Are these the same? I was reading online about a kit to relocate this sensor from the lower intake manifold to the airbox... Are they different terms for the same thing, or is there a difference?

The manual isn't really specific... if they are different, which one does my 91 5.0L have in it?

 

In my day, they were different, ECT, engine coolant temperature. ACT, air charge temperature>

 

This is what I thought, but I'm not getting really accurate info from the manual, and this kit online got me wondering - it seems to be taking the ECT from the manifold and placing it where the ACT would likely be?

Not the end of the world - I'm just hoping to learn something!

 

The ECT wouldn't work in the airbox. Some cold air intakes don't have a spot for the ACT, maybe the kit moved it from the tube to the airbox?

 

I dunno... the thing specifically mentioned moving it from the lower intake mani to the air box. That's where I got confused - but there wasn't a lot of detailed tech info on the site.

 

I don't know how that would help, unless there's some performance secret that this works for. The ECT wouldn't be able to read the engine temperature and the computer would keep it in closed loop, richening the fuel mixture.

 

The ACT is the only sensor that has had the airbox used as an alternate mount location in which case the sensor used has a plastic probe head rather than brass over the therrmsistor. Relocating the ECT there would result in the engine remaining in perpetual warm up mode. I suppose if you had a hairdrier w/ a reeeeal long extension cord......nevermind!

 

if the engine stays in perpetual warm up mode, does it run richer? I'm thinking that may be some of my problem with a very cold thermostat. I bought a stock replacement one, just haven't installed it yet.

 

Yep, that's the que for the PCM to get off it's a**.And continues to run rich while contaminating the o2 sens w/ deposits and fast tracking the demise of the Cat. Get a Mr. Gasket performance thermostat The shorter time it takes in reaching op.temp.(and PCM enforcement of a 14.7:1 air to fuel ratio once it enters closed loop function) will more than make up for the initial higher cost.