blt91RS

iTrader: (3)

Hey guys, I installed a Fast 90 and a 92mm Nick Williams TB last week and I must say I am extremely impressed. However, the throttle pedal is very stiff ONLY when you first depress the gas pedal. Otherwise it operates fine and does not stick open or anything. It is just the initial opening of the throttle that requires a good firm push. Any ideas what is causing this? The blade itself moves freely when I open it from under the hood so I know it is not coming into contact with the intake.

BlackDuk98

iTrader: (34)

I had that problem on the initial depression of the pedal. That first moment seemed tougher then the rest. I noticed that the tb blade was grinding on the side of the tb itself. To the point where there were gouges and metal dust. I had to tear it apart and sand everything to remove it. It's much better now but I still have the problem. Had it apart 4 times now and sanded spots where it was rubbing, made sure blade was centered when I put it back together (equal amount of light showing around all edges) and it is still there. If I let off the gas really slow, it hangs up and keeps the car idling at 1700 rpm. Have to tap the pedal fast to get it to release. I have to get on it a 5th time now so I can get the lower rpm tables tuned on my car. Couldn't even finish when I was on the dyno.

Thing I noticed is that there is a minescule amount of throttle shaft play. If you pull the shaft side to side while opening and closing the blade, you can feel it grinding a bit. With the cable on one side of the tb and pulling / releasing it a lot, I think it moves the throttle shaft to the side a bit causing the play to occur and keep my problem always there. Just what I have noticed. Btw, mine is also a NW92.

blt91RS

iTrader: (3)

Very interesting. You would feel the rubbing when you opened and closed it from under the hood as well?

BlackDuk98

iTrader: (34)

not currently since the last time I sanded it, but driving and idling up to a stop light slowly, the rpms still hang there till I tap the gas. Pulling everthing off and just looking at the throttle body, I will see a slight shine to where the blade has made the inner tb smooth, but I won't feel it. Another way to notice it is to pull your tb off and litteraly put it to your ear and move the blade / shaft a bunch. You will hear it for sure.

Scoobie

iTrader: (8)

I had this issue with a NW 90mm TB back in 2006. Just sanded the inside down a little to avoid the rubbing issue. Car would idle high if I put it in neutral and coasted to a stop light. Very nice piece in general, just hardly touched. 10 minutes and Problem solved.

ramairetransam

iTrader: (18)

it sounds like something you shouldn't have to do after spending a fair amount on the throttle body .

thunderstruck507

iTrader: (18)

First time I've heard of this issue with the Nick Williams. New or used?

It is a common problem with the Fast brand tb. Sand it and you should be fine

BlackDuk98

iTrader: (34)

for me it was brand new. 2 other locals I have talked with have experienced it with theirs as well.

When I first purchased mine I didn't notice anything. I was sitting on the couch mocking it up to my intake one night and was just admiring it and opening it / closing it and it seemed fine. I did it some more and it started to rub and get tighter, then the aluminum actually started to gouge the sides a bit, Gauling I think is the word.

I still had it sticking a bit today so I pulled the lid and maf and just had the tb to look at. In one corner there was a small line where it looked like the blade was rubbing. It wasn't. I wiped it with my finger and the aluminum has no new wear showing at all. It appears to be some oil residue that I guess gums up with the heat and then due to the close tolerances between the blade and the tb, makes it stick a bit. I hardly get any oil in the intake at all so it's nothing crazy, just a slight mist enters it.

A hypothesis I had previously was concerning the expansion / shrinking of the tb -vs- the blade during heating / cooling causing the problem but I haven't heard of many people with any problems which is why I chose this tb.

blt91RS

iTrader: (3)

Mine was used. I'm gonna sand it down tomorrow and see if that helps at all.

thunderstruck507

iTrader: (18)

For what it's worth, my Fast tb would work fine on the bench, but once bolted to the intake would stick.

It has recently started getting a little rough again, not sure if its build up of maybe the blade has shifted itself some miniscule amount.