400 ISL - Faulty Intake Manifold Temperature Sensor?

[Bill R]

The other day while doing some PM on the engine, I noticed the Intake Temperature was around 167F on the Aladdin Jr.  Looking at troubleshooting guides in Quickserve, it states that the intake temp should not get higher than 38F above the ambient temperature.  It was only 85F outside at the time.

Came back today to do more troubleshooting.  Before even starting the engine, the intake temp was still reading 167F.  Started the engine and no change.   See the pic #1 below.   Strange thing is that the Outside Temp on the Aladdin Jr was reading 5.9F.

I took the coach for a spin to see if the temps changed.  Boost was good, no black smoke, all gauges normal, except the Intake temp went up to around 197F and I got the "stop engine" light.  Pulled over, shut engine off.   See pic #2.  I took a thermal temp reading of the Intake Pipe and it only showed 106F.  See pic #3.  So I am confident the Intake Manifold Temp Sensor is not reading correctly.  The Outside Temp went up to around 76F, it was 90F outside.  Started coach back up, "stop engine" light went off, this time the intake temp stayed below 180F, and I drove back to my storage unit.  The "stop engine" light did not come back on.

I did some searching on this site and found some posts that helped me locate the sensor.  Cummins gave me the part number 4088832.  Seems to be a simple job and not an expensive part.  But I do have a few questions below.

1)  Would a high intake manifold temp cause the "stop engine" light to come on?

2) Where is the Outside Temp indication on the Aladdin Jr reading?  On the Quickserve site ECM drawing it shows a "turbocharger compressor intake temperature sensor".  Would this be it?  Where would that be located?

3) Any other tips, tricks, or other things I should be considering.  

 

 

[Frank McElroy]

Not sure about the Aladdin outside air temp sensor location on a Windsor but on my dynasty it's in the bay with the propane tank on the driver's side.

The best way to find out why a stop engine light came on is to read the stored inactive codes.  The best I can tell, faults related to the Intake manifold air temp will turn on a yellow check engine light.  But if the engine derates it might be approaching the engine protection limits and turn on a stop engine light to prevent engine damage.

[Bill R]

Thank you @Frank McElroy.  The check engine light never came on, only the stop engine.  It never started to derate either.  Is that normal?

And I'll be looking for that air temp sensor in the propane tank area.  May have two bad temp sensors going on at the same time.

[Bill R]

Found the temp sensor for the Aladdin Jr Outside Temp.   Have part number and will be replacing that.

Has anyone had to replace the Intake Manifold Temp Sensor on their coach?  Seems like a strange part to just go bad.  I pulled it today, cleaned the terminals with DeOxit and cleaned the probe.  But no change to a temp of 177F before even starting the engine.  Plan to go to the local Cummins Parts on Monday.

When I disconnected the sensor I would get a check engine light.  So that is a confirmation that the ECM is reading something.

 

[96 EVO]

2 hours ago, Bill R said:

Found the temp sensor for the Aladdin Jr Outside Temp.   Have part number and will be replacing that.

 

 

Where?

[Bill R]

Good question Ben, @96 EVO, I should have mentioned it.  It was on the passenger side front storage bay, mounted on ceiling of bay.  I disconnected the input to confirm this was it.  The Aladdin Jr display went to -33F when I did.  Here is a pic.  

 

[Frank McElroy]

27 minutes ago, Bill R said:

Good question Ben, @96 EVO, I should have mentioned it.  It was on the passenger side front storage bay, mounted on ceiling of bay.  I disconnected the input to confirm this was it.  The Aladdin Jr display went to -33F when I did.  Here is a pic.  

 

From your picture, it looks like the actual sensor is still inside the storage bay.  On my Dynasty the outside sensor is located outside.  In my photo, the DS bay door is to the left, the propane tank is to the top and the fuel tank is on the right.  The end of the sensor is just below the frame tubing.

[96 EVO]

That's what I was thinking.

Outside temp sensor shouldn't be in a bay!

[Frank McElroy]

16 minutes ago, 96 EVO said:

That's what I was thinking.

Outside temp sensor shouldn't be in a bay!

Are you sure you don't have a bay AND an outside sensor?

[96 EVO]

My Aladdin Jr displays 'Outside Temp'.

Seems to be accurate, so I've never needed to go hunting for it.

[Bill R]

The sensor you can see in the pic is for the Bay Temp.  There is another temp sensor coming out of the Aladdin Module which is for the Outside Temp and goes into the chase and I will have to trace that to see where it ends up.   I have looked all over the propane bay for the end of the Outside Temp sensor with no avail.  But I now have a starting point.

[96 EVO]

Ha, maybe I have bay temp in my Aladdin as well.

I'm sure it has pages in the menu I haven't even seen 😁!

[bgfleck]

Not sure but is it possible the Aladdin JR only has outside temp, and that sensor was never routed to the outside. On our Aladdin system there is and outside temp and a basement temp.

[Frank McElroy]

16 minutes ago, Bill R said:

The sensor you can see in the pic is for the Bay Temp.  There is another temp sensor coming out of the Aladdin Module which is for the Outside Temp and goes into the chase and I will have to trace that to see where it ends up.   I have looked all over the propane bay for the end of the Outside Temp sensor with no avail.  But I now have a starting point.

Look at the other side on that Aladdin module and see if the outside sensor is plugged in.  Then just follow the wires to the sensor.  You could also reset the outside sensor plug on the module - it could have corrosion on the connector.

[Bill R]

2 minutes ago, Frank McElroy said:

Look at the other side on that Aladdin module and see if the outside sensor is plugged in. 

Yes sir, I did, and there are two sensors coming out of the Aladdin module.  I cleaned both the terminals and reinstalled.  No change.  I even swapped the inputs and saw the temps change on the Aladdin display respective to the sensor.  So pretty sure it is a bad sensor or connector at the sensor end that may need to be cleaned and/or secured.  Just need to trace it now.  Project for Monday.  Along with getting a new intake manifold temperature sensor.

@96 EVO If you page down on the Aladdin Jr page from the Outside Temp, you should see the Bay Temp display.  That's how it is on mine.

[96 EVO]

Thanks Bill. I'll have a look.

Generally just use the Aladdin for fuel use, and trip meters. I have a Scangauge for watching engine functions.

I also prefer to use the monitor while moving for watching what's going on behind me.

[Frank McElroy]

6 minutes ago, Bill R said:

Yes sir, I did, and there are two sensors coming out of the Aladdin module.  I cleaned both the terminals and reinstalled.  No change.  I even swapped the inputs and saw the temps change on the Aladdin display respective to the sensor.  So pretty sure it is a bad sensor or connector at the sensor end that may need to be cleaned and/or secured.  Just need to trace it now.  Project for Monday.  Along with getting a new intake manifold temperature sensor.

@96 EVO If you page down on the Aladdin Jr page from the Outside Temp, you should see the Bay Temp display.  That's how it is on mine.

The temp sensors are basically a thermal couple of two discimilar metals and they rarely fail.  But on mine the sensor plugs into another connection just out of the picture.  Once you trace the wires, you might find another connector that might be corroded.

[96 EVO]

Found the basement air temp on the Aladdin monitor!

Now I'm curious and may have to find the sensors as well!

[TommyL]

Thanks to 96 evo we been able to toggle between rear camera and engine monitor while moving, and yes we have bay temperature. Thanks Ben .

Tommy and Cheri 08 Camelot isl400 tag

[DennisZ]

I had to replace my outside air temp sensor several years ago, mine is located in the fuel bay on the passenger side, the whole bay is open to the outside world, so an outside temp. On mine, it is not a thermocouple (2 dissimilar wires twisted), but a special diode, I had to buy like a hundred od them, but they were cheap.

[Frank McElroy]

45 minutes ago, DennisZ said:

I had to replace my outside air temp sensor several years ago, mine is located in the fuel bay on the passenger side, the whole bay is open to the outside world, so an outside temp. On mine, it is not a thermocouple (2 dissimilar wires twisted), but a special diode, I had to buy like a hundred od them, but they were cheap.

Good point - I forgot about the diode option for temperature sending.  Do you have info on a part number and where you bought them?

[DennisZ]

Unfortunately that was long ago, my memory and purchase history are long gone.

[Bootlegger 659]

Bill, I just replaced my intake temp sensor.  It did throw a stop engine code and put it in D-rate mode. An insight software expert from another site said he had never seen that before In his entire career.  Go figure, it happened to me. After replacement all things are normal. So you are not the only one! This was on a 8.8L ISL 400.

[Bill R]

Thank you @TommyL @96 EVO @DennisZ and @Frank McElroy for all your input.  Before I open up the chase and start tracing the wire, I am going to do another good look in the diesel/propane tank bay for the temp sensor.  Now I know better what I am looking for.  It does make sense that it should be there since it is open to the outside.  Will follow-up.

@Bootlegger 659 Thank you for sharing your experience.  EXACTLY what happened to me.  So I have more confidence now that this is the issue.  Will report back.

[96 EVO]

When I checked my Aladdin last night, the entire coach was in the shade, ambient temp about 72F.

The outside temp sensor was reading 85F, so, I'm thinking they may have mounted it somewhere that retains heat.

I was thinking behind the black paint of the front cap, but that doesn't make sense as it would be exposed to the rising heat from the generator.