1994.5 - 1997 7.3L Power Stroke Diesel  

map sensor help..

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Old 11-25-2012, 08:36 PM
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map sensor help..

with all the help of FTE i diagnosed the map sensor to be bad. unplugged she runs and pulls hard the entire time. plugged in zero power till around 2000 rpm and then she rips. takes maybe 5-6 seconds from idle to 2000 rpm. bought a brand new sensor and it performs exactly like the old one. replaced the tube from the plenium to the map also. anyway to test from the conector to the pcm? any other thoughts? maybe i got a new BAD sensor.. Thanks
 
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Old 11-25-2012, 09:09 PM
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The power in these girls kicks in around 2k, if you are talking about spooling up.
 
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Old 11-25-2012, 09:36 PM
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im talking about not even getting moving. dog big time.
 
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Old 11-25-2012, 09:40 PM
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only thing i can think of is a massive exhaust leak causing no turbo
 
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Old 11-26-2012, 06:05 AM
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Procedure to test MAP to PCM wiring harness is here ...

97-15A 7.3L DI Turbo Workshop Manual

Go to "Electronic Control System Diagnostics" -> "Manifold Absolute Pressure (MAP) Sensor". MAP is a digital device so if it was not working at all or had a bad wiring harness you would get a CEL, just like you did when you unplugged it. Make sure you purchased the correct one, what is the part number?
 
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Old 11-26-2012, 04:46 PM
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There is a exhaust leak. Not massive though. Also gets a code for low turbo pressure or something like that. I will do the map testing in the next few days. Also it seems if I don't put my foot to the floor maybe half throttle it gets to speed a little faster not even close as it should but faster. Still unplugging the map it runs perfect. So still leaning that way
 
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Old 11-26-2012, 06:02 PM
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You need to fix the exhaust leak...you will only be wasting fuel and Increasing your EGT's.....especially when you Tow.....
 
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Old 11-26-2012, 06:52 PM
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Originally Posted by blageurt
You need to fix the exhaust leak...you will only be wasting fuel and Increasing your EGT's.....especially when you Tow.....
x2 above ... fix the leaks first as I'm sure the MAP is just fine. Might want to get a boost gauge to verify. Also check the turbo inlet blades for damage as that will reduce boost. I understand you don't what to hear this but the turbo runs on a closed exhaust system. Exhaust leaks will hinder boost performance big time and unplugging the MAP just allows the PCM to make a best guess. Although you might like the performance better with the MAP unplugged, you are dumping more fuel than necessary to keep the rig moving.
 
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Old 11-26-2012, 07:35 PM
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Originally Posted by Hussler
x2 above ... fix the leaks first as I'm sure the MAP is just fine. Might want to get a boost gauge to verify. Also check the turbo inlet blades for damage as that will reduce boost. I understand you don't what to hear this but the turbo runs on a closed exhaust system. Exhaust leaks will hinder boost performance big time and unplugging the MAP just allows the PCM to make a best guess. Although you might like the performance better with the MAP unplugged, you are dumping more fuel than necessary to keep the rig moving.
x3 on this statement he put it the best way i could say it!
 
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Old 11-26-2012, 10:06 PM
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kinda thought that. because its almost like its not feeding fuel probably cause the pcm is saying theres no air. i would think with your foot through the floor and rpms takin forever to come up the egts would sky rocket but theydont go up much at all until 2000 or rpms and everything is normal
 
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