Has anyone been able to fix this issue beside replacing the entire throttle body?

I have a custom setup where I used a B-series Blox 74 mm TB on my NSX. There is something that is catching on the last 1/8 inch, so my car won't idle below 1500 RPM. I can physically get in there and push it back so that it does idle at 900 RPM, but that is obviously not a real world solution.

My hunch is that I will have to take apart the shaft that the throttle plate is attached to and sand/machine it down somewhere, but I'd like to know what I'm getting into (if someone else has done it before).

Thanks.

 

Obviously off the car take a file and very gently taper the edges of the throttle plate on the top and bottom. I say very gently because you don't want to take off too much, just enough to stop sticking.

 

yes. the plates are usually brass, which is very soft.
TB's are typically machined at room temp of course, and brass and alum have different expansion rates. this is why when they stick, it's usually only when the engine is heated up, but not stick when the engine is cold.

the first thing I would try though is just proper positioning of the plates. to do this, loosen the screws holding the plates on while the TB is full closed. make sure the shaft is at full closed position, try jiggling the plates around if they will at all, then just re-tighten the screws making sure the shaft is at full closed position the entire time.
reason I suggest the above is because the plates need to be fully centered to close properly, and if they aren't they will drag on one edge and stick. and there's usually some wiggle room in the screw holes, allowing the plate to shift a bit when screws are loose, allowing for placement adjustment

 

Many of the throttle bodies I have seen have staked on screws that can't be removed. I tried that on an older omni unit and broke one of the screws with very little effort. Examine them closely before you try this.

 

Do you mean the screws on the shaft that the throttle body plate is riding on?

 

yes, the screws that attach the plate to the shaft.
most screws are staked, so take notice of the post above mentioning that. I've never had an issue with staked screws getting damaged, they loosen just fine for me. but you should still heed the warning of course.

 

Update:

Took off the throttle body, and saw that the blade was way out-of-round vs. the bore.

Took some 50 grit sandpaper and sanded around the bore, then finished it with steel wool.

It cleared up 90% of the sticking problems.

It still sticks when the car is really hot, I'm assuming that is thermal-distortion/warpage.

As an FYI, I was at my friend's warehouse and we took out (for comparison) the following:

(a) Skunk Alpha 70 mm - super smooth operation
(b) Skunk (billet) 70 mm - smooth
(c) Skunk (billet) 74 mm - you could already here it catching

But none of them felt or sounded as crappy as the Blox unit. They really need to step up their QC.

 

why am I not surprised?

I think everyone in cali should collect all their defective parts and leave at their front door during BLOXFEST

 

ive been using omnipower tbs for about 4 years now with no problems

the ones from phearable.net. their cheapest ones to be specific.

many people( including me) do not know that throttle plate on most of those throttle bodies should not close all the way

I thought so too when I adjusted my throttle plate shut and was having idle problems

phearable.net emailed back to me saying that they are set where they are for a reason and I shouldn't mess with the adjusting screw...
so I set it back to where it was


plus:
how hard is it to actually pull off the intake pipe and clean the damn throttle body at least once a year.

or maybe every 6 months