Throttle Response On Gs450h

[braindead]

I've noticed a few times that if I try and accelerate hard from a standing start or at very low speed, there seems to be a noticeable time lag between hitting the pedal and the car taking off. It seems like an age but in reality is probably a second.

It's caught me out a couple of times when I thought I could safely nip out at a junction and the darned thing has a delayed reaction.

I drive it in standard (not power) mode most of the time and the throttle response at speed is just fine. It's not traction control as the orange light doesn't flicker.

Anyone else noticed this or do I just expect too much?

Malc

[aido]

Probably not the sort of thing you want to hear but someone modified the accellerator pedal in their IS300 to make it more responsive - can't remember the exact details but will try and find it if you like to give you an idea?

[aido]

This is the one I was looking for:

http://www.lexusownersclub.co.uk/forum/ind...c=24634&hl=

[braindead]

Probably not the sort of thing you want to hear but someone modified the accellerator pedal in their IS300 to make it more responsive - can't remember the exact details but will try and find it if you like to give you an idea?

Interesting. Are all the GS models fitted with fly by wire throttles?

I have to say, I wouldn't want to modify it. It's an annoyance more than anything.

[braindead]

Probably not the sort of thing you want to hear but someone modified the accellerator pedal in their IS300 to make it more responsive - can't remember the exact details but will try and find it if you like to give you an idea?

Interesting. Are all the GS models fitted with fly by wire throttles?

I have to say, I wouldn't want to modify it. It's an annoyance more than anything.

I just read the thread thanks. It's not major surgery so I'll go take a look at mine in the daylight tomorrow. Seems like the spring is effectively a damper.

Thanks for the tip - I will report back

[aido]

Yeah that's exactly right, might have to have a nosey at mine as well as I'd forgotten all about this until I saw your post and my car should have a similar setup I think?

[aido]

If that doesn't sort it there maybe an aftermarket TOMS bit of kit that may help with it - there's this one but it doesn't list the 450:

http://www.l-tunedparts.com/product/?id=2925

[Parthiban]

Sorry if this is a dumb question, but in these instances, is it when the engine is off and then it has to switch on?

[aido]

Sorry if this is a dumb question, but in these instances, is it when the engine is off and then it has to switch on?

Good point mate - not sure how these work?

[Parthiban]

Sorry if this is a dumb question, but in these instances, is it when the engine is off and then it has to switch on?

Good point mate - not sure how these work?

Obviously our Prius has nowhere near as much power as the GS450h, but there is definitely a very slight lag from the time taken for the engine to fire up when it's off. In the Prius it's not incredibly noticeable as the electric motors cover the gap - but in something as big and heavy as the GS, perhaps the power difference is too great?

So if the lag you're talking about is when you're sitting at a roundabout waiting to pull out, I'd assume that it's because the engine has switched off, and will take a second to fire up when you boot it

[dave1]

I had a testdrive in a GS450h a few weeks ago and I was really impressed by the ride and the responsiveness of the engine. There was certainly no noticeable lag in the one I drove, in fact I was amazed at the low down power/acceleration. On a par with my 430 and possibly slightly quicker off the mark!

[braindead]

Sorry if this is a dumb question, but in these instances, is it when the engine is off and then it has to switch on?

Good point mate - not sure how these work?

Obviously our Prius has nowhere near as much power as the GS450h, but there is definitely a very slight lag from the time taken for the engine to fire up when it's off. In the Prius it's not incredibly noticeable as the electric motors cover the gap - but in something as big and heavy as the GS, perhaps the power difference is too great?

So if the lag you're talking about is when you're sitting at a roundabout waiting to pull out, I'd assume that it's because the engine has switched off, and will take a second to fire up when you boot it

My previous car was a Prius :) and I'm something of an anorak about hybrids. I'm 90% sure it's not an engine starting issue.

Given that an electric motor has max torque at zero revs then it doesn't really matter that the engine is not on. The electric motor gets you moving very quickly.

I've just been trying it again and the response at say 20 or 30 mph is much keener in fact it goes like stink. However from very low speed or stopped you get this slight lag then it flies off like a bullet.

[braindead]

I've just been into the local Lexus dealer and let the service manager test drive it. He agrees there is a lag. Typically you lift off then re-apply the throttle and you get it.

He says it shouldn't be like that so it's booked in for a look on Thursday. He did ask that I check with the dealer who did the 40k service that the gearbox oil had been changed.

Will update late next week.

Malc

[aido]

Nice one mate, hopefully they'll get it sorted then :)

[braindead]

It gets better. I asked the dealer who did the 40k service if the gearbox oil had been changed and he stated that a 40k service only demands an oil check and top-up.

He also stated that there was a Lexus Tech Bulletin recommending a reprogramming of the ECU which may have some bearing on the issue. We'll see

[aido]

Interesting stuff - definitely sounds like you're getting somewhere with that one though mate :)

Is it Derby who are sorting it then?

[Parthiban]

Sounds promising, usually once the dealer's on your side it's pretty easy to get a speedy conclusion.

Let us know what the problem was when you find out :)

[Huddy]

Malc. The GS450h should accelerate from standstill almost instantly, much faster than a standard petrol car. The only time mine hasn't done this is when I accidently let the hybrid batteries drain, and it was then very slow to pick up. I could be worth taking it into your dealer to have it checked out.

[braindead]

Interesting stuff - definitely sounds like you're getting somewhere with that one though mate :)

Is it Derby who are sorting it then?

It is Derby who are taking a look though I got it used from Listers in Coventry. Interesting that they both have different theories though the manager at Listers talked to a technician whereas the Derby manager didn't.

The attitude of both dealers seems very good. When I asked about cost the chap in Derby stated that warranty should cover it on the basis that it shouldn't be behaving in this manner.

We'll see :)

[aido]

That's awesome :)

I need to pop down there one day next week, probably Friday if I can blag the insurers that I can drive again, if not it'll be the week after as have some bits waiting for me :D

[braindead]

Malc. The GS450h should accelerate from standstill almost instantly, much faster than a standard petrol car. The only time mine hasn't done this is when I accidently let the hybrid batteries drain, and it was then very slow to pick up. I could be worth taking it into your dealer to have it checked out.

Huddy - it does. It's just that there is a delay between hitting the throttle and the thing deciding it's going. When it goes it flies as you would expect. The Derby Manager said it resembled the turbo lag you got on older turbo cars. That kind of sums it up really.

[Huddy]

Sorry, I didn't write my previous post very well. I meant to say that the time taken from standstill to say 5mph, should be virtually instant. I imagine this is because the initial acceleration is provided by the electric motor, which is very torquey. Of course, the petrol engine will cut in a few milliseconds after that, but the electric motor should be able to provide good acceleration during the second or so that you say you feel it lagging. I don't think mine behaves as you describe, so why not ask Lexus if you can drive a demo car, so you can judge if yours has a problem?

[braindead]

Sorry, I didn't write my previous post very well. I meant to say that the time taken from standstill to say 5mph, should be virtually instant. I imagine this is because the initial acceleration is provided by the electric motor, which is very torquey. Of course, the petrol engine will cut in a few milliseconds after that, but the electric motor should be able to provide good acceleration during the second or so that you say you feel it lagging. I don't think mine behaves as you describe, so why not ask Lexus if you can drive a demo car, so you can judge if yours has a problem?

The service manager at Derby has already driven it and said it's not right. Booked in next week. I think I mentioned it in my earlier posts.

[Huddy]

Sorry I missed that. I'm sure they'll sort it out for you. I almost bought my car from the Derby dealer. Nice people to deal with.

[kns]

Whilst I am generaly a pretty slow driver- usually trying to get best economy, last time I used the car I had to pull away quickly from some traffic lights (to get across to another lane), and the acceleration with instant and as you would expect very strong.

However on another point I do notice from time to time a slight jerk a second a so after I've stopped, and I am wondering whether its a characteristic of the petrol engine shutting down. Does anyone else notice this at all?

Keith.