IAT and O2 sensor locations


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I'm sure most of you have more advanced setups than I do, but I'm questioning if the sensor locations for IAT and O2 are best?

I have a IAT in the factory location, and it seems to be operating fine, but I have a reoccurring issue upon hot start that the engine almost sounds like its missing on 1-2 cylinders. If it give it a minute or 2 it will smooth out, but if I don't wait it will hesitate and sometimes die with just the slightest bit of throttle input then letting off. It could just be the tune needs more work, but I wondered if maybe the sensor was just heat-soaked and once it's run for a minute and clears up the sensor is cooling down. When I had the FMS Mass-Air kit on the truck the IAT sensor was relocated to the airbox. I'm once again using the factory intake location with the Pimp.

Also, while driving I'll see drastic swings in AFR while just cruising steady speed, but holds pretty solid AFRs while accelerating. I have the O2 sensor in the stock location little crossover tube and I'm wondering if there just isn't enough gases flowing over the sensor to give stable readings during light throttle cruising. Once I get the turbo kit on hopefully that won't be an issue, but wondering if I should more the sensor to a better location for now until then. Just wondering if it could cause possible tuning issues.


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You do not need to move the IAT as there are a few knobs to turn for hot start. A data log would be best though before you start tuning so you know exactly what's going on. Same for the A/F swings.

FMOS Racing

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I'm one who believes that the IAT needs to be where it is. I also have some lean conditions on a hot restart - not quite as bad as yours, though. But it clears up as soon as you get a few RPMs in it and the ACT becomes realistic.

Once air is moving across the sensor, it's a true look at what the intake charge temperature is, especially at WOT, which is important because of the way you'll want to tweak timing for boost.


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My hot start took a little extra effort aswell. If it sits for a few minutes (getting gas, running into a store, ETC) it seemed to be the worst as the IATs are quite excessive and the ECU thinks thats the air. I played with after start enrichment and crank fueling and mine seems happy now. I usually like to let it idle for 10-15 seconds after starting before taking off for all those time delays to fade out but I don't really need to anymore.