Intake Manifold Temp 220 degrees

**AK Bob** · 10-31-2023

Originally Posted by KroTacK

I am running into this same issue.

Has anyone found a solution?

I have a 2015 3500 DRW with AISIN and have tried two sensors (IAT-M), which read approximately 35 degrees higher than other temperature sensors.

I have tested this on a cold soak, and going down the road at this point, I am convinced that the reading is entirely inaccurate, as there will remain a 35-degree spread from the intake horn even as the truck warms up.

If memory serves, however, during the summer, I don't think it was 35 degrees over the intake horn reading.

It is almost as if it has to get to a specific temperature to start reading accurately.

I have e-mailed MM3 about this, and my MM3 is not reading my exhaust pressure sensor (my Edge CT3 will).

I am waiting for a response.

My main concern with this issue is I am curious if my ECM/PCM is seeing the elevated temps as well and therefore demanding my VGT to close more than it should (as the air at the manifold would be calculated as less dense than it is).

I am thinking about wiring in a completely different type of temp sensor to see if it will display accurately, but until I hear back from MM3, I will hold off.

EDIT: I forgot to mention.

My 03 5.9L does not have a temp sensor in the intake horn but has the same type of sensor (pressure/temp) that the 6.7L does in the intake manifold itself.

Even though it has a bigger intercooler, the temperatures at the manifold on my 5.9L are similar to the intake horn temps on my 6.7L.

All the more reason for me to suspect something isn't right.

I have a hard time believing that a 5.9L at the manifold and a 6.7 at the intake horn can read pretty close, but then throughout 12 or so inches, the 6.7L manifold temps increase 35 degrees on a completely flat linear curve.

If the horn says 40 degrees, the IAT-M says 75.

If the horn says 105 degrees, IAT-M says 140, and so on.

I appreciate any help you can provide.

My conclusion was a possible probe calibration issue.

The IATM sensor is an exhaust gas sensor designed to measure the EGR entering the intake manifold on a completely stock truck.

The probe isn’t accurate at lower temperatures without the exhaust gas.

I installed a new sensor, and it read the same as the original.

0 Comment(s)

**KroTacK** · 11-04-2023

Okay.. so here goes with my attempt to explain what I tried so far (and why):

To start off, I feel I have some excellent (or would be..) tuning from Codi Pitock of Pitcock AgTech (great guy to deal with, wonderful customer service so far). To each there own on tuning, but Codi and I seem to share the same thoughts on how these trucks should run. That said, we have been running into a bit of an issue with my VGT not wanting to follow his Air/Fuel tables (VGT does not want to open to 0% under light load), getting some codes after tuning that he says shouldn't be occurring, and just some Iodd gremlins generally. I have tried all of his recommendations, such as making sure the batteries are good, fully charged (I have even tuned it while jumped to one of my old truck to keep volts above 13), etc etc etc. I had it re-flashed at the dealer (both the ECM and TCM). That made a huge difference with some minor bugs I was having with the AISIN, particularly shuddering in 1st/2nd gear and a screwy shift that had been occurring between 3rd and 4th (other threads said updates would cure that and it seems to have done so for me)' trans feels wonderful now.

I re-loaded my tunes, and I am not convinced I am any better off after the updates... The "demanded" and "actual" positions are in sync, so I hesitate to think it is an actuator issue. So, I have been trying to hunt down anything that might be amiss that would cause the truck to follow a default table, or something that might skew the air/fuel tables of my tunes. In that effort, I found that my IAT-M reads almost exactly 35 degrees higher than my IAT (which I assume is the combo sensor at the intake horn) under all operating conditions (at least so far).

20231104_114507.jpg

So, that's about when I started doing some experimenting. I started by simply unplugging the IAT-M sensor. The IA-TM dropped to -5 (by the time I could make it back around from the engine bay to the driver seat) but the truck ran fine. The weird thing is, after the IAT-M reading dropped, it switch over to some other reading. Not sure if it was calculated or picking up another sensor, but it was about 10 degrees warmer than the IAT (which again, I assume is the intake horn sensor). I took the truck for a drive, and aside from a code for the sensor being unplugged it ran fine. It may have been my imagination, but it seemed like the VGT was opening a little more than it would before.

I then jumped online to see if anyone else has had this problem. The only thread I found about this particular issues is this one. I asked MM3 about it, they weren't much help, but did say that the MM3 will only display what the truck tells it to. The dealer seemed to think it was odd as well, but didn't have an answer. (Some of this may not be in order).

I then tried a sensor of an identical type. I had one left over from the EGR crossover tube (Same numbers, same exact sensor, same plug). I didn't bother pulling the old sensor, just plugged the 'new' one in and let it dangle.. Guess what, SAME READINGS ! 35+/- hotter than every other temp sensor and reading, even during cold soak.

I then decided to try a completely different style sensor, thinking maybe the sensor doesn't start giving a real value until it reaches a certain temp.. and a more sensitive sensor would do the job, after all it is just a 5volt two wire simple sensor. So.. I cut the factory plug off and wired in the old water temp sensor... That's when things got weird

20231103_163447.jpg

Not only did my IAT-M give a skew reading (engine was cold soaked in this picture), but the IAT was 419 degrees with the truck off.. It was about 55 degrees in my shop. I decided to drive it anyway....

20231103_155317.jpg

Boost was high, fuel was high, airflow was high, and VGT was more closed than it should have been for the driving conditions. Also, both IAT and IAT-M were super screwy looking.

So I took it home, and wired the old sensor back in, or so I thought. I think I may have had the wires backwards (i wasn't really paying attention to wire colors because it is a simple two wire 5 volt system, didn't think it would matter), but that is when I got this:

20231103_175301.jpg

Yep, that's the IAT reading -40 and the IAT-M which might actually be accurate as I had just drove the truck and it had sat long enough for me to wire in the old sensor. NO CODES! By this point, I had some butt-connector problems and the factory plug wires were getting shorter and short... for all I know it wasn't even making a connection and the truck just decided not to throw a code (it was pretty quick to do so when disconnected though, so I am thinking I had the wires backwards).

I drove it like this (sorry no picture) and again, unless it's my imagination, it seems like the VGT was quicker to go to 0% and was staying open more than when all the readings were "hot". Thus, supporting my theory that this wacky temp sensor may be the issue I am having with my tunes.

So.. after some cussing and fussing, and long story short.. steeling a plug from where the old EGR probe use to be (because i had accentually cut some things too short), I finally have the original probe wired back in (with corresponding wire colors) and I am back to "normal": 20231104_115200.jpg

As you can see, I am back in the same boat as before.. 35+/- hotter than IAT sensor. During all of this I did found an Intercooler outlet temperature (I have been told this is a calculated value and means nothing). I don't think anything I did helped me figure this issue out whatsoever. All I can say is this.. 35 degrees is being superficially added to the IAT-M by whatever means. It is NOT the sensor. Also, type of sensor matters as the readings were even screwier with the water temp sensor inserted.

I have though about posi-taping into my MAP/Temp sensor, but at this point I am not sure how much more butchering I want to do to my factory wiring harnesses.

All I can say I this.. if any of you go pulling that sensor and have an AISIN, good luck getting to everything without moving the oil and transmission dip-stick tubes. I did find I could run my arm under the mast cylinder area and get two hands back there, but what a major PIA to try and do anything with the wiring or the sensor because of obstructions.

I'm taping out on this one for now. Hope my write up helps someone, or motivates someone to diagnose things further than what I have done. Best wishes!

V/r,
James

0 Comment(s)

**watersupply189** · 11-04-2023

Originally Posted by KroTacK

Okay.. so here goes with my attempt to explain what I tried so far (and why):

To start off, I feel I have some excellent (or would be..) tuning from Codi Pitock of Pitcock AgTech (great guy to deal with, wonderful customer service so far). To each there own on tuning, but Codi and I seem to share the same thoughts on how these trucks should run. That said, we have been running into a bit of an issue with my VGT not wanting to follow his Air/Fuel tables (VGT does not want to open to 0% under light load), getting some codes after tuning that he says shouldn't be occurring, and just some Iodd gremlins generally. I have tried all of his recommendations, such as making sure the batteries are good, fully charged (I have even tuned it while jumped to one of my old truck to keep volts above 13), etc etc etc. I had it re-flashed at the dealer (both the ECM and TCM). That made a huge difference with some minor bugs I was having with the AISIN, particularly shuddering in 1st/2nd gear and a screwy shift that had been occurring between 3rd and 4th (other threads said updates would cure that and it seems to have done so for me)' trans feels wonderful now.

I re-loaded my tunes, and I am not convinced I am any better off after the updates... The "demanded" and "actual" positions are in sync, so I hesitate to think it is an actuator issue. So, I have been trying to hunt down anything that might be amiss that would cause the truck to follow a default table, or something that might skew the air/fuel tables of my tunes. In that effort, I found that my IAT-M reads almost exactly 35 degrees higher than my IAT (which I assume is the combo sensor at the intake horn) under all operating conditions (at least so far).

20231104_114507.jpg

So, that's about when I started doing some experimenting. I started by simply unplugging the IAT-M sensor. The IA-TM dropped to -5 (by the time I could make it back around from the engine bay to the driver seat) but the truck ran fine. The weird thing is, after the IAT-M reading dropped, it switch over to some other reading. Not sure if it was calculated or picking up another sensor, but it was about 10 degrees warmer than the IAT (which again, I assume is the intake horn sensor). I took the truck for a drive, and aside from a code for the sensor being unplugged it ran fine. It may have been my imagination, but it seemed like the VGT was opening a little more than it would before.

I then jumped online to see if anyone else has had this problem. The only thread I found about this particular issues is this one. I asked MM3 about it, they weren't much help, but did say that the MM3 will only display what the truck tells it to. The dealer seemed to think it was odd as well, but didn't have an answer. (Some of this may not be in order).

I then tried a sensor of an identical type. I had one left over from the EGR crossover tube (Same numbers, same exact sensor, same plug). I didn't bother pulling the old sensor, just plugged the 'new' one in and let it dangle.. Guess what, SAME READINGS ! 35+/- hotter than every other temp sensor and reading, even during cold soak.

I then decided to try a completely different style sensor, thinking maybe the sensor doesn't start giving a real value until it reaches a certain temp.. and a more sensitive sensor would do the job, after all it is just a 5volt two wire simple sensor. So.. I cut the factory plug off and wired in the old water temp sensor... That's when things got weird

20231103_163447.jpg

Not only did my IAT-M give a skew reading (engine was cold soaked in this picture), but the IAT was 419 degrees with the truck off.. It was about 55 degrees in my shop. I decided to drive it anyway....

20231103_155317.jpg

Boost was high, fuel was high, airflow was high, and VGT was more closed than it should have been for the driving conditions. Also, both IAT and IAT-M were super screwy looking.

So I took it home, and wired the old sensor back in, or so I thought. I think I may have had the wires backwards (i wasn't really paying attention to wire colors because it is a simple two wire 5 volt system, didn't think it would matter), but that is when I got this:

20231103_175301.jpg

Yep, that's the IAT reading -40 and the IAT-M which might actually be accurate as I had just drove the truck and it had sat long enough for me to wire in the old sensor. NO CODES! By this point, I had some butt-connector problems and the factory plug wires were getting shorter and short... for all I know it wasn't even making a connection and the truck just decided not to throw a code (it was pretty quick to do so when disconnected though, so I am thinking I had the wires backwards).

I drove it like this (sorry no picture) and again, unless it's my imagination, it seems like the VGT was quicker to go to 0% and was staying open more than when all the readings were "hot". Thus, supporting my theory that this wacky temp sensor may be the issue I am having with my tunes.

So.. after some cussing and fussing, and long story short.. steeling a plug from where the old EGR probe use to be (because i had accentually cut some things too short), I finally have the original probe wired back in (with corresponding wire colors) and I am back to "normal": 20231104_115200.jpg

As you can see, I am back in the same boat as before.. 35+/- hotter than IAT sensor. During all of this I did found an Intercooler outlet temperature (I have been told this is a calculated value and means nothing). I don't think anything I did helped me figure this issue out whatsoever. All I can say is this.. 35 degrees is being superficially added to the IAT-M by whatever means. It is NOT the sensor. Also, type of sensor matters as the readings were even screwier with the water temp sensor inserted.

I have though about posi-taping into my MAP/Temp sensor, but at this point I am not sure how much more butchering I want to do to my factory wiring harnesses.

All I can say I this.. if any of you go pulling that sensor and have an AISIN, good luck getting to everything without moving the oil and transmission dip-stick tubes. I did find I could run my arm under the mast cylinder area and get two hands back there, but what a major PIA to try and do anything with the wiring or the sensor because of obstructions.

I'm taping out on this one for now. Hope my write up helps someone, or motivates someone to diagnose things further than what I have done. Best wishes!

V/r,
James

Thank you for that excellent write-up!

I hope you can find the issue to this problem you are having.

2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

0 Comment(s)

**AK Bob** · 11-04-2023

Originally Posted by KroTacK

Okay.. so here goes with my attempt to explain what I tried so far (and why):

To start off, I feel I have some excellent (or would be..) tuning from Codi Pitock of Pitcock AgTech (great guy to deal with, wonderful customer service so far). To each there own on tuning, but Codi and I seem to share the same thoughts on how these trucks should run. That said, we have been running into a bit of an issue with my VGT not wanting to follow his Air/Fuel tables (VGT does not want to open to 0% under light load), getting some codes after tuning that he says shouldn't be occurring, and just some Iodd gremlins generally. I have tried all of his recommendations, such as making sure the batteries are good, fully charged (I have even tuned it while jumped to one of my old truck to keep volts above 13), etc etc etc. I had it re-flashed at the dealer (both the ECM and TCM). That made a huge difference with some minor bugs I was having with the AISIN, particularly shuddering in 1st/2nd gear and a screwy shift that had been occurring between 3rd and 4th (other threads said updates would cure that and it seems to have done so for me)' trans feels wonderful now.

I re-loaded my tunes, and I am not convinced I am any better off after the updates... The "demanded" and "actual" positions are in sync, so I hesitate to think it is an actuator issue. So, I have been trying to hunt down anything that might be amiss that would cause the truck to follow a default table, or something that might skew the air/fuel tables of my tunes. In that effort, I found that my IAT-M reads almost exactly 35 degrees higher than my IAT (which I assume is the combo sensor at the intake horn) under all operating conditions (at least so far).

20231104_114507.jpg

So, that's about when I started doing some experimenting. I started by simply unplugging the IAT-M sensor. The IA-TM dropped to -5 (by the time I could make it back around from the engine bay to the driver seat) but the truck ran fine. The weird thing is, after the IAT-M reading dropped, it switch over to some other reading. Not sure if it was calculated or picking up another sensor, but it was about 10 degrees warmer than the IAT (which again, I assume is the intake horn sensor). I took the truck for a drive, and aside from a code for the sensor being unplugged it ran fine. It may have been my imagination, but it seemed like the VGT was opening a little more than it would before.

I then jumped online to see if anyone else has had this problem. The only thread I found about this particular issues is this one. I asked MM3 about it, they weren't much help, but did say that the MM3 will only display what the truck tells it to. The dealer seemed to think it was odd as well, but didn't have an answer. (Some of this may not be in order).

I then tried a sensor of an identical type. I had one left over from the EGR crossover tube (Same numbers, same exact sensor, same plug). I didn't bother pulling the old sensor, just plugged the 'new' one in and let it dangle.. Guess what, SAME READINGS ! 35+/- hotter than every other temp sensor and reading, even during cold soak.

I then decided to try a completely different style sensor, thinking maybe the sensor doesn't start giving a real value until it reaches a certain temp.. and a more sensitive sensor would do the job, after all it is just a 5volt two wire simple sensor. So.. I cut the factory plug off and wired in the old water temp sensor... That's when things got weird

20231103_163447.jpg

Not only did my IAT-M give a skew reading (engine was cold soaked in this picture), but the IAT was 419 degrees with the truck off.. It was about 55 degrees in my shop. I decided to drive it anyway....

20231103_155317.jpg

Boost was high, fuel was high, airflow was high, and VGT was more closed than it should have been for the driving conditions. Also, both IAT and IAT-M were super screwy looking.

So I took it home, and wired the old sensor back in, or so I thought. I think I may have had the wires backwards (i wasn't really paying attention to wire colors because it is a simple two wire 5 volt system, didn't think it would matter), but that is when I got this:

20231103_175301.jpg

Yep, that's the IAT reading -40 and the IAT-M which might actually be accurate as I had just drove the truck and it had sat long enough for me to wire in the old sensor. NO CODES! By this point, I had some butt-connector problems and the factory plug wires were getting shorter and short... for all I know it wasn't even making a connection and the truck just decided not to throw a code (it was pretty quick to do so when disconnected though, so I am thinking I had the wires backwards).

I drove it like this (sorry no picture) and again, unless it's my imagination, it seems like the VGT was quicker to go to 0% and was staying open more than when all the readings were "hot". Thus, supporting my theory that this wacky temp sensor may be the issue I am having with my tunes.

So.. after some cussing and fussing, and long story short.. steeling a plug from where the old EGR probe use to be (because i had accentually cut some things too short), I finally have the original probe wired back in (with corresponding wire colors) and I am back to "normal": 20231104_115200.jpg

As you can see, I am back in the same boat as before.. 35+/- hotter than IAT sensor. During all of this I did found an Intercooler outlet temperature (I have been told this is a calculated value and means nothing). I don't think anything I did helped me figure this issue out whatsoever. All I can say is this.. 35 degrees is being superficially added to the IAT-M by whatever means. It is NOT the sensor. Also, type of sensor matters as the readings were even screwier with the water temp sensor inserted.

I have though about posi-taping into my MAP/Temp sensor, but at this point I am not sure how much more butchering I want to do to my factory wiring harnesses.

All I can say I this.. if any of you go pulling that sensor and have an AISIN, good luck getting to everything without moving the oil and transmission dip-stick tubes. I did find I could run my arm under the mast cylinder area and get two hands back there, but what a major PIA to try and do anything with the wiring or the sensor because of obstructions.

I'm taping out on this one for now. Hope my write up helps someone, or motivates someone to diagnose things further than what I have done. Best wishes!

V/r,
James

As you know and can confirm by reading back through this thread, I am seeing the same disparity between the IAT-M and ITA readings on my MM3. However I am not experiencing any trouble codes or tuning issues. No problems going to 0% VGT at light loads. I also have the Aisin transmission and haven’t experienced any shifting issues.

The only difference that I can tell besides your truck being a year newer is that we don’t have the same tuning. I am running the City Diesel actuator now, but didn’t experience any tuning or 0% VGT issues with the stock actuator either.

0 Comment(s)

**KroTacK** · 11-04-2023

I am curious, how light of a load does it need to be for your truck to open VGT? Maybe I am barking up the wrong tree (with the IAT-M issue), maybe I need to be looking somewhere else (and maybe it is just tuning and I am being fibbed to...). My VGT will open to 0% under the perfect conditions but it isn't consistent.. Then sometimes when I think it ought to be for sure at 0% it won't be (such as un-laden, down hill, with a tail wind...). I can also get it to go to 0% at idle, so long as the truck has been brought to full operating temperature. Sometimes, I have to give the throttle a little romp, and it will go to 0%. I'd replace the actuator if I thought it was the issue, but I am just not convinced; mainly because the VGT position is always within about a hundredth of what it is being demanded to do. It certainly seems to have it's full range of motion. The odd thing, it almost seems to be in conflict with something. As if one parameter is telling it to open, while another is telling it to close. When it does open to 0%, all I have to do is think "oh, there it goes..." and that's enough for it to snap back to about 50% closed. It's really really really (did I mention really?) driving me up the wall!

Thanks for your input!

V/r,
James

0 Comment(s)

**AK Bob** · 11-06-2023

Originally Posted by KroTacK

I am curious, how light of a load does it need to be for your truck to open VGT? Maybe I am barking up the wrong tree (with the IAT-M issue), maybe I need to be looking somewhere else (and maybe it is just tuning and I am being fibbed to...). My VGT will open to 0% under the perfect conditions but it isn't consistent.. Then sometimes when I think it ought to be for sure at 0% it won't be (such as un-laden, down hill, with a tail wind...). I can also get it to go to 0% at idle, so long as the truck has been brought to full operating temperature. Sometimes, I have to give the throttle a little romp, and it will go to 0%. I'd replace the actuator if I thought it was the issue, but I am just not convinced; mainly because the VGT position is always within about a hundredth of what it is being demanded to do. It certainly seems to have it's full range of motion. The odd thing, it almost seems to be in conflict with something. As if one parameter is telling it to open, while another is telling it to close. When it does open to 0%, all I have to do is think "oh, there it goes..." and that's enough for it to snap back to about 50% closed. It's really really really (did I mention really?) driving me up the wall!

Thanks for your input!

V/r,
James

Observed my VGT % today just driving around town. The conditions were as follows; Outside temperature 30*F from cold start to normal opening temperature with exhaust brake off. Light acceleration and maintaining speed VGT 33%. At 40 mph release the accelerator and coast VGT drops below 10%
immediately until 15 mph where it drops to 0%. These results were consistent throughout the 15 mile test, actual and desired were tracking spot on. Keep in mind I do have the City Diesel actuator installed.

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