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MAP not reading above 23PSI - Bounces to "0"

2K views 13 replies 7 participants last post by  twoicebergs 
#1 · (Edited)
Fixed if you do this:

If this happens to you, go back into the PIDs and select MAP(g) psi for your boost PID. The definition says absolute pressure, but it reads relative boost correctly.

______________________________________

This is the original observation. Even the FORD dash-gauge is hooked up to the wrong PID.

The boost registered from my OBDll monitor does not read above 22.9 PSI. When it gets there, it bounces back to "0", then back and forth between the two readings. I don't have a mechanical gauge. I am 99.9% positive there are no leaks. The engine does not change operation when it does this. I still need to change tunes to see if this is part of the issue, but from as far back as 2006 there have been reports of similar occurrences with not much of an answer to the question of what is happening. I do believe the MAP does not register boost above 30 PSI (+- reading error).

Maybe the MAP is bad, but what would be the best way to test it?

If you have an OBD monitor and have the same type of issue please post:

MY: 2007
Monitor: DashBoss
OBDII PSI at cut out: 22.9
What it does next: goes to "0" then 22.9 - 0...
What does the truck do? Keeps running strong.
Mechanical Boost reading (if you have one):
Dash boost (if you gave one): 23 PSI slight bouncing
Tune name or stock: Performance Street

If it started reading better, what did you do to it?
 
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#2 ·
MY: 2006
Monitor: DashBoss
OBDII PSI at cut out: 21 or 22 to fast to really tell
What it does next: goes to "0" the. Back and forth
What does the truck do? Runs perfect no hesitation no noises
Mechanical Boost reading (if you have one):no boost gauge
Dash boost (if you have one): reads on average 25 or 30 mark hard to read.
Tune name or stock: Srl+




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#3 ·
Early 04, DashBoss hit 27psi and can go higher, analog gauge hit 30psi and can go higher. I also have a exhaust leak at exhaust manifold to block. Truck runs strong. No issue with bouncing back to 0. This was with my SRL++ tune, usually max boost on analog is 33psi. My Looney Wild and Extreme Race can peg my 35psi analog gauge.


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#4 ·
I correct myself double checked my dashboss and it just goes to zero doesn't change back and forth


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#5 ·
I tried a few different tunes and had the same result.

I kind of forgot how much power some of the race tunes have. I still have a :) on my face! I decided to leave one on for a day or 2...
 
#6 ·
Yeah I'm thinking that the map sensor is just out of range and goes to zero. There has to be a way to change map sensors to get an accurate reading from the obdII port one that reads higher then stock.


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#7 ·
I'm wondering if its the later model years (late04-07). I don't think DashBoss had this issue until the last update that gave you EBP.

My early 04 has the inferred EBP strategy and I can't get the EBP to show up on Autoenginuity, or DashBoss.

Gotta ask Bryan if he had this issue prior to the EBP update.
 
#8 ·
I put a 0-5v transducer in my intake tube. I'm still going to add another for Fuel psi and a switch but I had to order another transducer.

During warm up the intake reading is about three psi higher map, sometimes a little more, and it seems to average about three to four psi higher in most driving conditions. I did the fist wide open run from a rolling start since I got my truck back this morning. I backed out at 75 because EGT was nearly 1700! Yikes, I think that's the highest I've ever taken it. When Dashboss hit 23.2 the intake sensor keeps climbing and it maxed at 30.2.

MY: 2005
Monitor: DashBoss
OBDII PSI at cut out: 23.2
What it does next: goes to "0" then 22.9 - 0...
What does the truck do? Keeps running strong.
Mechanical Boost reading (if you have one): Dashboss presure sensor 30.2
Dash boost (if you gave one): didn't watch it, focused on egt
Tune name or stock: Spartan aggressive tow with brake
 
#9 ·
ok mine is pretty much the same, 2005 f250 pressure cuts out at 22 ish psi with dash boss. now my question is, If I out a tranducer in the intake, can I wire it inplace of the stock sensor, so I do not have to use an external dashboss port?
 
#11 ·
I'll go back and edit post 1.
 
#14 ·
Ford even used the wrong PID to show on my dash gauge! It hits 22 only and quivers in position at 22 with true higher boost.
 
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