PCM or IDM - ????
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Senior User
Joined: May 2010
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From: Rock Hill, SC
PCM or IDM - ????
I just replaced my fuel pump, bowl and fuel control manifold with Cali FPR. I have also replaced the HPOP and the IPR.
Here's my situation. Occasionally, when I need to gun her to get around some moron in the fast lane, she tends to have a "hick up" so to speak. I have the pedal floored for the most part, and experience a slight second of nothing in the middle of the acceleration. It seems like during this split second that the engine does not fire and shoots out a crap load of black smoke from the tailpipe. When the second it over, she kicks it in the butt. I do not think this is the tranny - as I have tried to see if it is on a downshift and it does not continuously occur at the same time when I have to gun her. I am leaning towards the PCM or IDM. It really feels like the PCM shuts down and there is no power and then it reboots and yehaw.
Let me know what you think... Thanks, Paul
Here's my situation. Occasionally, when I need to gun her to get around some moron in the fast lane, she tends to have a "hick up" so to speak. I have the pedal floored for the most part, and experience a slight second of nothing in the middle of the acceleration. It seems like during this split second that the engine does not fire and shoots out a crap load of black smoke from the tailpipe. When the second it over, she kicks it in the butt. I do not think this is the tranny - as I have tried to see if it is on a downshift and it does not continuously occur at the same time when I have to gun her. I am leaning towards the PCM or IDM. It really feels like the PCM shuts down and there is no power and then it reboots and yehaw.
Let me know what you think... Thanks, Paul
Postmaster
Joined: Sep 2007
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From: Medford Oregon
Sounds like a boost issue to me. To much fuel and not enough air until you spool up a bit. I would like to know if the same issue occurs when the MAP sensor electrical connector is unplugged?
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From: Rock Hill, SC
Where can I find that?
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Senior User
Joined: May 2010
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From: Rock Hill, SC
Will do that on my way home here in a few minutes. Will take me about an hour to get home. Will repost around 7.
Thanks
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From: Rock Hill, SC
Okay, so I pulled the MAP sensor. WOW. I could here my turbo spool the entire way home. have not had that much action out of my turbo it seems like. (And I have replaced my turbo and pedestal - 8 months ago - had a crack in turbo housing and pedestal).
Anyways, I gunned her and laid into her quite a bit. She did not do it at all at high speeds, but when I went from a dead stop and nailed her, she did it ever so slightly but nothing like it was. Prior to unplugging the MAP, when she did do it, it would jerk your head because of the loss of instantaneous power and then kick in and jerk your head back.
Anyways, I gunned her and laid into her quite a bit. She did not do it at all at high speeds, but when I went from a dead stop and nailed her, she did it ever so slightly but nothing like it was. Prior to unplugging the MAP, when she did do it, it would jerk your head because of the loss of instantaneous power and then kick in and jerk your head back.
Postmaster
Joined: Sep 2007
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From: Medford Oregon
So, now the question is why? Check the actual hose that goes from the MAP to the passenger intake manifold. Make sure it's in good shape and not all cracked, especially where it connects to the intake, it gets hot there. Reason I'm saying this is MAP sensors are expensive .. $150 ++ so you don't want to purchase one due to a bad hose. You can also take the hose off and ensure it's not clogged by blowing into one end.
From your comments I'm suspecting a clogged hose or a bad MAP sensor. It could be other issues causing boost leaks too.
From your comments I'm suspecting a clogged hose or a bad MAP sensor. It could be other issues causing boost leaks too.
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From: Rock Hill, SC
So, now the question is why? Check the actual hose that goes from the MAP to the passenger intake manifold. Make sure it's in good shape and not all cracked, especially where it connects to the intake, it gets hot there. Reason I'm saying this is MAP sensors are expensive .. $150 ++ so you don't want to purchase one due to a bad hose. You can also take the hose off and ensure it's not clogged by blowing into one end.
From your comments I'm suspecting a clogged hose or a bad MAP sensor. It could be other issues causing boost leaks too.
From your comments I'm suspecting a clogged hose or a bad MAP sensor. It could be other issues causing boost leaks too.
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Postmaster
Joined: Sep 2007
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From: Medford Oregon
If it was me I would suspect a bad MAP sensor then. I think we ruled out PCM and IDM due to unplugging the MAP. One option you have is to purchase a boost gauge and tee it into the MAP sensor hose. That way you can see actual boost to determine if boost is getting to the sensor.
By unplugging the MAP you enabled the PCM to make a good guess at boost using other sensors. Usually it does a good job at simulating the MAP and rule of thumb is if truck runs much better with MAP unplugged then MAP is probably bad.
There are procedures on testing the MAP sensor but requires a digital volt/ohm meter with a HZ option and a regulated air compressor to produce boost.
Edit: Here is the link for that procedure .. post #26
https://www.ford-trucks.com/forums/9...ml#post9432195
By unplugging the MAP you enabled the PCM to make a good guess at boost using other sensors. Usually it does a good job at simulating the MAP and rule of thumb is if truck runs much better with MAP unplugged then MAP is probably bad.
There are procedures on testing the MAP sensor but requires a digital volt/ohm meter with a HZ option and a regulated air compressor to produce boost.
Edit: Here is the link for that procedure .. post #26
https://www.ford-trucks.com/forums/9...ml#post9432195
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From: Rock Hill, SC
Jim -
It does appear to be the MAP sensor as you suspected. I will not be able to get one for 2 weeks till I get paid again (my monthly budget for this truck gets eaten up fast when you have to deal with fuel pump and m.c.). Anyways, unitl I am able to get the new map, should I run with the map unplugged?
It does appear to be the MAP sensor as you suspected. I will not be able to get one for 2 weeks till I get paid again (my monthly budget for this truck gets eaten up fast when you have to deal with fuel pump and m.c.). Anyways, unitl I am able to get the new map, should I run with the map unplugged?
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Laughing Gas
Joined: Apr 2009
Posts: 903
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From: melbourne beach, fl
HAd a boost concern as well and unplugged the map for results altho that didnt solve it.Found a loose bolt on the oil pan that was the fix.An oil leak is also a possibility of boost loss and a easy fix.
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