Leanburn 1.8 Problem

[Sjoerd]

Hello,

About 2 months ago i bought a Toyota Carina E Wagon 1.8 16V. I experienced the sam problem as Cassnapper;" Experiencing problem that seem to be linked to Econmy mode whereby reaction to pressing accelerator is delayed and at times sluggish. Particualrly when shifting from 3rd to 4th gear.

Also finding that the engine 'misses?' when I am crusing in 5th. "

I went 5 times to the dealer, They changed different parts with no effect. Went the sixt time : Problem solved for 95%

The feul consumption is a little more. It was 1L:15km it now is about 1L:13.7km. But the performence is alot better. It drove like my Grandfather had driven it for Several years. But now it almost as good as the Corolla 1.6 16V from 1990. A little slower but in 5th faster. I thought it a good try.

Greets

Sjoerd from Holland

[JNR]

hi m8 what was it they changed the 6th time as i have a toyota carina 18 i cdx with leanburn engine and have similiar problems can u tell me wat they done the 6th time thank you

[The Real Tao]

Please tell us how they sorted your problem Sjoerd.

Couldnt they just disconnect the "lean-burn" bit of its brain as this low fuel to air ratio mode makes for an unresponsive drive.

It would be even handier if they could rig a switch in the cabin so it could be switched off when required.That way we could salvage some of the cars excellent fuel economy.

p.s mines an avensis but same engine as yours. :P

[Sjoerd]

:D

The problem is the same as when the car had lpg. The mecanic has the leanburn adjusted. There are different settings of the valve. At first he tried to close it but that's no good. The best resuld was to open the valve fully.

He told me it's like an open air filter. When there is a "normal" engine you have 1 air inlet per cylinder.

the leanburn engine has 2 one without valve and one with valve. The problem is that the engine between about 2300 rpm and 3500 rpm uses the leanburn mode. The problem is the engine and throttle are sensitive. when you open the valve fully the airflow is max like a normal engine. Like cars on lpg that was a problem. So they changed the setting. I personelly had little hope but they supprised me. It was indeed very powerfull and the economy was also good. It's for me a top solution because the car runs smoothly. The dealer told me there was no negative effect for the engine on long terms.

Greets Sjoerd

Hope it's your solution as well.

[JNR]

thank you m8 i will be contacting my dealer with this suggestion :P hope it works lol l8r dude peace out B)

[sjrainsford]

Just had a quick look at my car, and I think I know what you mean, at the end of the inlet ports there is a vacuum valve which presumably operates butterflies within the inlets. It would be worth knowing exactly what it does, because there is no way that this is all there is to the lean-burn system. Also it has a screw adjustment setting too.

Any thoughts? It's about time those people at haynes bought out a manual for the avensis!

[cal]

This thing is called SCV (Swirl Control Valve). It meant to create swirl inside the cylinder so that it burns evenly even when the mixture is lean.

In simple terms, in ordinary situation, the car runs on lean burn and the SCV is shut to create swirl. Once the engine reaches certain rpm (usually around 4000 rpm+), i.e. when putting the foot down, the SCV opens and at this point, the engine swithes the lean burn mode off and functions as conventional engine.

To do this, it has 2 intake ports to each cylinders and one of the ports have been partially blocked by a flap, a bit like 8 valve engine instead of 16 valve when running on lean burn and this flap opens when under load.

The SCV is controlled by VSV (Vacuum Switching Valve). When the vacuum is present, the SCV is shut. When it switches the lean burn off, the VSV cuts the vacuum so the SCV opens. Now, you can manually open the SCV by disconnecting the hose leading to the SCV diaphram. This is what Sjoerd was saying. When running on LPG, it does not functions as lean burn anymore, thus SCV becomes meaningless thus best to leave the SCV fully opened.

You are right that there is more to it than this about the lean burn system. This is just one of the intake issues. :)

[Sjoerd]

Thank's for explaining Cal. My englisch is not as good as it should be. The technical term mostly i don't know.

But I think you wrote it down exactly as the dealer told me.

Thanx

Greets Sjoerd

[sjrainsford]

Thought it was sommat like that, thanks! Actually i'm not bothered about a haynes manual too much, just a manual on that engine would be interesting. Even though, it's not the most technical of engines!

Cheers

[Andy40]

Hi Stuart

You dont need to buy a Haynes manual for the Avensis, just buy the one for the Carina E as it shares all the same engines 1.6 through to 2.0 and a lot of the interior, exterior fittings are the same also.

I have a 2.0 Carina E but my Haynes manual goes into great depth regarding the 1.8 lean burn engine and you should find all you need to know in that manual as your engine is more or less entirely unchanged from the Carina 1.8.

Maybe that's why they haven't introduced one for the Avensis pre the VVTi engines.

Hope this helps

[sjrainsford]

Ok, thanks for that then Andy40. Will probably get a Haynes manual on that note then, after all - most routine servicing is on the engine etc rather than body and fittings. The only reason I have liked the manuals in the past is they normally give a good description of the engine in them.

Cheers!

[Sjoerd]

Hello

I have ask what they exactly did.

They disconnected the vacum of the valves.

On top of the main intake port are two vacumtubes.

When you diconect the one to the valves en close it at the intake port, the valve is than fully opend, it's simple. :hokus-pokus: Don't close the tube because the valve is than SHUT. :(

As i watched my engine it was the right tube.

Good luck

Sjoerd :D