process includes installing some parts that do not fix the problem....I believe at this point it is a process of elimination...after 18 years, I'm ok with changing out original parts to new parts before they fail....
 
#61 ·
Would be good to check fuel flow at the heads and take a look at the fitting I posted a few posts up

Do you get black smoke when you are pulling up a hill with the trailer?
 
#62 ·
I did see you mention that fitting....what do they "Call" that fitting....what is it's name??

Nope, no smoke of any kind from my truck...very clean burning...maybe sight smoke whn I first start it up....and maye a puff of smoke when I punch it...but no visible smoke at all when towing....
 
#64 ·
That is a check valve to help keep pulsations out of the fuel going into the injectors
 
#65 ·
OK....thats a new one to me....so I will certainly check on that one....thank you!!
 
#70 ·
Thanks for the suggestion....so you are saying that sometimes the MAP sensor can be bad but not show up when it is scanned?? Is it common for a sensor to be failing but not show on the scanner? Are there any other sensors that could be linked to these issues and not throw a code?? I left a bag of Motorcraft parts with the mechanic...EBP sensor and tube...IPR...CPS....he didn't think that would help since he didn't get a code.....I told him to change them anyway....I guess the MAP sensor is the next part to change....Thanks again for your input
 
#71 ·
First, check the mechanics of the system (is the hose in good condition and connected) not sure of codes but if the vacuum line is compromised it wouldn't show a code it just will run like crap... I left it off once and it ran but had no power since the pcm wouldn't give it any more fuel since it didn't see any boost
 
#76 ·
I did have the fuel lines blown out and the strainer cleaned between the fuel bowl and the IPR....I am not sure that I am aware of this other strainer that you were talking about....I will ask my mechanic....the dual screens in the old sending unit in the tank was clean(new sending unit installed)...the fuel filter that was changed out was fairly clean/....and the screen between the fuel bowl and the IPR was pretty clean when it was all checked.....
 
#77 ·
He is talking about the fuel fitting that screws into the heads -- where the fuel line connects
fuel pressure would be best tested at the heads to eliminate any upstream restrictions

Some of the CPS can cause an engine to run poorly -- they are pretty cheap, so changing that out may make a difference

No power with no smoke, means you are not using fuel, fuel = black smoke
also, lack of injection oil pressure can cause the same effect
commanded fuel pulse vs actual fuel pulse should tell the story
not sure what your mechanic is testing
one of the issues with 7.3 injectors is the poppet valve wearing over time and not fully opening
this can be "fixed" with a shim kit or new injectors
 
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#78 · (Edited)
Thanks hydro...

I made a copy of these 2 latest posts and will ask the mechanic when I talk to him in a little while.....he is installing an Adrenaline HPOP today....so yes, no power, no smoke.... at this point the mechanic feels that a lack of injection oil pressure is the issue....not sure exactly what type of reading you would get with those ford scanners....but it didn't show anything in absolute failure mode to indicate a clear cut problem....but I assume since we have addressed the main areas of lack of fuel delivery FIRST, he feels that the next thing would be the HPOP....and I believe he feels if the issue still persists he will want to install new injectors- I posted my issue on here because this was clear it was going to be a pain in the butt to figure out, so I was looking for input from other ford people- can never have too much input when it comes to an elusive problem like this in my opinion......I know some people have suggested I take my truck elsewhere, but this guy is the Powerstroke guru in Tucson area and his own personal truck is a 2000 7.3, which is 2 years OLDER than mine..- I have been going to this mechanic for years- he is a friend of the family and was a diesel guy for Ford for 20 years before he went out on his own...so even though this is a little bit of a witch hunt, I trust that he is really doing his very best to find the problem here....in a few of the fixes up until this point he has just charged me his cost of the part....hasn't even charged me labor....so I truly believe he is doing his best. Thanks for the input...as soon as I get to the bottom of this I will be posting the resolution for sure!!
 
#80 ·
PROBLEM SOLVED!!
Just wanted everyone to know that I finally got to the bottom of this horrible elusive nightmare of low power when towing small travel trailer uphill- Please click here for recap of problem-


As indicated in earlier posts, this issue had everyone scratching their head- the truck ran clean, smooth and beautiful until I hooked up my 5,000 lb travel trailer- it would pull fine until I got to some sort of a grade- then it was a complete dog- 55 mph at 2200 rpm's was it and my floor was on the floor- overdrive OFF- this truck was scanned by FORD and here were no codes- all values were within normal ranges, with and without towing my TT....we replaced the entire sending unit by my request even though screens were clean and tank was clean, then moved on to new fuel filter- no improvement- I ordered some Motorcraft sensors online- even though there were no codes for any of them failing my thoughts were that even though this truck only has 113,000 miles on it it still is an 02, 18 years old- so I wanted to change things out to new to cover all bases- new IPR, new EBP and tube, new CPS- even though the truck felt a little snappier and crisp after sensor replacement the low power issue under load still remined, then my Ford guy installed an ADRENALINE HPOP....holy crap, problem solved....I heard that old familiar roar under the hood when accelerating, better throttle response and GREAT power when towing uphill- the weak stock HPOP issue was present long before I realized there was a problem because that power roar had diminished over time as did the power- it was so subtle I never noticed it until the HPOP was changed out- even though the stock HPOP was weak there was no code and the reading was within normal range....one hiccup was that I had my check engine light come on the first time I towed afterward and it ended up being code 1211....which is the ICP sensor- I was told that this is common after the Adrenaline HPOP install....so a new updated ICP sensor was installed and everything seems great....just wanted to share this update with everyone- and also tell everyone that in my experience just because you get NO CODES does not mean there is no problem- many mechanics rely too heavily on CODES, sometimes it is a complete witch hunt, which was the case for me- thank God I have a very patient mechanic who just kept pecking at it, with no help from from any type of scanning device, he just relied on his experience with diesel engines and the "What's Next" theory- Thank you everyone for all your suggestions and input- hopes this helps someone that experiences the same problem as I had!!
 
#83 ·
Glad the truck is running again

While I agree that sometimes the computers are thought to be the magic fix, when indeed they are just a tool -- The remaining P1211 code tells the original problem still existed
Low power can be caused by low fuel injection pressures, which the P1211 code represents
A high pressure leak or weak pump or bad ICP or laggy IPR or a poor connection to the PCM would be the culprits
Checking for codes is only part of the process, one must also monitor pressures as the engine is operated
Not only pressures, but more importantly voltages -- the PCM will substitute an inferred or made up number if the reading from a sensor is out of range -- casual reading of pressures will give a false flag and cause one to skip over a potential problem
Reading of voltages from the sensors is always accurate -- if this had been done earlier in this story, the outcome would have been shorter and less expensive
It should have been noted that the voltage from the ICP sensor was not the same as the pressure reading -- this is a quick clue that inferred numbers are being used, and not to trust pressure readings
The PCM should have thrown a code, but the 7.3 system may be more tolerant(larger fault window) than the later systems -- either way the voltage and pressure readings would be misaligned
 
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