IAT climbing way up at idle..

[leamangriffin]

LS 5.3 swap in a 98 Tahoe. Still working out the kinks to get it running right. I have sloppy 02s that i am replacing waiting on new ones to arrive.
The problem is my IATs. for some reason they climb way up there at red lights and such. like 120+ degrees. and it is night time and 55 deg outside. engine is not overheating.. around 190-195. as soon as i get moving they fall back down.... when they are up high my truck seems to be a bit sluggish. but no misfires... any ideas?

no tq mngt 1.3 pe ramp in.hpt
drive home 55 deg outside.hpl
Attachment 47579

[G-Body]

Where are you pulling your air in from? How close is your MAF/IAT to your exhaust. By your log it definitely looks like your IAT gets heatsoaked air low speed / idle. My first thought is that your engine compartment does not have a lot of airflow and when you go slow your intake starts pulling in that hot air. It could also be that the sensor is right up against your exhaust and gets heatsoaked from that.

[5FDP]

Not to sound rude but why does this bother you and what don't you understand??


You arent moving, so there is not air flow through the front grille, vent radiator. So all that heat is just going to stay in 1 place and build up quickly, hence the higher spikes in intake temps.

If you placed the MAF closer to a fender well like the stock air box on a GM, the intake temps will stay lower for longer.

The reason it feels sluggish is because above 100º or so intake temps, the computer pulls alot of timing out. You can view that table and adjust it if you wish.

[leamangriffin]

i guess i should have prefeaced that my intake is almost in the stock location and I have dual 15" flexalite Electric Fans... there "should be" a ton of airflow in my engine bay even at idle.. and i verified my fans were on when the temp rose. I get it rising a bit at idle.. but 120+ degrees? on a 55 degree night? within 2 minutes of stopping?20141103_192729.jpg

[5FDP]

I just have a feeling that the fans kinda force the air into the front of the motor and then it bounces off to the side and right into the filter.

At a guess, if the filter was directly behind the headlight it would stay cooler for longer.

[mbray01]

If you want to be able to tune and make that engine run good, you need to ditch that whole setup and get one that seals to either the fender or the front radiator support. That intake is sucking only hot air, extremely inefficient!!!!!

There is a reason that the factory air box is not open to under hood air and sealed to pull outside air.

[PICNIC_GEORGE]

I can see there being a lot of heatsoak and underhood hot air at low speed going on with that setup. That filter is pulling air from right above the header. A better intake and a heat shield will probably help a lot.

[leamangriffin]

Ive got to start prefacing better haha. I used to have the Intake up behind the headlight and that is when it started doing it, so I moved it back to its current location... Anyway I built a cold air box for it and Installed it. Havent had time to test it out yet but im hoping it will help..

[adamyarbrough]

I have a bone stock 04 SWB with a stock swapped engine. My IAT and ambient temp on the rear view mirror both rise considerably at idle. I know it?s airflow problem, now thinking the radiator is plugged just enough at the bottom to build excess heat without overheating. Those things are small from the factory.