Engine/Transmission (1998.5 - 2002) IAT sensor (cleaned )

[bow hunter]

I cleaned the Intake Air Sensor with some intake air cleaner blew off all the grime and it lowered egts, Must be reading more accurate truck runs alot stronger.

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98. 5 SLT Q/C L/B intense blue loaded 3. 54 5 speed straight exhaust,isspro boost egt dual pillar, bullydog stage II injectors NRA MEMBER,8000k Ramsey winch mount front or rear,20ft GN stock trailer

 

[PAYCHECK]

bow hunter, could you give more details on how you did this? will what you did bother anything else in the engine compartment? please! more details. thanx, from the high mountains of wy.

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01 2500HD QC,SB,3. 54,5 spd,4X4,241HD,SLT+,Sport all black,fully loaded,all leather htd,jacobs e-brake,tow pack,camper pack,,full rhino lining bed and rocker panels,265/75r16 BFG ATs ko,nerf bars,everthing black,4'' Jardine,A. M. Pro Comp pyro & boost on a-pillar,EZ,NO stickers except cummins on door,License plate-1 CUMN, NRA endowment life member

 

[bow hunter]

PAYCHECK,
I have 56,000 with the K&N in no dirt any where but I had a little grim probably from the K&N oil plus all those miles. I took a 22mm socket the IAT is to the right of the MAP sensor which is just above the fuel filter take it out and spray it off with air intake cleaner for carbs or fuel inj. The cleaner makes the sensor look like new.

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98. 5 SLT Q/C L/B intense blue loaded 3. 54 5 speed straight exhaust,isspro boost egt dual pillar, bullydog stage II injectors NRA MEMBER,8000k Ramsey winch mount front or rear,20ft GN stock trailer

 

[Alan Reagan]

You know, I would have thought this would have been about the most unnecessary thing I could ever do, but my curiosity was up so I pulled the IAT last night to take a look. The first thing that I noticed was how loose (not good and snug) the IAT sensor was. I spent all that time getting the ratchet on it and I think I could have turned it with my fingers. Anyway, I pulled it and cleaned it. Now I don't know if the cleaning did anything or putting it back in tight made a difference but there is a difference. I attibute my 1 lb gain in boost and faster spool up to tightening the sensor and probably stopping a pressure leak. A few more days driving will tell, but the truck definitely feels different (better) after performing that little operation. While I had it out I used Marco's post on the typical resistance readings. I stuck it in the freezer to cool it and sat it on the radiator to heat it. My readings seemed to be a little off (about 2000 ohms) from Marco's on a new one so I may change it soon.

Bow Hunter, thanks for the tip. I would have never believed that doing anything like that would make such an apparent difference.

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2001 HO 6 spd 2500, 4. 10 LSD, Towing Package, Electric Brakes, SPA EGT/Boost Gauges, Fog Lights, Real Backup Lights, Molded Running Boards, Lucerix X Mount Heated/Power Mirrors

 

[Max Wedge]

I have 13,400 miles on truck and took it to the dealer today to have IAT sensor checked and the tech told me that the voltage was a little high coming out--I think he said 2. 9v and so he replaced it and it read around 1. 7v so I will see if there is any difference in mpg.

Thanks Marco for the heads up, if I wouldn't have had the dealer check it they never would have. Tech ask me how I knew to have him check it, and well I..... forgot and changed subject.

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Y2K Black 3500 4x4 SLT+ Leather ETC/DGA DMF/DSA Luverne SST Bars
'64 Plymouth 426 III (Max Wedge)
'79 Chrysler 300 T-Tops NRA Member

 

[Diesel Freak]

where is it located?

 

[PAYCHECK]

BOW HUNTER, thanx for the very good info!!! i am going to clean mine,pronto. i think i will just buy one for the tool box as they are only 20 bucks. thanx again.

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01 2500HD QC,SB,3. 54,5 spd,4X4,241HD,SLT+,Sport all black,fully loaded,all leather htd,jacobs e-brake,tow pack,camper pack,,full rhino lining bed and rocker panels,265/75r16 BFG ATs ko,nerf bars,everthing black,4'' Jardine,A. M. Pro Comp pyro & boost on a-pillar,EZ,NO stickers except cummins on door,License plate-1 CUMN, NRA endowment life member

 

[Alan Reagan]

Cdaledh, Looking from the drivers side, it's to the right of the fuel filter, then MAP sensor, almost on the rear of the engine but a little lower than the MAP. You'll see the connector easier than you'll see the sensor. I had to feel for the sensor. I've ordered one because the 2000 ohm difference. That much difference would cause a higher voltage drop and thus throw the reading off.


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2001 HO 6 spd 2500, 4. 10 LSD, Towing Package, Electric Brakes, SPA EGT/Boost Gauges, Fog Lights, Real Backup Lights, Molded Running Boards, Lucerix X Mount Heated/Power Mirrors

 

[Marco]

Glad to hear that someone can take advantage from the findings of another guy!
TDR IS a great place, isn't it?

Alan 2k Ohm lower will make the ECM think that the air temp is lower than it actually is. Thus it will inject more fuel than what can be burned. I guess, you will get an MPG increase like me, when I changed the IAT sensor out.

The sensor was loose??? Hmmmmmmm, maybe it's better I'll check the MAP sensor also for tightness... .
Marco

 

[Alan Reagan]

Marco, If that's the case, that probably explains the increase in black smoke I've had since the weather warmed up. Although it looks nice it's not normal for my truck. All of this is beginning to make a little more since. Thanks for your post about the IAT. My mileage is great now, so I don't look for much increase there. Yeah, the sensor was loose and I was probably loosing boost. Not now.

 

[Marco]

Alan,
When you get the new IAT sensor in, please let us know your findings!
Thanks,
Marco

 

[Alan Reagan]

Will do. The dealer ordered it for me last week. I went through a pretty comprehensive measurement process with the one that's in there now. I cooled it, warmed it on the radiator, did the ambient, etc. It will be interesting to see the difference. Thanks to you and Bow Hunter.

 

[B. Gill]

Marco,i am sorry tried to find the thread but could not,can you please post once again what the readings should be ?
one more question, how do people in little cars treat you in Italy #ad

thanks
bob

 

[bow hunter]

Marcos readings are 32 it should read 30k to 36k omh
77 9k to 11k
122 3k to 4k
167 1350 to 1500 omh
212 600 to 675 omh
thanks marco for getting us thinking

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98. 5 SLT Q/C L/B intense blue loaded 3. 54 5 speed straight exhaust,isspro boost egt dual pillar, bullydog stage II injectors NRA MEMBER,8000k Ramsey winch mount front or rear,20ft GN stock trailer

 

[JR2]

I took the IAT out of two different trucks today. My Dad's 1998. 5 with 60K+ miles on it was absolutly filthy. Covered in black soot and gunk. I cleaned it with starting fluid and put it back in. Mine (a 2001) with 11K miles was slightly oily, but clean. I don't know if it will make a difference but I will report back as soon as Dad runs a tank of fuel through the truck. I am going to replace mine just to see if it makes a difference.



By the way, the sensor does not use a 22mm socket, that is too big. I used a 13/16th spark plug socket and it fit perfect.



Assuming this attachment thing works, there will be a pic of my dad's dirty sensor attached.

 

[JR2]

Dad just drove his truck for a few hours and says the EGT is lower by 120 degrees at idle in neutral.



My truck in drive while not moving is just shy of 500 degrees... and around 350 in park. I am replacing mine as soon as I can get to the dealer.

 

[Marco]

WOW!

John, where did all that soot come from?

Interesting!!! Something more to investigate about!



When I took my sensor out it didn't have all that soot. It's also true that my truck has only 25K miles on it.



My truck showed 450°F at idle in D, 350 in N.

With the new sensor, it's at 350/375 in D and arround 200 in N.

I've noticed that the EGT's cool down much faster with the new sensor too.



Just another thought. If the IAT sensor was so dirty, what looks the MAP sensor like? If the MAP sensor has soot on it, what happens??? Hmmmmmmmm... ... ... ...

Marco.

 

[JR2]

Marco,

I was wondering where all that stuff came from also. Dad had some stuff to do yesterday so I did not get a chance to pull the MAP sensor to check it but I bet it is filthy also.

Do you have any idea what would cause that sort of build up.



Your numbers seal the deal, I will be replacing my IAT as soon as I go to town.

 

[Steve Campbell]

I have a thought about where all of that "stuff" comes from. There is a certain amount of valve overlap on most engines. If the Cummins is not an exception to that "rule", then exhaust could maybe make its way into the intake under down hill coasting conditions, idiling(Both of these would relate to exhaust system back-pressure being marginally higher than intake pressures) or the use of an exhaust brake (back pressure being substantially higher than intake pressure). Ok gurus, have a shot at my theory and let everyone know where I failed Logic or just a case of my cranium being too small

 

[Jack in Alaska]

IAT looseness

As an additional comment about the IAT looseness... . as it is an internal o-ring seal it only needs to be snugged up or "handy" in oilfield jargon. When the pressure hits it from the inside the o-ring swells up making it impossible to loosen up. Tightening it real tight does nothing but make it harder to get off.