Boost 0.0 cold engine - 21.3 warm engine

[bry1216]

Anybody see a boost reading on a Scangauge II showing Boost 0.1 cold engine and 21.3 after it warms up?
While cold it drives like a slug, but when warm drives like a dragster.
Thanks for any comments.

Edited October 10, 2014 by bry1216

[CUMMINSDIESELPWR]

possible map sensor going out? when cold it isnt reading properly perhaps?

[bry1216]

There is no variable in these 2 values it is 0.1 (runs poorly) or jumps 21.3 (runs great).

Edited October 10, 2014 by bry1216

[Mopar1973Man]

Any error codes?

[bry1216]

No codes yet.

[bry1216]

Codes do work.  I pulled MAP connector and got a P0237.

I pulled both MAP sensor and IAC.  Both look really clean.  Reinstalled and same problem.

I did notice the BST at 0.0 until water temperature was 170'f, then BST jumped to 22.1.  Temp rose to 202'f and then cooled to 190'f and stabilized at 195'f.

 

Do anybody have a ScanGauge 2 that could describe the BST values they are getting?

 

Thank you.

Edited October 12, 2014 by bry1216

[Mopar1973Man]

Here is your P0237 code...

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/167-p0237-map-sensor-voltage-too-low

 

This will give you all the diagnostics to test out everything...

[bry1216]

Replaced the original sensor with new Cummins 492147 (Geno's Garage) and problem fixed.   Look at the ohm readings of new and old and the opening size.

 

Socket size:
Old sensor 1 1/4
New sensor 1 1/16

[Mopar1973Man]

What's weird is this should of thrown a code on the truck might not of set the MIL light but still should of set a code. If not then this is a classic case of a sensor failing within specs and not tripping a code but feeding the ECM poor data.

[bry1216]

Small correction Michael - There were some codes in the beginning, but it was P0236 and P0382 codes and I found the plug in control wire off.  From the time I cleared it to pulling the MAP connector P0237 - cleared it - and after no codes.

 

I check all the grounds to the body in the engine area.

 

If anyone get time I would like to know your ohm measurements and socket size (determine if it is original or later Cummins part).

Edited October 18, 2014 by bry1216

[Mopar1973Man]

Ohm measurement will be skewed from person to person. Why? Because it measuring PSIa (atmosphere) not PSIG (pressure). So just two people from two different elevations could possibly have two different numbers. Like sea level should be 14.3 PSIa but here at my place be roughly 13.0 PSIa.

 

So its best to read it with a live data tool and compare it to a mechanical boost gauge.

 

Closer you get to 0 PSIa is a vacuum.