What is causing the 7.3 to run like this

Centurion_guy

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Ok I need some advice about my 7.3. After driving the truck from Joplin to Springfield yesterday the truck seemed to want to die as I pulled into a parking lot. I pushed in the clutch and the truck barely idled. Then out of no where it went to a high idle and then smoothed out. It threw a code but when we plugged in a Pegasus tool to read the truck began idling bad again for just a second or two and we couldn't communicate. Now anytime I spin the motor above 2300 rpm it seems like it has a miss fire or a limiter and doesn't want to pull anymore. But it ran well enough to get us home. Any help would be appreciated. This is my first diesel and my back ground is in mustang. I don't know how else to describe what it is doing. I went ahead and did a fuel filter because I didn't know what could be causing it. While I was there I check fuel pressure with a tire gauge (I know I am a dummy) and it had about 54 psi at idle.
 

superpsd

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Need a scan tool. I use an Android device with Torque Pro and Car Gauge Pro with Bluetooth OBDlink LX unit. Or throw a cheap CPS at it. Motorcraft are like 25$.
 

Centurion_guy

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New development

Alright. So the check engine light has been on and off for the past week since I had my first problem with it wanting to die. It has been lately where the injectors will get loud and the truck will shake. But every now and then they quiet down and it runs smooth as silk. I was able to pull the codes and watch the live data today. P1211 and p1212. There is a little oil in the icp. The previous owner had an edge ez in the truck when I bought it and I believe the old edge works buy fooling the icp to turn up. What do you guys think the best route would be to fix this?
 

rrchlin

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I have no knowledge of some of these 7.3/diesel specific parts, but check the fuel pressure.

My truck ran great til about 40mph and it would shift and drop to 1200rpm and wouldn't pull until it crept to 50mph. Then run fine. But even then there was a huge power drop off but only obviously noticeable/troublesome if you were racing.

I only noticed something was seriously wrong after trying to catch up with a Chevy 6.5 and couldn't pull on him or keep up at all.

I drove like this for about 6 weeks until checking my fuel pressure and finding it had 0-PSI on 2 different guages. Another member in the "runs like crap" thread suggested a vacuum guage to check for a clog before replacing the pump.

I didn't have a problem with missing/shaking until letting the truck sit for 2 weeks. And when I started it then, I definitely had some missing/shaking/no power until warm.

The HF pump fuel tester is about $15 and worth a check.
 

old man dave

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Alright. So the check engine light has been on and off for the past week since I had my first problem with it wanting to die. It has been lately where the injectors will get loud and the truck will shake. But every now and then they quiet down and it runs smooth as silk. I was able to pull the codes and watch the live data today. P1211 and p1212. There is a little oil in the icp. The previous owner had an edge ez in the truck when I bought it and I believe the old edge works buy fooling the icp to turn up. What do you guys think the best route would be to fix this?

Try removing the Edge and eliminate that as a cause.

Also on the fuel filter canister there is a Schrader valve (looks like a tire valve stem) where you can use an ordinary tire pressure gauge to measure fuel pressure. Use a cheap one as the diesel fuel may not agree with the innards of the pressure gauge. Also be aware that fuel may spray out when taking the pressure. Shroud the valve with a rag to avoid getting diesel in the face.
 
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rrchlin

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Also on the fuel filter canister there is a Schrader valve (looks like a tire valve stem)

If you have an option, use a 120 PSI guage over a 50psi guage. Fuel pressure at idle is supposed to be 60psi. I've launched the cheap guages innards across the street trying to check PSI on load range E tires lol.
 

Centurion_guy

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I checked the fuel pressure with a gauge that can read 80 psi and I am seeing about about 54-56 psi. I have been asking around and I am hearing the edge may be apart of the problem. I had someone e tell me the codes I had seen were generic codes for low hpop pressure. What do you guys think. I just replaced the fuel filter as a hopeful shot in the dark and it didn't help
 

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