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Discussion Starter #1
I have a 97 PSD with around 75K miles that runs a little rough which is really only noticeable towing my 8000# camper. It's almost like it may be running on 7 cylinders.

Things I've done recently are; oil change, fuel filter, new IPR. None of this has made a difference. I took it in to a local diesel shop who did a cylinder contribution test and checked for any codes from the computer. These both checked out good. I know the mechanic thinks that I'm imagining this, but he also didn't have a load on it when he did his road test. Again, it is really only noticeable when the engine is being loaded.

To make matters worse, we leave later this week for Florida with the camper.

Any ideas are appreciated.

Thanks,
Steve
 

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Blocked EBPV or restricted kitty?
 

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Discussion Starter #4
Thanks guys for the ideas.

I already unhooked the connector to the EBPV and let's just say that I know there is no restriction in the cat. I also did the FPR Shim recently, but don't actually know how much pressure I'm getting. I guess I'll need to verify it with a gauge. I assume they make gauges that can stay connected or thread onto the schrader valve? Can you get that at a parts store?

If I find the fuel pressure is low, are we just talking about a new fuel pump, or is there potentially something else? If I find the fuel pressure is OK, then what?

Thanks,
Steve
 

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I have a 97 PSD with around 75K miles that runs a little rough which is really only noticeable towing my 8000# camper. It's almost like it may be running on 7 cylinders.

Things I've done recently are; oil change, fuel filter, new IPR. None of this has made a difference. I took it in to a local diesel shop who did a cylinder contribution test and checked for any codes from the computer. These both checked out good. I know the mechanic thinks that I'm imagining this, but he also didn't have a load on it when he did his road test. Again, it is really only noticeable when the engine is being loaded.

To make matters worse, we leave later this week for Florida with the camper.

Any ideas are appreciated.

Thanks,
Steve
Steve, My '95 and my dad's 2000 are doing the same thing it sounds like. No codes and passes all tests but just isn't running right. If I pull anything other than an empty trailer, I have no power at all. Seems like I am running on a 4 cylinder. My fuel pressure is at 65PSI, no cat, and EBPV cleaned and reading fine. Both of our trucks sound the same, rough.. I think, but don't know, that the ULSD is the problem and causing premature failure of the Injector O-rings. That is my next step, changing the injectors and orings.
 

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Discussion Starter #6
Rowdy,
We just got back from Florida last night, so this is my first chance to check the forum in about 10 days.

Sounds like our problems are similar, but I wouldn't say mine feels like a 4 cylinder, more like a 7 cylinder. It can still pull the hills in 5th gear, except for the steepest ones. But, it still is off a little. Feels like it's chugging. My wife even noticed it when we were sitting at a stoplight. The stick was shaking like mad and she made a comment. Was like that for the whole week. Then one single time on the way home at another stoplight it smoothed out for about 10 seconds, to the point where it felt like it wasn't even running. Have never felt it that smooth. Went right back to its old ways though.

I'm also thinking about changing the injector o-rings. Or, I might just sell it and go with something newer. Am thinking about a '02 or '03 with the 7.3.

Steve
 

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Rowdy,
We just got back from Florida last night, so this is my first chance to check the forum in about 10 days.

Sounds like our problems are similar, but I wouldn't say mine feels like a 4 cylinder, more like a 7 cylinder. It can still pull the hills in 5th gear, except for the steepest ones. But, it still is off a little. Feels like it's chugging. My wife even noticed it when we were sitting at a stoplight. The stick was shaking like mad and she made a comment. Was like that for the whole week. Then one single time on the way home at another stoplight it smoothed out for about 10 seconds, to the point where it felt like it wasn't even running. Have never felt it that smooth. Went right back to its old ways though.

I'm also thinking about changing the injector o-rings. Or, I might just sell it and go with something newer. Am thinking about a '02 or '03 with the 7.3.

Steve
Steve,
I am going to try changing the fuel lines from the pump to the filter with the expensive Ford ones. Right now I just have regular rubber fuel lines. They have worked before, but maybe these just are not stiff enough and are choking he engine for fuel. If that doesn't work, I am just going to change all eight injectors and say some prayers hoping it works. I will let you know. It will be next weekend at the earliest before I change the injectors.

Joe
 

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Discussion Starter #8
Joe,
One of the previous posters above suggested a low fuel pressure possibility as well. When I changed the IPR a few weeks ago, while we had the fuel bowl moved out of the way it seemed like a good time to change the flexible fuel lines too. I just went to NAPA and put on what they had, not the Ford ones you are refering to. I hope the ones I used won't be a problem, but this rough running started months ago, and can even be felt at idle so I don't think that is my truck's problem. I'll still check the fuel pressure, I just haven't gotten to that yet. I think I'm going to pull the valve covers and start it and see if one of the injectors is not spitting oil properly, and probably change the o-rings. I doubt that I'll go throught he expense of replacing the injectors since my ultimate goal is to upgrade to a newer model.

Steve
 

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Have you tried unplugging the ICP ?....

While you are there ,,see if the sensor is leaking oil....
 

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Steve,

I would love to upgrade to a new model, but I just upgraded my wife to a new F-150, so it will be a while before I upgrade. So I have to get mine running right again, plus I really like my truck except for the fact that it is just an Extended Cab. Wish it was a Crew Cab, but couldn't complain on the price and miles when I bought it about 10 years ago. I doubt the fuel lines are my rough running problem, but may be my pulling problem, "may" being the key word there. I will update by next Friday if the injectors fix the roughness. I have a mechanic that is going to change the Drivers side and I will be changing the Passenger side at the same time and learn how to do it properly.
 

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Steve,

Changed the injectors yesterday and went with the RDS Stage 1's that I bought from DPPPower.com. Well, it didn't fix the problem, just made it more noticable. Luckily the mechanic that was helping me had a spare IDM that happened to be for my model. I swapped it out and TA DA!! Ran smooth as a kitten. Got my IDM ordered. Got mine for $325 from Auto and Heavy Duty Computer supply - ecm ecu tcu repair engine transmission control modules ford pcm 3000gt eclipse stealth mitsubishi honda acura lexus chrysler sidekick tracker cummins . It should be here next week. I definitely can't wait. After hearing it run right, it really sounds like crap now.

Joe
 

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Discussion Starter #12
Joe,
Catching up on the weekend posts. Glad to see that you have yours figured out. I actually read it on your other post earlier this morning.

I still don't have mine figured out yet. Just the other day I took my camper to the dealer for some repairs, and the truck actually ran smooth. It hadn't done that for a very long time. When I went back to bring it home a few days later, it was back to it's old tricks again, but this time the roughness would come and go. I could feel it at a stoplight going from rough idle to smooth and then back to rough again. Are the IDM's a known weak spot? I mean, do they go bad often?

Steve
 

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Steve,

Not sure if they go bad to often. I repair electronic equipment for a living, and do work on a lot of power amplifiers and power supplies on aircraft, and they do tend to go bad. So, yes the possibility for an IDM to go bad, since it is nothing more than a Power Amplifier, is possible. I have heard of quite a few going bad, but never knew what symptoms they could cause. A friend of mine told me that either my injectors were shot or the IDM was bad. I figured it was injectors with 220k+ miles on it, but was actually the IDM. If you can find someone with an IDM to match yours, try theirs or check with the garages and see if they have one you can try, that way you don't have to go spend any money shot gunning it. Good luck..

Joe
 

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This one is to both of you, I am having similar problems with my 97 psd, and think I have chased the running rough at idle down to that stupid dual mass flywheel, and the seems to be only running on 7 cylinders, well I haven't tracked that one down yet. I think from what I have learned about diesel engine mechanics in general it does seem like a fuel delivery issue. I am currently looking for maybe a high performance fuel pump and filter assembly that was not designed by FMC and think that maybe that will be cheaper in the long run, and fix that small balls problem. Also I am going to replace my clutch and flywheel with a solid hypo set up. I hope this helps that out. BTW, I jsut did my injector seals and saw virtually no difference in any of the problems. Also did the gp's and valve cover gaskets and wiring harnesses, cost me almost $900 for parts.
 

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those idm's usually fail becuase of condensation build up and starts to oxidize everything inside the box. also uvc wire harness and nuetral safety switchs can cause poor performance
 

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Discussion Starter #17
Based on the last couple of replies, I think my next two areas to check are going to be the UVC Harnesses and the IDM. I can rule out the flywheel as I replaced it last year when it was making a bunch of noise.

Thanks everyone for the responses.

Steve
 

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New here/Chasing same problems

Hi Guys. Im new to the fourm and just jumping in here. Hope thats ok. I have been chasing this same rough running too. Rough idle,under load,at speed runns bad everywhere, It just started a couple days ago. I have a 96 7.3 powerstroke with 75K miles. This morning I changed fuel filter,filled empty tank with fresh fuel and fuel additive, No change. I was having some of these same problem a couple years ago and it was the fuel pump,so I replaced the fuel pump today and no change. Oh I forgot to add Im NOT getting a CHECK ENGINE light or it didnt pull up any code when a buddy of mine plugged it in.??

Could some one get me up to speed on some of these abreviations and where they are located?

Blocked EBPV
FPR Shim
IPR
Unplugging the ICP

Also there was some talk about the fly wheel?? Last week I was thinking my clutch was making a bunch of noise and it seems that when i push in the clutch the roughness goes away when Im going down the road.
Thanks in advance for any and all help. Tom
 
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