7.3 help.
Thread Starter
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5th Wheeling
Joined: Aug 2022
Posts: 33
Likes: 2
After i do the buzz test it says this on all the cylinders.
Lead Driver
Joined: Jul 2017
Posts: 6,862
Likes: 2,335
From: WV
Originally Posted by Muteme87
When I had it dead headed it ran for a 1 min. I wouldn't say fine it ran like 2 coil packs off a v8 then just sputtered out. And it didn't start back up like that.
Originally Posted by Muteme87
I already replaced the injector computer. I really don't want to replace a good pcm but I'm running out of options.
Lead Driver
Joined: Oct 2005
Posts: 6,129
Likes: 1,919
From: Ponca City, OK
Ok there is way to much going on all at once to get any kind of definitive diagnostics. I got a few questions to be sure I fully understand where we're at. Where did you connect the gauge for the fuel pressure test? Have you removed the fuel bowl lid recently? Is that ICP graph above taken while you had/have the ICP/pressure sensor in the head disconnected? If the sensor was disconnected then that reading is a phantom, a preset number generated by the PCM and we have no idea what the hpo is doing. We really do need a gauge pressure reading on the fuel. The simple quick and dirty, approved method is to connect you test hose to the drain valve port and open the valve(w/ good tight clamps of course). Now if you've had the bowl open recently are you 100% sure the stand pipe(black tube the filter slides over) was in straight and fully seated when the lid was reinstalled? There is a check valve of sorts in the bottom that prevents fuel going to the heads if it's not properly installed. It's to prevent unfiltered fuel from getting to the injectors.
Thread Starter
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5th Wheeling
Joined: Aug 2022
Posts: 33
Likes: 2
Ok there is way to much going on all at once to get any kind of definitive diagnostics. I got a few questions to be sure I fully understand where we're at. Where did you connect the gauge for the fuel pressure test? Have you removed the fuel bowl lid recently? Is that ICP graph above taken while you had/have the ICP/pressure sensor in the head disconnected? If the sensor was disconnected then that reading is a phantom, a preset number generated by the PCM and we have no idea what the hpo is doing. We really do need a gauge pressure reading on the fuel. The simple quick and dirty, approved method is to connect you test hose to the drain valve port and open the valve(w/ good tight clamps of course). Now if you've had the bowl open recently are you 100% sure the stand pipe(black tube the filter slides over) was in straight and fully seated when the lid was reinstalled? There is a check valve of sorts in the bottom that prevents fuel going to the heads if it's not properly installed. It's to prevent unfiltered fuel from getting to the injectors.
2. Yes I have removed the fuel lid a few times. It's always full.
3. The icp was unplugged from the head aways. You made a good point. I will plug it in and get a new reading.
4. I'm going to check the fuel pressure the way you said. But I well say when I open the fuel release valve fuel shoots out like a fire hose so I believe pressure would at least be good enough to start it.
5. The fuel filter dummy cut off. I have removed everything in the tube. So that shouldn't be active anymore. Fuel bowl heater is also disconnected.
Thank you for taking your time to help. And far as taking it to a diesel mechanic we have 2 in my town neither work on the 7.3. I would have to tow it an hour towards Dallas.
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,355
Likes: 5,947
From: Lake Hartwell, GA
Even if you removed the standpipe guts in the fuel bowl, there are slots that need to be lined up in order for fuel to flow from the bowl to the heads. We have seen this specific no start condition only a couple of times.
I only read the last few posts so forgive me if this has been stated.
I only read the last few posts so forgive me if this has been stated.
FTE Leadership Emeritus
Joined: May 2014
Posts: 27,355
Likes: 5,947
From: Lake Hartwell, GA
Thread Starter
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5th Wheeling
Joined: Aug 2022
Posts: 33
Likes: 2
Ok there is way to much going on all at once to get any kind of definitive diagnostics. I got a few questions to be sure I fully understand where we're at. Where did you connect the gauge for the fuel pressure test? Have you removed the fuel bowl lid recently? Is that ICP graph above taken while you had/have the ICP/pressure sensor in the head disconnected? If the sensor was disconnected then that reading is a phantom, a preset number generated by the PCM and we have no idea what the hpo is doing. We really do need a gauge pressure reading on the fuel. The simple quick and dirty, approved method is to connect you test hose to the drain valve port and open the valve(w/ good tight clamps of course). Now if you've had the bowl open recently are you 100% sure the stand pipe(black tube the filter slides over) was in straight and fully seated when the lid was reinstalled? There is a check valve of sorts in the bottom that prevents fuel going to the heads if it's not properly installed. It's to prevent unfiltered fuel from getting to the injectors.
Ok this is with pressure sensor plugged in the head. Im not sure how to read this bc it says x1000?. But if i only have 153 psi in my hpop its bad right?
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Thread Starter
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5th Wheeling
Joined: Aug 2022
Posts: 33
Likes: 2
I just looked at the ipr and it looks new like someone replaced it. The big nut holding it in I was able to turn with my hand. Do you think that nut not being fully tight would stop it from working? It's on there as tight as you could do it by hand.
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5th Wheeling
Joined: Aug 2022
Posts: 33
Likes: 2
Ok check it out. I unplugged the ipr and plugged it back i open my hpop gauge and cranked it and the psi jumped real Hugh and almost started then the psi dropped all in a split second.
Cargo Master
Joined: Apr 2022
Posts: 3,201
Likes: 1,704
No it won't stop it from running just being loose. It just hold the electro magnet part on. Could still be a bad ipr especially if it isn't a Motorcraft oem one. Lot of people keep a spare one. Be nice if somebody close by you had one you could stick in it to try vs buying a new one.
Cargo Master
Joined: Apr 2022
Posts: 3,201
Likes: 1,704
Acting like a sticking ipr valve to me. I'd put my money on ipr valve.
Thread Starter
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5th Wheeling
Joined: Aug 2022
Posts: 33
Likes: 2
No it won't stop it from running just being loose. It just hold the electro magnet part on. Could still be a bad ipr especially if it isn't a Motorcraft oem one. Lot of people keep a spare one. Be nice if somebody close by you had one you could stick in it to try vs buying a new one.
should I replace the steam as well?