940 & 960 B234F carbon clean - backyard style

While changing the spark plugs I took the chance to peak at the pistons tops and they looked pretty cruddy. Oily, crusty black carbon crap that looked like coal.

Engine has been running rough, noisy and very thirsty. V8 thirsty. I’m ok with V8 fuel consumption if I’m getting V8 power but I wasn’t.

- purchased a spray can of cleaner from Repco (Japanese, can’t remember name sorry but it’s about $17)
- Got a 750mL jam jar of hot water with a heated table spoon of soda bicarb in it.

~ drove car home, got it nice and hot.
~ pulled all the spark plugs, they were 8 weeks old and already black and sooty.
~ sprayed a good amount and the cleaner I bought into each chamber, about 5-7 seconds per cylinder.
~ put the plugs back in and went for a snooze for half an hour.
~ came back, started the motor and took great delight in seeing the clouds of blue smoke that came out the exhaust. It smelt like the smoke from a steam train. Took about 15 seconds for the engine to run smoothly.

~ pulled the vacuum line off the back of the fuel pressure regulator and while holding revs up around 3000rpm (turning throttle spindle by hand) I used the vacuum hose like straw and gave the engine repeated little sips of about half a second with a gap between sips of about 1-2 seconds.
~ the engine stumbles a little while doing this but you just turn throttle a bit to keep the revs up.

- I probably put 100mL into it over a few minutes.

~ pulled the plugs, pistons looking better, a little grey. Cylinders 1&2 were better than 3&4 as the water is coming in at the front of the intake mini fold.

~ stayed more of the Japanese jizz in the cylinders. Plugs in, left it for about 5-10 minutes and started it up again. Less smoke. I took this as a positive sign.

~ pulled the small vac hose off the crank case breather and used this one as a straw this time.

~ put another 100mL or so through the engine.

~ I followed the instructions on the Japanese spray can and sprayed it up the little crankcase breather pipe while holding revs up. This I take it, helps clean the crud off the intake calves too.

Now the fun part: took the car for a nice little drive, holding it in second and surging up the revs up hills etc and guess what???

Not only was the engine running more smoothly, it sounded better AND I found my missing horses:-)

The engine runs better now but still not perfect.

Plugs are now greyish, not black and sooty, and pistons tops definitely look better.

It still drops revs too low when coming to a stop whilst in drive, then sits at too low an idle while in gear and stationary.

Don’t know if fuel pumps are working properly or fuel filters need replacing.

Plugs and leads are new.

Will have to check injectors for spray pattern etc.
Don’t know if fuel filters are needing replacement or if fuel pumps are running properly.


> You follow this at your own risk <

- everything I’ve done here is from reading other forums.

- if you add too much water you run the risk of hydraulic lock up and bending important bits of the engine.

- operating the throttle spindle has your hand/arm close tho engine belts and there’s a risk you’ll get hurt.


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