Engine/Transmission (1998.5 - 2002) IAT sensor - check it occasionally

[Gary - K7GLD]

HMmmmm - still doesn't quite answer my question - *I* don't have either an exhaust brake, OR any EGR stuff - so WHAT is it that gets the IAT dirty? The part of my intake I can easily inspect, at the inlet to the turbo and that portion of the intake tract, stays entirely pristine and clean - so WHY would the intake air somehow get DIRTY enough further on down toward the manifold, to foul the IAT?



I mean, IF the IAT in MY setup was getting so dirty as to need that much attention without an exhaust brake or EGR, *I* would be getting pretty concerned about my air cleaner efficiency!



Gotta be some OTHER complicating factor involved!

 

[Big White Beast]

Gary.......

Haven't checked mine lately but... ... . The air filter I sold you is what got mine dirty. Oily any way. That was why I opted out of the oiled filters. After going to the BHAF I no longer had oily residue on the IAT.



That was also when that filter was new. So I may have done you a favor and sucked all the extra oil from the factory out of it.



Just for curiosity I may yank mine today to see how it's done in the last 25K miles.



Garrett

 

[Gary - K7GLD]

Let us know what you find Garrett - I haven't had the slightest signs of oil with the K&N I got from you - at least not at the inlet to the turbo or that general area - as you suggest, you had probably already sucked all the excess oil out of the filter - thanks... :-laf :-laf



OTHERWISE, *I* sure can't see what would contaminate the IAT without an EGR or exhaust brake setup - at least in relaticely short mileage...



Unless possiby there might be "weepage" of oil over a period of time from the turbo seals?

 

[Big White Beast]

Clean as a whistle again.......

Shot it with some carb cleaner anyway and put her in. 4 minute job tops.



The funny thing Gary, is that I never saw any indication in the turbo or the inlets either. It was only after I yanked the IAT. Could be totally unrelated, I just wasn't willing to chance it. Who knows!!



Glad the K&N is working for you, I would have hated to throw it in the trash.



Garrett

 

[Seed Guy]

A trick on gassers is to move the IAT to a cooler location that reflects the actual temp of the ambient air and not the air that is in the intake. By doing this you are convincing the computer that it is colder outside than it really is and thus you get more fuel. And we all know that fuel=power. No claims on the ISB. And i have no idea extactly how the ECM uses the IAT in a Cummins but it is some brain food for you guys.

 

[GeneralMachine]

MHO

Gary, I think the answer is valve overlap, and dexceleration. Harv

 

[jman]

I am having a surge after cold starts and it stops after the grid heater stop cycling. It isn't the same noticable pull on the engine you hear as the heaters are cycling either. They are way to frequent. I was told to try cleaning the MAP sensor and the IAT sensor to see if this would help. It is only doing it when the engine is cold. You can start it a hundred times during the day and it never does it. If it is plugged in it doesn't do it and the grid heaters are even cycling then. Only after it has sit for I'd say 6 to 8 hours and the "wait" light stays on. I am baffled at this one, but it did start after I installed my MegaCannon and I did have some oil on my turbo fins. I have since removed it until I get to the bottom of this problem. I have even eliminated the EZ from the picture as it is sitting in the garage right now. :{ :{ Does anyone think I have some dirty sensors and it is messing with it when cold? I'm clueless right now and so is everyone else I've discussed it with.



Any thoughts?

 

[John Berger]

Originally posted by Behr

John... . did you notice an improvement in your fuel economy once you cleaned it... . ??



I was debating on whether to clean mine or just buy a new one... .



I saw a post somewhere that showed the Ohm readings with temperatures... ... could be interesting to throw an Ohm meter on and take a few reading... before and after it was cleaned... ...



Also... do some of these trucks have EGR valves and some don"t... ???

Oh yeah. Almost 2 miles per gallon and that's figuring it based upon fuel pumped in, not by the overhead console numbers. I don't doubt that using an exhaust brake may have a direct impact on how quick the IAT sensor gets dirty, but I've only had my e-brake on the truck for 3 weeks. The Amsoil filter could be the culprit, but I've had it on since July of 1999. I only started noticing a decline in fuel mileage this past November. As far as I know, EGR is a requirement on late model year trucks in California, Massachusetts and one other state that slips my mind at the moment. In 2004, every Dodge Cummins engine will have EGR.

 

[Gary - K7GLD]

I live in California - neither ny '91 OR my current '02 have any EGR equipment - my brother in law and HIS brother in law each had '95's, one had a catalytic converter - the other did not - essentially the same truck - don't think either one had any EGR equipmemt...

 

[Ramtough]

On your advice - I went to remove my IAT sensor yesterday - the largest socket I have is 1". It looks like I'm going to need a much larger deep well socket to get this thing out. Can anyone tell me what size I need?

 

[NETim]

21mm

OK, after reading through this thread, I decided to look at the IAT on the truck.



To pull it out, I used a 21 mm deep wall socket. I also had to use a 3" extension on the rachet. You'll find that the dipstick tube is perfectly postioned to nearly reach the infamous PITA status. As it is, the dipstick tube is just merely in the way, but presents no real problems. Therefore the job does not achieve full fledged PITA status.



Only a nudge was needed to break the IAT loose. I turned it out by turning the socket with my fingers. Also replaced it with the socket and finger method. I just snugged it up with the rachet. It wasn't very tight when I removed it, so I saw no need to get serious on the rachet.



The IAT was pretty clean at 18K miles on the rig. No exhaust brake in use as of yet.



The IAT resides inside a white plastic cage so don't use a cleaner that will kill plastic. The IAT itself is just a thermistor. Nuthin' exotic.



The picture posted earlier on the thread provides the location of the IAT.



Tim

 

[R-N-R]

I checked mine today and with the exception my truck having 10k miles and using a 13/16 socket, it went as Tim described.

 

[stg2500]

Can the IAT and MAP sensors be cleaned the same way. It sounds like carb cleaner should do a good job.



Are there any other sensors that should be cleaned at regular intervals.



I am approaching 55k and have noticed a slight drop in fuel economy.

 

[John Berger]

Gary, I stand corrected on the EGR requirements in California. I thought I read it in the TDR or this board. So much for thinking ...



next time I'm just gonna speculate.

 

[Gary - K7GLD]

"next time I'm just gonna speculate. "



Shucks - if it wasn't for speculation, conjecture and wild guesses, *I* wouldn't have much of anything to post here... :-laf :-laf :-laf

 

[Scrappy]

iat relocation?

Has anyone done this? I am thinking that it would also make the 3cyl. mode more effective, making it engage more quickly and more often. what is the downside of this mod?