What exactly is this part called?
 

I need to repair or replace the air intake hose on my '89 4L Pioneer. But I can't find any info online, such as what it's really called, or even any pictures that accurately look like my engine.

It's about 2" in diameter and runs FROM the air cleaner and down underneath TO the intake manifold (fuel injected), attaching somewhere down out of sight. It's constructed of a papery material around a spiral wire. There is a heat shield on the portion that touches the power steering pump.

For now I've patched it with duct tape and silicone. This is not an acceptable solution to me.

Please suggest what to call it so I can search beyond the wrecking yards as they don't have one. Thank you.

That just there to help engine warm up . Called heat riser tube.....

Correct - and the replacements will be Mylar, not fabric. Measure the OD of the nipple, it's the same size on both ends.

The under end passes to the "choke stove" that is formed around the exhaust manifold. The purpose of the thing is to preheat the air going into the engine on cold (and cold-weather) starts.

Is it necessary? Apparently, this is where the smog "techs" and I agree - I usually get a handwave on the thing being missing on my 88. It's a holdover from carburettors - it was useful for carburetted engines, but it's not necessary for fuel injection (it was meant to help prevent carb icing and to encourage fuel atomisation/vapourisation until the engine warmed up, and to assist if the intake air temperature were to drop.) Since the throttle body on MPFI engines is dry, icing isn't much of a problem. Since the fuel is dispensed in an atomised condition by the the fuel injector (and sprayed in through the intake port before it gets a chance to puddle or condense,) assistance there isn't really needed, either.

No impact to emissions or fuel economy if you run without it.

That's funny, I broke two things on my Jeep today and I've been told neither thing is necessary. What are the chances? I broke the knock sensor and this "pre-heat" tube or whatever it's called.

BTW, you need the 2" tube for your '89 Renix. I got a replacement at O'Reilly's and it fit great on the air box but I had a heck of a time getting it on the header fitting. I finally gave up until tomorrow... until I saw this. Now I'm giving up permanently.

These are great answers, I learned what that thing is! Now another question:

If I remove it, will I get heck from the smog techs next time I go in? They have a checklist of required items and connections and who knows but that this might be on it.

Reread my previous post - I think a lot will depend upon the techs involved.

If you need to replace it after all, it's a low-buck part. It's just a pain to get the lower end on, sticking it on the choke stove. Putting that down, and then twisting a bit of wire around it to retain it while you stretch it to the airbox shouldn't go amiss.