Gizzard Puke & throttle cable tension

[Nick Graves]

I've just carried out one of my favourite tuning measures; cleaned the throttle butterfly & venturi with choke cleaner and removed a huuuuuge amount of play from what there is of a DBW throttle cable. A tiny spot of silicone lubricant spray on the throttle cam (cable's plastic sheath, actually) too, for extra smoothness.

What a difference! I'd swear I've found 10 BHP (although that's probably an illusion - but it's no longer only as fast as my S2000!) the whole thing is much smoother on/off the throttle, seems to run sweeter and of course, the extra accuracy has massively improved the handling such that drifts are a beautiful as they ought to be and it all comes together far more.

I thought I could feel the butterfly sticking off idle and it was 'graunchy' across the range of travel. Quite how you do that with a DBW, I dunno, but someone ought to tell other manufacturers. The feel truly is superb now.

Honestly, it's a simple job and well worth the effort if yours hasn't been done in a while.

[Thunder]

I made the same thing, I cleaned the air tubing and the butterfly with grease-remover and cleaning driving and lubricated the cables with grease lithium, the result is fantastic, with what cleaned your air tubing and the butterfly?

[AR]

Probably just crud accumulated over time.

[Nick Graves]

I made the same thing, I cleaned the air tubing and the butterfly with grease-remover and cleaning driving and lubricated the cables with grease lithium, the result is fantastic, with what cleaned your air tubing and the butterfly?

Avec du:



ou quelque chose similaire.

[WhyOne?]

I've just carried out one of my favourite tuning measures; cleaned the throttle butterfly & venturi with choke cleaner and removed a huuuuuge amount of play from what there is of a DBW throttle cable. A tiny spot of silicone lubricant spray on the throttle cam (cable's plastic sheath, actually) too, for extra smoothness.

.................

Honestly, it's a simple job and well worth the effort if yours hasn't been done in a while.

Is it possible, in idiot-laymans terms, to explain precisely what 'effort' is required please Nick?

[Thunder]

Avec du:



ou quelque chose similaire.

Thank you :-)

[Nick Graves]

Is it possible, in idiot-laymans terms, to explain precisely what 'effort' is required please Nick?

Well, I can do it!

There's a black box on the RHS damper turret. A 10mm bolt back & front hold the cover on. Remove it & you'll find the throttle cam on a rheostat. The throttle cable is secured by 12mm locking nuts. On no account spanner the outer one as there's a boss underneath the lock it from turning. Crack the inner one & thumb it to the end of the thread. Pull the cable sheath until the cable's almost taut, spin the outer nut down to the boss & then re-position the cable & lock up the inner nut. The cable oughtn't be tight like a guitar string; there ought to be a little play before the cam starts to turn. The cable gets shorter in the winter...

A little Holts Silicone & rubber lubricant (ot interior dressing!) on the plastic cable sheath (if you open the cam by hand, you can pull the cable off it) ought to help too. Reassemble.

Accessing the throttle body requires removal of the accordion; slacken the two jubilee rings and the 10mm nut which attaches the breather pipe to the TB. You can remove the air box cover, but it's not absolutely necessary. I just squeezed the accordion down & forward so I could see the brass butterfly. Place a cloth underneath to soak spillages.

Do not follow the destructions on the spray can: running the engine seems dangerous. Spray a little round the butterfly & let it soak in. Use a plastic handle to push the 'fly open at the bottom & spray the other side & where it seats. You need to wipe off the carbon deposits from those ridges, using a cloth. Small hands or a gyneacology qualification probably helps here. Giving the stuff time to work and to evaporate is the key.

You don't want to use the whole can, or you will hydrolock the engine. So don't go nuts.

Once you're happy the 'fly is moving easily, re-assemble carefully & give it a little vapourisation time before attempting to start.

You will have flooded the engine, so it will need a long crank before it splutters into life & settles down.

It ought to drive like a new car now.

I'm convinced doing it regularly cleans the burnt oil/combustion crud from the plenum butterflies and the backs of the inlet valves too, which is why it seems to run sweeter.

If it's too daunting, you can always bring it 'round here!

EDIT: be careful with tins of choke cleaner with a push-in type extension pipe. I once shot the extension down the Prelude's gizzard and had to dismantle it to fish the pipe out of an inlet port! It's got variable-length tract butterflies & stuff just like the NSX...

[Kaz-kzukNA1]

If you are carrying out this process, as Nick mentioned, please remember to leave some slack/play in the throttle cable for both DBW and non-DBW model. It is important from the heat, vibration, idle rpm, etc point of view.

On DBW model, there is a specific distance mentioned on the manual on how to set the lock nut for the throttle cable and if you go too far, it will affect the idle control.

It is a good idea to clean the throttle butterfly and surrounding area once a year. I think the TH butterfly on Nick’s car was showing the typical sticky butterfly on most of the NSX. By the way, you won’t gain any power unfortunately. There has been extensive study carried out on the throttle body diameter - power by the manufacture/NSX specialist in Japan and you just recovered the throttle response…

For DBW model, the cleaning process is quite simple but please note that on some cases, you may need to adjust the idle rpm depending on what was done in the past before the cleaning process. This will require specific procedure to be followed in order to achieve the correct idle rpm.
On DBW model, there is no EACV or idle air port on the TH body and we are relying on purely for the tiny air gap between the TH body and the butterfly controlled by the stepping motor.

For non-DBW model, the key for the cleaning process is to target the cleaner to the idle air port, EACV and Fast Idle valve. If you look into the TH body from the air box side, you will see small hole at about 11 o’clock position. Addition to the Nick’s procedure, please shoot some cleaner in there. For this reason, you will need to keep running the engine during this procedure.

For any of the above process, please never use the brake cleaner.
You will be carrying out the process on warm/hot engine parts and some of the brake cleaners are flammable as well as it may produce hazardous gas.

Happy cleaning.

Regards,
Kaz

[Nick Graves]

Just to clarify Kaz' point:

Cleaning the TB improved the handling(!)

The NSX has a very short-travel throttle pedal and there was probably 1/2" or more lost motion on mine and I'm sure I wasn't getting WOT at full throttle. Hence the 10 BHP guesstimate.

[Thunder]

To clean the tube butterfly, I used a powerful grease-remover (degreasing before painting), then, I polished with of Belgom Alu, the result is very good, at the same time, I replaced the spark plugs and to clean the pads coil, lubricated all the cables with liquid grease with lithium, the idle was stabilized after ECU reset