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Discussion Starter · #1 ·
Hey guys I have a 7.3 Ford F-350 super duty I have spent a lot of money trying to fix my problem. It lose power wen going up hill wen I try to give it sum gas it does nothing the speed hand just drops n drops all the way down to 30 miles per hour until I get up the hill n on flat ground it’s back driving smooth there is no check engine light on took it to 2 shops n only thing they did is put a bunch of new parts on it that didn’t fix the problem I had tank clean 1 injectors is new because it did have 1 code n it was injector #3 so I replaced it n now there is no code on checking engine I put icp,cam sensor, new fuel pump new gas line had transmission check it’s good they said turbo is getting right boost one guy from the diesel shop I went to even came to my house n we went uphill n he had his laptop hook up reading the fuel pressure n all of that n we still couldn’t tell me wat it was that was making my truck do that going uphill he say everything was reading right I mean I did a lot now the last shop I took it to they put a tune on it but the truck does the same thing going uphill wit the tune on it so iam just lost n need help


Anyone have any ideas I was thinking bout changing the idm n the little box that’s above the accelerator pedal
 

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That's the ECM, the IDM is in the drivers side wheel well housing. However, that is likely not it. A common solution to this problem is in the fuel tank. The pick up foot rots and when the tank is low enough and you tilt uphill it will suck air. When the tank was cleaned did they replace the pickup foot? Another possible cause is low oil or a cracked low pressure oil pickup tube. I'm sure someone else will chime in with some other solutions.
 

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Discussion Starter · #3 ·
That's the ECM, the IDM is in the drivers side wheel well housing. However, that is likely not it. A common solution to this problem is in the fuel tank. The pick up foot rots and when the tank is low enough and you tilt uphill it will suck air. When the tank was cleaned did they replace the pickup foot? Another possible cause is low oil or a cracked low pressure oil pickup tube. I'm sure someone else will chime in with some other solutions.
Yes everything in the tank is new n I even filled it up wit gas n went uphill it did the same thing
 

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You are to the point that you are going to need a scan tool that can read live data, and then go for a ride while someone is watching the data for high pressure oil, and a few of the sensors.
 

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Discussion Starter · #7 ·
You are to the point that you are going to need a scan tool that can read live data, and then go for a ride while someone is watching the data for high pressure oil, and a few of the sensors.
I did have that done the first shop I took it do did that we went uphill in the truck n he had his laptop hook up reading all that stuff n he told me everything was reading right good fuel pressure good boost he told me that he recommended that I put a tune on it to give it more hp did that n still having the same problem
 

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Discussion Starter · #8 ·
I know you said he checked the boost levels, but it definitely sounds like you aren't making enough boost... I would personally return the tune to stock while diagnosing in case certain faults are disabled or something.
Yep they check my back pipes for leaks n they check around the turbo for leaks n said it had no leaks I ask do he think I need a new turbo he said no because it doing wat it’s supposed to do
 

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If they suggested to put a tune on it to cure a problem I would find another shop.

These trucks have plenty of power to pull themselves up a hill. I can drive mine up a hill to over 10,000 starting at 8,000' in just a few miles at well over the speed limit with a pretty much stock truck.

Has the map sensor been replace?
 
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Discussion Starter · #10 ·
If they suggested to put a tune on it to cure a problem I would find another shop.

These trucks have plenty of power to pull themselves up a hill. I can drive mine up a hill to over 10,000 starting at 8,000' in just a few miles at well over the speed limit with a pretty much stock truck.

Has the map sensor been replace?
No I dnt think the map sensor has been replaced I mean the truck drive fine pulls off great no lights on the only problem is wen iam going uphill I can have my feet on the accelerator going 70 miles a hour then once I start going uphill my speed just drops fast I try to give it gas n it does nothing I can floor it n it still does nothing it dnt even rev up or nothing but once iam on flat ground it rev up n do wat it supposed to do now it does all this wen my trailer is hook up now if I take the truck it’s self up a hill aww she does fine it only do it wen I hook my trailer up
 

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The map sensor won't allow boost to build until fuel is being dumped into the cylinders building more exhaust to spin the turbo faster.

On flat ground you will use very little boost until you put a load on the engine such as flooring the throttle pedal to pick up speed and even then on flat ground the boost will be very little. On my truck I'll run around 1-2 lbs of boost on flat ground at 75mph, if I floor it the boost will go up to around 10 lbs, going up a good hill when I get the tubo spooling up good I'll hit 15 lbs+ and have to back out of it due to being way over the speed limit.

If the sensor isn't working right it will just sit there at a default position I believe.
 

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Discussion Starter · #12 ·
No I dnt think the map sensor has been replaced I mean the truck drive fine pulls off great no lights on the only problem is wen iam going uphill I can have my feet on the accelerator going 70 miles a hour then once I start going uphill my speed just drops fast I try to give it gas n it does nothing I can floor it n it still does nothing it dnt even rev up or nothing but once iam on flat ground it rev up n do wat it supposed to do now it does all this wen my trailer is hook up now if I take the truck it’s self up a hill aww she does fine it only do it wen I hook my trailer up
The map sensor won't allow boost to build until fuel is being dumped into the cylinders building more exhaust to spin the turbo faster.

On flat ground you will use very little boost until you put a load on the engine such as flooring the throttle pedal to pick up speed and even then on flat ground the boost will be very little. On my truck I'll run around 1-2 lbs of boost on flat ground at 75mph, if I floor it the boost will go up to around 10 lbs, going up a good hill when I get the tubo spooling up good I'll hit 15 lbs+ and have to back out of it due to being way over the speed limit.

If the sensor isn't working right it will just sit there at a default position I believe.
ok iam going to try that… but he did say it had 15 pounds of boost when he had his laptop hook up I will most definitely try a new map sensor on it b4 I put any more money in it
 

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It doesn't make any sense if you had 15 lbs of boost and the engine was loosing power.

Post up where you are located, there might be a shop that a member here knows about that could help you. It doesn't sound like the ones that you went to did.

A map sensor runs around $100 so I wouldn't just change it out until you know for sure.
 

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Discussion Starter · #14 ·
It doesn't make any sense if you had 15 lbs of boost and the engine was loosing power.

Post up where you are located, there might be a shop that a member here knows about that could help you. It doesn't sound like the ones that you went to did.

A map sensor runs around $100 so I wouldn't just change it out until you know for sure.
Yep that’s wat he said that’s why he was puzzle on wat it could be that’s making the truck do that it was not doing that at first it just started doing that out of no were I do hotshot n I had 10,000 pounds on the trailer b4 n It want doing that I was telling the guy that wen he said that it needed more hp that tune


I am from Greenwood Mississippi
 

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How does it run with no trailer?

But what has me stumped is when you say that it looses all power going up hill but when the tech checked it he said that you were running 15 lbs of boost. That just doesn't make any sense.

When they did their test was it still loosing power when it had the 15 lbs of boost?
 

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Discussion Starter · #16 ·
How does it run with no trailer?

But what has me stumped is when you say that it looses all power going up hill but when the tech checked it he said that you were running 15 lbs of boost. That just doesn't make any sense.

When they did their test was it still loosing power when it had the 15 lbs of boost?
Wen it’s no trailer on the truck it pulls up a hill fine it only lose power wen I have the trailer hook up…. N yep he said the boost was fine even wen we was going up the hill n it was losing power he said he was getting 15 pounds of boost both shops said the same thing
 

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Have you tried downshifting to keep in the power band of close to 2000 RPM's. If you get below that you are going to be dead in the water.

Also if you are hotshotting and towing weight I would suggest that you get some gauges to monitor what is going on in the engine and transmission. I am almost certain that you have ran your exhaust temperatures way above what is safe and I am betting that you have a automatic transmission that has see higher temperatures that it should.

At the very least I would have a EGT (exhaust gas temperature), transmission temperature, and possible a boost gauge to watch what is going on while towing. At the very least the EGT, and transmission temperature gauge.
 

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Discussion Starter · #18 ·
Have you tried downshifting to keep in the power band of close to 2000 RPM's. If you get below that you are going to be dead in the water.

Also if you are hotshotting and towing weight I would suggest that you get some gauges to monitor what is going on in the engine and transmission. I am almost certain that you have ran your exhaust temperatures way above what is safe and I am betting that you have a automatic transmission that has see higher temperatures that it should.

At the very least I would have a EGT (exhaust gas temperature), transmission temperature, and possible a boost gauge to watch what is going on while towing. At the very least the EGT, and transmission temperature gauge.
Yep he tried the down shift we even put it in overdrive to see will it pull up a hill it didn’t work….. it gotta be sun simple that making it do that
 

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The last time I was loosing power pulling a hill with a 32' 5th wheel trailer behind me it was my exhaust backpressure sensor was plugged my truck is a 95 not sure on the 99 and ups. If you have one it is located on top of the front of the engine close to the alternator you will see a stainless or copper tube coming from the sensor going to the front of your passenger side exhaust manifold. When mine was loosing power I had no check engine light and no codes were stored I just noticed the truck was struggling to pull when I hit the hill. I was showing boost but, it wasn't what it should have been. It won't cost you any money to pull the sensor off and clean it no, need to replace as they rarely ever go bad. I had almost 1 million miles on the original sensor I would just pull it off every couple years and clean it. To clean it pull it off turn it upside down use a small eyeglass screwdriver stick it in there and gently scrape it around turn it over a tap it on a hard surface into a paper towel you will see the black carbon crud that builds up. Then take some brake kleen or starting fluid and spray it in there tap it out spray some more in there scrape around with the screwdriver tap it out. Do it a few more times and before you put it back in look down into the tube and see if it has build up inside the opening if it does scrape it with the screwdriver and start up the truck with the sensor off and it will blow out the crud and yes, it will turn on the check engine light. Put the sensor back in and try to pull your trailer again hopefully, it will. Unless, you have a scanner you will need to disconnect the batteries for about 10min to turn off the check engine light. Not sure if it is your problem but, like I said it is free to try. Good Luck! and keep us posted.
 

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Discussion Starter · #20 ·
The last time I was loosing power pulling a hill with a 32' 5th wheel trailer behind me it was my exhaust backpressure sensor was plugged my truck is a 95 not sure on the 99 and ups. If you have one it is located on top of the front of the engine close to the alternator you will see a stainless or copper tube coming from the sensor going to the front of your passenger side exhaust manifold. When mine was loosing power I had no check engine light and no codes were stored I just noticed the truck was struggling to pull when I hit the hill. I was showing boost but, it wasn't what it should have been. It won't cost you any money to pull the sensor off and clean it no, need to replace as they rarely ever go bad. I had almost 1 million miles on the original sensor I would just pull it off every couple years and clean it. To clean it pull it off turn it upside down use a small eyeglass screwdriver stick it in there and gently scrape it around turn it over a tap it on a hard surface into a paper towel you will see the black carbon crud that builds up. Then take some brake kleen or starting fluid and spray it in there tap it out spray some more in there scrape around with the screwdriver tap it out. Do it a few more times and before you put it back in look down into the tube and see if it has build up inside the opening if it does scrape it with the screwdriver and start up the truck with the sensor off and it will blow out the crud and yes, it will turn on the check engine light. Put the sensor back in and try to pull your trailer again hopefully, it will. Unless, you have a scanner you will need to disconnect the batteries for about 10min to turn off the check engine light. Not sure if it is your problem but, like I said it is free to try. Good Luck! and keep us posted.
Thank you I will surely try this tomorrow thanks
 
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