Throttle body cleanup once a year, from now on.

[digisol]

Ok now I'm not slack with maintenance quite the opposite, the VS went OK and answered the throttle when tramped if needed.

So what you say, fair enuf, while changing the leaking rocker cover gaskets I had to remove the throttle cable setup to get access to the rocker cover under it and while there undoing the three 10mm nuts and removing the throttle cable part it seemed seemed a logical move to go further.

Not having done it since buying the thing it seemed it may be just a waste of carb cleaner but to my shock the inside of the body was full of crap and essentially restricting air flow past the butterfly, it had to be.

So after a clean of the 1.5mm of baked on black crud hidden behind the butterfly the thing now literally leaps to life at the slightest throttle and has close on 15 - 20% more off idle power hitting the speed alarm heaps sooner and with less throttle than before.

Why bother telling the converted you ask ? it's a safe bet that many others have not ever bothered to clean the sucker as I had not, because there was no apparent problem with the engine, after all it did work fine, above average.

Besides the added off idle power and much faster throttle response it dropped the idle 150 rpm and also dropped fuel use substantially as much less throttle is needed to get it up to speed.

It's now on my yearly list of things to do, after all the two 13mm nuts is not rocket science, and while at it clean the air flow metering block, a simple job definitely worth doing at regular service intervals.

:driving:

 

[Mk III the HSV]

Yeah it does make a difference if it has never been done before. 10 or so years of carbon build up is not really good for it. I did mine not long after I got my car, should do it as a part of the major service that you do when you first buy a car.

 

[hako]

I can't understand how the throttle body etc can have a buildup of carbon/dirt or whatever - unless the car backfires, there is only clean filtered air passing thru the throttle body. Does anyone know why and how this buildup of crap occurs?

 

[kopper69]

I did mine a few months ago while monitoring very closely and accurately my fuel usage. Even though I expected alot cleaning all that crap out I did not notice and difference in throttle responce and my fuel usage data did not support the fuel saving theorm. So it didnt really do anything for my car (Im not saying it doesnt work - just didnt do anything for my car). I still felt good about doing it though and would recommend it. We did go through this phase a few months ago, if people havent done it by now, they probably wont.

 

[Harvs82]

I can't understand how the throttle body etc can have a buildup of carbon/dirt or whatever - unless the car backfires, there is only clean filtered air passing thru the throttle body. Does anyone know why and how this buildup of crap occurs?

I think you will find its caused by the emissions gear. Crankcase vapours are recycled through the intake, around the throttle body, so the oily residue is the result...

Someone correct me if I am wrong though!

 

[hakhawk]

harvs is correct, theres (atleast on vn-vr) a hose that on my vn went from rocker cover to the throttlebody, before the butterfly, and vn s2 onwards i think is a pipe from intake manifold to throttlebody.

i removed mine when i got my new rocker covers, coz i didnt want to drill a hole in them, and it is still clean becuase of it, but i dont think the epa would be happy.

we're lucky with the vn-vr, stuff all emissions stuff, mostly controlled by ecu, the equivalent american version of the v6 has some serious emissions crap on it and the motors suffer as a result, due to excess carbon build up.

i think the vt went back to extra emission gear on the motor.

 

[hako]

I think you will find its caused by the emissions gear. Crankcase vapours are recycled through the intake, around the throttle body, so the oily residue is the result...

Someone correct me if I am wrong though!

I think you are correct.
Did a bit of reading: (from Gregorys) "If the engine is excessively worn and blow-by is at a high level, a small amount of crankcase vapour will flow back into the throttle body, irrespective of throttle position"
So this means the more worn the motor is, the greater the need for throttle body cleaning. Thanks and Regards

 

[quiksilver1]

how long does it take to clean?? cheers

 

[Harvs82]

how long does it take to clean?? cheers

Just a few minutes, spray it in, wipe and scrub the throttle body if it is really dirty, spray a fair bit into the idle control bit and make sure you have a rag handy to catch all the remnents. If you want to give it a really detailed clean you can pull apart the throttle body, but obviously thats going to take quite a bit longer.

 

[digisol]

The pic I got to see was just a light carbon film on the outside of the t/b, all the baked on crud was on the inside and holding the throttle open allbeit a small amount but the air flow going past the small area between the plate and body was restricted at just off idle throttle openings, why it still went fine with any decent amount of right foot.

The 1.5mm buildup was no exageration all on the inside and out of sight unless the butterfly was opened, I used the Nulon carb and t/b cleaner and an old toothbrush on the stubborn buildup, worked a treat inside and out.

It's not advised to spray it into the IAC control unit hole unless it's been removed, would be a bugger to stuff that on an otherwise simple job and have it idling at 1,500 rpm.

All I know is it's now like another car to drive, might have to keep the thing another 250K, problem is I doubt that I will last that long, the car may well outlive me, such is life.