Air filter condition and IAT

[aldive]

I am curious avout the IAT as related to the confition ( dirty or not ) of the air filter.

I am running a test with a 15k mile use on a KKM vs a fresh cleaned/oiled KKM to its effect on IAT.

Half of the study is completed; the dirty filter part. Resulta should be available tomorrow on the clean filter.

 

[mosinman]

My guess would be that there is no effect. I would think if you clogged up the air filter enough to seriously restrict airflow the IAT could read a little warm. However, other driveability problems due to your motor gasping for air would be noticeable long before your IAT caused problems. What are you testing? voltage signal?

 

[aldive]

I am testing actual IAT via an OBD II scanner.

 

[mosinman]

I mean to buy a scanner someday but the Autozone right down the street will scan me any time I want for free. Still, I would like one for myself. Oh well, looking forwards to your results.

 

[aldive]

Originally posted by Gimp
But, on the flip side, we early model guys can remove our fuel filler cap to gas up while the engine is running and not set off the check engine light (and then have to run a series of open/close loop cycles to clear it up).
Note: I do not fill up with my engine running. I was just pointing out that I could do it and not get a check engine.

Or use our nifty scanner to clear the code......

 

[Robert]

Originally posted by Gimp

That's pretty cool that you guys with OBD II can ride down the road and get a running data stream. We OBD I guys can't do that kind of thing.
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Yes you can. Our AutoXray also provides real time monitor data for EEC IV as well. I use it all the time on my Wife's '93 Sable.

Originally posted by Gimp
. . .But, on the flip side, we early model guys can remove our fuel filler cap to gas up while the engine is running and not set off the check engine light (and then have to run a series of open/close loop cycles to clear it up).Note: I do not fill up with my engine running. I was just pointing out that I could do it and not get a check engine.

So can we, the CEL won't get set off until it detects a leak at the gas cap twice in a row with a minimum of 6 hours in between.

 

[Robert]

Originally posted by Gimp

Cool. How do you hook up to hers to do that? My Exploders have a plug under the hood by the power fuses that you have to remember to put back in its place or it will flop around and get wet (or worse yet, lie on something hot and melt).. . .

The EEC IV cable is about 6'-8' long which is more than long enough to plug into the port under the hood and through the door jamb, leaving several extra feet to plug into my scanner.

Originally posted by Gimp Chryslers don't give you that much of a break. People I know that work at both the local Chrysler dealer and the local Dodge dealer tell me that people STILL come in and complain that they got a few dollars worth of gas in a hurry with the engine running and then got a check engine light - 6 years after OBD II became the standard. I've seen it before at the gas station, too. Somebody would be filling up next to me with their engine running and during that little bit of time their check engine light would illuminate. Thankfully, I haven't had that experience (yet).

Chrysler must have a manufacturer specific DTC for when the gas cap is loose. The Generic OBD-II protocol specifies the condition that I mentioned above to set off a P0455 code which is the code that was set off on mine when my gas cap failed.

As a side note, I stopped in at AutoXray's factory last night on the way home from work again to talk to the Owner/CEO and he told me that some manufacturers have started incorporating OBD-III on their '03 model years. The AutoXray is the only scanner currently available that is already capable of retrieving OBD-III codes. It will require a new cable since the pin-outs are different. Not even Ford's NGS Star Tester is capable of that. So it looks like all I'll need to do is buy a new cable and software enhancement when I buy an OBD-III equipped vehicle.

 

[aldive]

IAT Test results

The test that I did compared the IAT with a dirty KKM filter vs a clean/oiled one ( see Dead Link Removed for the cleaning ) at various speeds.

The data collected were ( 1 ) IAT ( Intake Air Temperature ), (2) vehicle speed as determined by GPS ( Garman GPS III Plus - Dead Link Removed ), (3) ambient temperature ( determined by the Explorers overhead temperature display ). The IAT was determined via an OBD II scanner (http://www.autocheckup.com/default2.htm )

I tested at idle ( from cold start ) for 15 minutes, idle for 15 minutes after the at speed trials, at 40 MPH, 50 MPH, 60 MPH, 70 MPH and 80 MPH. Each speed was maintained for 10 minutes using cruise control prior to the reading.

Each test was conducted with a 15k mile old KKM and a freshly cleaned/oiled KKM ( http://www.kustomz.com/ ).

Dirty KKM Clean KKM
Ambient speed IAT Ambient speed IAT
90 0 135 F 89 F 0 132 F
90 40 100 91 40 99
90 50 97 91 50 97
91 60 94 90 60 94
91 70 93 90 70 94
91 80 94 90 80 93
91 0 hot 147 90 0 hot 145

Conclusions: The IAT is not influenced by the air filter ( clean vs dirty ). At vehicle speeds over 50 MPH, IAT is only a few degrees above ambient, indicating excellent air flow to the intake

This data should put to sleep the thoughts that a cone filter will be influenced by under hood temperature while driving..

I wonder how this compares to a stock airbox/filter system and to some of the homemade “cold air” systems?