Throttle cable replacement

[fastfwd]

So a few weeks ago I pressed the NSX throttle pedal for probably the three-millionth time and the cable snapped.

I was in the mountains with no tools, and home was uphill, so I wedged the throttle open with a stick jammed into the linkage and limped home that way. Found the Dutch guy who makes replacement cables, bought one, and now I'm finally ready to install it.

Anything I should know that's not in the service manual?

 

[Blazed.]

Can’t recall what all is in the manual but the cable basically routes through passenger side to center tunnel to driver’s side to pedal. You’ll need a lot of patience to get the new cable into the throttle pedal. I recommend removing the driver’s seat; makes life easier for sure. ASmotorsports cable sheath is much thicker than oem and should last for the life of the car.

 

[Honcho]

Aw man what a bummer. Most of the time a snapped cable is due to someone trying to remove it in the past who doesn't know to do it and damaging the strands. It's a shame you have to pay for someone else's ineptitude, but I'm glad you made it back safely.

Installation requires removing the interior of the car- carpets, seats and rear trim panels. My advice is to fit the grommet in the firewall before connecting either end of the cable. You will find it difficult, but possible to connect the head at the pedal due to the tight access. Removing the old cable should help you figure out to to feed it back in. Routing across the engine and connecting at the throttle body is the easy part since all of the retaining clips are obvious and easy to access. Set tension via the service manual method.

I should also buy one of Adnan's cables for a rainy day...

 

[fastfwd]

Can’t recall what all is in the manual

Very little. Just the adjustment procedure and the obvious routing on the engine side of the firewall.

I took your advice and removed the driver's seat as well as the passenger's. Glad I did -- looks like clipping the cable into the pedal will be difficult even with the seat out. Would be impossible with the seat in.

 

[fastfwd]

Aw man what a bummer. Most of the time a snapped cable is due to someone trying to remove it in the past who doesn't know to do it and damaging the strands. It's a shame you have to pay for someone else's ineptitude, but I'm glad you made it back safely.

Thanks. In my case it seems unlikely that the strands were damaged that way -- the only person who's worked on the car for the last 20 years is Don Lam, and it's been a long time since it's needed any work that requires unclipping the cable anyway.

But I have put 300K+ miles on my car, so maybe I just wore the cable out somehow. I'll take a close look once it's removed; maybe there'll be some visible clues as to what exactly happened.

 

[fastfwd]

Ok, so now I've got everything out except the passenger-side console carpet. Is there a trick to removing it?

The manual shows what look like keyhole-shaped clips on the top edge of the carpet -- is there a way to get them to release without removing the center console?

Also, the air vent that comes through the carpet in the passenger footwell seems very solidly held in place. I don't see any screws holding it (although there is an empty screw-sized hole in it) -- how does the carpet separate from that vent?

 

[fastfwd]

Well, that was the most miserable repair I've ever done on any car.

 

[NZNick]

There is a Lap of the World video on YouTube on this subject -

 

[fastfwd]

There is a Lap of the World video on YouTube on this subject -

Thanks. I found that and it really helped with those carpet clips. But the video ends with the removal of the cable, so there's no information about the installation.

FYI for anyone who's doing this repair in the future: The AS Motorsports cable does not have the reduced-diameter section in the threads at the engine end, so it's VERY difficult to install the engine end of the cable if the pedal end is already installed. Do it the other way, engine end first and then pedal end.

Also, the spring clip at the pedal bracket can be removed more easily than is shown in the video: Instead of trying to hook onto it from above, push a dental pick (or an awl, or maybe a tiny screwdriver) up through the slot from below to slide the clip free.

 

[Honcho]

Thanks. I found that and it really helped with those carpet clips. But the video ends with the removal of the cable, so there's no information about the installation.

FYI for anyone who's doing this repair in the future: The AS Motorsports cable does not have the reduced-diameter section in the threads at the engine end, so it's VERY difficult to install the engine end of the cable if the pedal end is already installed. Do it the other way, engine end first and then pedal end.

Also, the spring clip at the pedal bracket can be removed more easily than is shown in the video: Instead of trying to hook onto it from above, push a dental pick (or an awl, or maybe a tiny screwdriver) up through the slot from below to slide the clip free.

Nice job! And good advice for future owners. I'm sorry I did not get back to this in time, but it's easier to get the center carpet out if you remove the center console . You can use needle nose pliers to grab the plastic tabs and lift them off the screw heads on the dash panel. The carpet pulls right out this way.

Edit- I wonder if it's worth grinding the flat on the threads with a dremel to replicate the OEM recess.

 

[fastfwd]

I wonder if it's worth grinding the flat on the threads with a dremel to replicate the OEM recess.

Seats and carpet are still out of my car, and I'm considering doing exactly that, because otherwise it'll be impossible to disconnect the cable from the throttle body in the future.

Sigh.

 

[Honcho]

Seats and carpet are still out of my car, and I'm considering doing exactly that, because otherwise it'll be impossible to disconnect the cable from the throttle body in the future.

Sigh.

Smart man.

 

[fastfwd]

So I didn't grind down a section of the threads, because Don had a better idea.

First, here's the problem that needed to be solved. This is the threaded adjuster at the engine end of the factory cable, next to the bracket that it fits into:



Note the reduced-diameter section of the threads, which allows the adjuster to fit through the slot in the bracket. Once it's in, the adjusting nut pulls the thicker threaded part into the bracket, where it's held in place, partially by the clamping force of the adjusting nuts, but mostly because the threaded section is too thick to pop back out through the slot.

When you WANT to remove the cable from the bracket, it's easy -- you just loosen the adjusting nut until the skinny section is under the slot, then lift it out.

But the AS Motorsports cable doesn't have that skinny section. The whole end is threaded:



So it can't drop into the slot. Which is a problem, because the only easy way to connect the cable is to attach it to the throttle first, while the adjuster is out of the bracket, and then drop the adjuster into the bracket afterward.

I couldn't do that, so I had to feed the cable and adjuster through the bracket and then attach the cable to the throttle. It was a real struggle. And once I was done, it was clear that it would be another struggle every time the cable had to be disconnected for service.

Also, the adjusting nut wasn't holding the bracket in the middle of the adjuster where it should have been. Instead, it was all the way at one end. So I could grind a reduced-diameter section into the threads, but I wasn't sure where in the threaded section would be a safe place to do that.

Don's solution -- obvious now -- was to leave the cable alone, and replace the bracket instead.

He made a new bracket with a straight-sided slot that the thick AS Motorsports adjuster could drop into, but with ears on one side of the slot to hold the adjusting nut in place (and thereby keep the adjuster from popping out of the slot).

It works great.

Unfortunately I don't have a photo of the bracket before it was installed, but here's the view from above of it in the car:



And here's the view from the side:



Hope this idea is helpful to future readers who might need to solve the same problem.