ISB intake manifold temp probe (location?)

[Johnw]

Recently had intermittent check eng light then finally light stayed on. A code check at a freightliner garage showed code 153, intake manifold temp. A couple of threads I've read suggest a dirty temp probe and cleaning or replacing to cure the problem. I've looked on the duct from the CAC to the manifold and cann't see a probe ! There is wiring at the housing where the pipe enters the manifold but doesn't appear to be a probe (large square housing). Looked all over the internet for picture or diagram of probe location with no luck. Any answers anyone. thanks.

[RustyJC]

Don't know what vintage your ISB engine is, but on my 2002 Dodge truck version (24 valve, VP44 fuel injection pump), the IAT sensor is on the driver's (fuel injection pump/intake manifold) side of the engine. If you are standing facing the intake side of the engine, the IAT sensor is located toward the rear (flywheel) end of the engine below the intake manifold.




More details HERE.


Rusty

[Johnw]

Thanks Rusty - In my haste I forgot to mention details of my ISB. We're on a 99 Freightliner chassis (Discovery Motorhome). I figured the probe would be somewhere after the charged air cooler. Your photo may help me - I'll look around more tomorrow but suspect that since our engines are on "opposite ends" the setup is different. Thanks again for the great photo. JohnW

[RustyJC]

Quote:

Originally Posted by Johnw Your photo may help me - I'll look around more tomorrow but suspect that since our engines are on "opposite ends" the setup is different.

I'll wager it's very close to where the photo shows it to be since it's a 1999 vintage 24 valve - there's no reason for Cummins to relocate it on the RV engine. The concensus of opinion is that Cummins located it there to get it downstream of the grid heater so that the temperature being sensed is as close as possible to the actual air temperature being pulled into each cylinder. Don't forget - the Cummins powered Dodge trucks of that vintage have intercoolers (charge air coolers) as well.

Let us know how you make out in your search.

Rusty

[J Walker]

On my 2000 ISB DP the sensor which Silverleaf calls the intake manifold sensor, is located where RustyJC's picture shows. So on the DP it will be on the passenger side. I removed mine two times to clean it. Paint thinner did the trick. Good as new.

[RustyJC]

Quote:

Originally Posted by J Walker Paint thinner did the trick. Good as new.

Carburetor spray cleaner also works well.

Rusty

[Johnw]

Rusty - Located just where you showed. Was looking from top of engine and its obscured under a bunch of wiring bundles from up there. Crawled underneath and there it was. Looks like a fairly straight shot to get a socket on and remove. Thanks again. Now the work begins!

JohnW