Rx450h Shuddering

rayaans · September 20, 2015

Just been having an issue with the 450h sometimes. Its not exactly reproducible but -

the car basically shudders at a standstill when its warming up. I can feel the vibration in the driver's seat and its an odd feeling. It only seems to happen sometimes.

The only way I can describe it is like a light shivering which is felt through the car.

Any ideas?

is200 Newbie · September 20, 2015

Carbon build up - I have experienced this although my car is an IS and not an RX

When I first had it I spent a lot of time looking into the cause - it was reported as a big problem in the states where they use a lower ron value of fuel than Europe .. it was put down to a buildup of carbon due to lower ron fuels being used. An upper rebuild of the engines affected cured this.

How I have resolved mine was to use an additive - a lot of people report these to be a placebo effect - I used it along with changing to the higher ron fuels, filling up on alternate fills.

It has worked for me - I used BG44 and Shell V Power.

rayaans · September 20, 2015

Carbon build up - I have experienced this although my car is an IS and not an RX

When I first had it I spent a lot of time looking into the cause - it was reported as a big problem in the states where they use a lower ron value of fuel than Europe .. it was put down to a buildup of carbon due to lower ron fuels being used. An upper rebuild of the engines affected cured this.

How I have resolved mine was to use an additive - a lot of people report these to be a placebo effect - I used it along with changing to the higher ron fuels, filling up on alternate fills.

It has worked for me - I used BG44 and Shell V Power.

Wow really? I've been using BP regular which I would have thought is more than adequate.

I'll give the additive and BP ultimate a try to see what happens

is200 Newbie · September 20, 2015

Its not a quick fix - you will notice over a 3 month period or so, a reduction in the instances where it shivers. Then after that just make a judgement on when you add the BP Ultimate and maybe get into the habit of adding a can of additive every year.

Might be worth you recording the times it happens just for re-assurance that what you are doing is actually helping to decrease the times it shivers. You will probably still experience it during the use of the additive and other fuel grade but give the additive and fuel a chance to work. When I done mine I used 3 tins over as many months but it did work for me. Also I did not dose the fuel up as directed (one can per full tank) I used a can per half tank and made sure I was not doing any long runs just so it could stay in the system longer.

As for the higher ron fuel, this will have additives already manufactured into it.

From a fill up with your BP ultimate (just make sure its 98 ron) you will definitely notice a difference after around 50 miles if filled up from empty. Difference will be in engine response. If you are not sure, try it in manual mode where its felt more.

rayaans · September 21, 2015

Its not a quick fix - you will notice over a 3 month period or so, a reduction in the instances where it shivers. Then after that just make a judgement on when you add the BP Ultimate and maybe get into the habit of adding a can of additive every year.

Might be worth you recording the times it happens just for re-assurance that what you are doing is actually helping to decrease the times it shivers. You will probably still experience it during the use of the additive and other fuel grade but give the additive and fuel a chance to work. When I done mine I used 3 tins over as many months but it did work for me. Also I did not dose the fuel up as directed (one can per full tank) I used a can per half tank and made sure I was not doing any long runs just so it could stay in the system longer.

As for the higher ron fuel, this will have additives already manufactured into it.

From a fill up with your BP ultimate (just make sure its 98 ron) you will definitely notice a difference after around 50 miles if filled up from empty. Difference will be in engine response. If you are not sure, try it in manual mode where its felt more.

Im not too sure what RON BP Ultimate is - I think its 95 but it still has the additives in it. May try Tesco Momentum 99 or Shell V Power to see if it cleans it up a bit.

Never had this on my 8 year old RX300 so don't know why its happening on the 450h. Maybe its because the engine doesn't get used as much.

ChrisKaye · September 23, 2015

I've (touch wood) never had this problem but always run on Shell v-power or Tesco momentum (when I've saved up fuel save points which Tescos recently have stopped). Usually a mix of 3 x v-power, 1 x Momentum a month mix. We do this with all our cars.

Yes, you pay more per litre BUT I swear I get at least 30miles more from a tank with high octane which off-sets the higher costs.

Other things worth checking are that air filter is in good shape and MAF sensor is clean. Check coil pack connector clips are clean from corrosion and have some grease on them to keep moisture out.

ColinBarber · September 23, 2015

You shouldn't have to use 97+ RON fuel in the RX450h, 95 RON is fine.

Whilst it is possible I wouldn't have thought carbon build-up would be that great on a 2012 model, especially a hybrid where the engine would have done a lot less revolutions compared to a standard petrol engine with the same mileage.

The IS250 suffers from carbon build-up on the intake valves because it is direct injection, no fuel washes the valves. This isn't the case with the RX450h which uses a conventional injection system so build-up is less likely.

rayaans · September 23, 2015

I have used the BP Ultimate a few times, only issue is availability. Lots of BP stations do BP Ultimate diesel but not petrol! Argh.

I have a feeling it may be stale fuel :/ usually I drop my son off to uni 90 miles altogether on weekends along with daily commuting so end up using a full tank in 2 weeks. He's starting again tomorrow so more fuel will be used from now on.

I've had the current fuel in there for 4 weeks and it's still showing 60 miles!

Parrot of Doom · September 24, 2015

I'd be more inclined to clean the throttle body, and to check all the obvious rubber pipes for any cracks/splits.

PCM · September 27, 2015

I'd be more inclined to clean the throttle body, and to check all the obvious rubber pipes for any cracks/splits.

Maybe do both... have a clean up and try Shell V-Power or similar for a few weeks?

rayaans · September 27, 2015

Its disappeared now - hasn't shuddered in ages!

DanD · September 28, 2015

Well... it has been a lot warmer these past few days! :-)

billgatesisaconman · September 29, 2015

Well... it has been a lot warmer these past few days! :-)

It hasn't in Yorkshire though .... lol

rayaans · September 30, 2015

Been OK here, pretty sunny and 16 degrees on average which I think is pretty good for this time of year

billgatesisaconman · October 1, 2015

Comparitively speaking, 250 miles in a southerly direction may just add a couple of degree's ?... ;-)

DanD · October 2, 2015

Oh at least.

Don't listen to what they say on TV/radio... it's 25 degrees down here in Hampshire this afternoon...

Dr. Amdahl · October 3, 2015

Mine shudders very slightly when the air con cuts in, are you sure it's not just that?

ChrisKaye · October 3, 2015

Hi Keith, if you have an RX350, your A/C pump is mechanical, so when it kicks in whilst you are stationary, you'd feel/see your revs drop a little before the car computer kicks the idle speed up to compensate for the extra load from A/C...

The RX450h Rayaans has uses an electric pump for the A/C I believe, but I wouldn't know how that would affect things when it kicks in having zero experience owning/driving a hybrid!

Can the A/C on the rx450h be used when the engine is off (say waiting at traffic lights, for example)?

rayaans · October 3, 2015

Hi Keith, if you have an RX350, your A/C pump is mechanical, so when it kicks in whilst you are stationary, you'd feel/see your revs drop a little before the car computer kicks the idle speed up to compensate for the extra load from A/C...

The RX450h Rayaans has uses an electric pump for the A/C I believe, but I wouldn't know how that would affect things when it kicks in having zero experience owning/driving a hybrid!

Can the A/C on the rx450h be used when the engine is off (say waiting at traffic lights, for example)?

Yep, AC can be used all the time when ON

billgatesisaconman · October 4, 2015

Hi Keith, if you have an RX350, your A/C pump is mechanical, so when it kicks in whilst you are stationary, you'd feel/see your revs drop a little before the car computer kicks the idle speed up to compensate for the extra load from A/C...

The RX450h Rayaans has uses an electric pump for the A/C I believe, but I wouldn't know how that would affect things when it kicks in having zero experience owning/driving a hybrid!

Can the A/C on the rx450h be used when the engine is off (say waiting at traffic lights, for example)?

When a/c kicks in it usually fires the engine up (depending on temp) it has a power gauge instead of a rev counter ... engine revs are down to power usage ... you need to drive one of these Rx hybrids Chris ... ;-)