Rx300 2000 - Power Bottoming Out At 85Mph

[Sexylexy300]

Hi

I have a 2000 rx300 which bottoms out on power at 85mph.

Up until then and through the transmission everything is fine.

Thoughts?

S

[ColinBarber]

what rpm is the engine doing at that speed?

[Sexylexy300]

Hi, thank you for replying but I can honestly say I didn't notice. I don't like driving fast so was too busy looking at the road. However, all I would say is that it went smashing up to that, loads of power through the gears and then just went flat as if the revs dropped from the sound of the engine. Since then I have checked under the bonnnet and have noticed a pipe that appears to be in half near to the accelerator pully. If you put your finger over the upper end whilst the engine is running its as if it has suction. I think it stems from near the inlet part of the exhaust on the upper part and the bottom half disappears down past the radiator towards the air conditioning. It runs along the side of the air filter and is next to another pipe. It doesnt appear split just separated as if it should join the other bit with some sort of connection.

I know if will be impossible for you to perhaps know what I mean but you never know if you are an expert!

S

[ColinBarber]

Does it look like the pipe going up to the air box by the two arrows in the top left of this picture?

There are a number of vacuum hoses connected to the throttle body, not all are visible with the air filter/air box in the way. It is important that these don't become disconnected otherwise the engine will run poorly.

Is the engine running differently since you noticed this issue? I wonder if the pipe came off when you were at speed, or maybe it is been like it for a while and you haven't noticed.

[Graham Gardner]

The national speed limit is 70mph was this on private land?

[wackyjim]

You could spend hours trying to find whats causing the problem ,probably best to find a friendly garage and ask them to run a fault test for you or if you are techy minded buy a cheap fault finder online. http://www.ebay.co.uk/itm/like/320907639556?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

[ColinBarber]

or if you are techy minded buy a cheap fault finder online. http://www.ebay.co.uk/itm/like/320907639556?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

that is assuming a fault is being generated. Probably won't be for a simple vacuum leak.

[wackyjim]

or if you are techy minded buy a cheap fault finder online. http://www.ebay.co.uk/itm/like/320907639556?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

that is assuming a fault is being generated. Probably won't be for a simple vacuum leak.

True...but worth a try

[Sexylexy300]

Colin, on the picture I can see a pipe attached to an inlet on the top part of the air filter. This is attached fine on my car but the culprit pipe runs parallel to this, is the same size but is separated about 6inches down. It is definetly a vacuum pipe of some kind due to the suction when you put your finger on it.

S

[Sexylexy300]

Graham

It was on my dads aerodrome actually!!!

S

[ColinBarber]

Any chance of some pictures? If it isn't the line going to the air box then it would either go to the throttle body itself or the vacuum valves on top of the intake manifold under the sliver engine cover.

Next step would be to remove the air box and engine cover to investigate further.

[Sexylexy300]

Hi

Hopefully the pictures upload and give you a clue.

S

[ColinBarber]

I believe there should just be a plastic coupler which joins those two hoses together. The hose on the left is the main feed from the throttle body and goes down to a vacuum surge tank which then feeds to the other hoses coming back up.

The hose which goes down under the engine cover is the feed from the surge tank to the Vacuum Switching Valves (VSV). One of those controls the ACIS valve which changes the air intake path within the inlet manifold at certain engine revs. This won't be able to operate if it doesn't have a vacuum feed so I suspect your lack of power coincided with the ACIS trying to operate.

The part code of the coupler is 90412-05005 which you can see in the following diagram:

http://eu.toyotaspares(blocked word)/images_eu_a2/172567B.gif

The part should only be around £5.

Until fixed you should plug up the left pipe, the one with the vacuum, otherwise the engine is pulling in air which isn't being metered and will therefore probably run lean, especially on idle.

[Sexylexy300]

Hi, thank you so much for this I really appreciate it. I will endeavour to buy the part. Do I take it, Will I need to get that from a main dealer.

It means a lot to keep this car on the road because I love it, but being 14 yrs old that might take a bit of doing but if I can I sure will.

Thanks again

S

[ColinBarber]

I don't think there is anything special about the coupler but if you get the genuine part then you know it is the right size. Any Toyota or Lexus dealer should be able to get the part for you.

If you aren't near a dealer you can order from Lexus Swindon online and get it shipped:

http://www.lexuspartsdirect.co.uk/Lexus-spareparts-enquiry.html