Diagnosing the cause of Yaris power/acceleration issues

[sean18751]

I’ve been given a 2009 Toyota Yaris 1.0 petrol 3Cyl to fix. There’s no codes stored but it seems to be totally gutless, it’s very flat going up the Rev range and needs to be in a low gear with your foot flat on the floor to make any progress. Flat out it just about reaches 75mph.

Usually with these sorts of things there’s a common fault with the engine model that’s easy to diagnose and fix but lots of googling has been inconclusive. I think the engines used in the Aygo, Yaris, IQ, 107 and C1 along with some obscure cars I don’t think were sold in the UK so it’s not exactly uncommon although maybe they’re usually scrapped at this mileage? 97,000.

I think the engine is a 1KR-FE, although the cylinder head has a 1KR-y52 label on it.

So far I’ve:
Confirmed no fault codes
Changed spark plugs (gap exceeded spec on the old ones)
Changed Air filter
Removed the VVTi solenoid to confirm it works under power and the resistance across the contacts is 8ohms which I believe is in spec.
Checked the VVTi filter which was clean

Ideas for things to try next:
Clean MAP sensor (don’t believe there’s a MAF)
Do a compression test
Try and remove intake manifold and clean the EGR ports
Run injector cleaner through the tank

Has anyone experienced something similar or have any ideas on what to try next? I’m clutching at straws with a lot of the above with nothing obvious wrong. The owner wants to spend as little as possible on parts/tools.

[hellorent]

Has it got a fuel filter ?

[sean18751]

The Fuel filter is inside the tank so it’s not serviceable AFAIK.

[Easternlight]

Maybe that's as good as it gets?

Have you driven anything the same/ similar to make you expect more performance?

[E-bmw]

sean18751 said:

The Fuel filter is inside the tank so it’s not serviceable AFAIK.

They are generally still remove/replacable, don't know about the Yaris specifically though.

[sean18751]

Easternlight said:

Maybe that's as good as it gets?

Have you driven anything the same/ similar to make you expect more performance?

So basically someone borrowed the car for 3 years but fast forward to now they no longer need it and they said it won’t do 70mph. The original owner has it back now and agrees the performance is so bad to how he remembered it that there must be something wrong with it.

I dismissed it and put it down to remembering it with rose tinted glasses but upon test driving it it is down quite a bit of power and a lot worse than I’d expect for a car with 70bhp and a top speed of 95mph or so. Usually smaller cars do feel quite nippy until you put the foot down and realise there’s nothing more for them to give but this is particularly bad I wouldn’t even say it’s nippy in 1st gear!

[PositronicRay]

sean18751 said:

Easternlight said:

Maybe that's as good as it gets?

Have you driven anything the same/ similar to make you expect more performance?

So basically someone borrowed the car for 3 years but fast forward to now they no longer need it and they said it won’t do 70mph. The original owner has it back now and agrees the performance is so bad to how he remembered it that there must be something wrong with it.

I dismissed it and put it down to remembering it with rose tinted glasses but upon test driving it it is down quite a bit of power and a lot worse than I’d expect for a car with 70bhp and a top speed of 95mph or so. Usually smaller cars do feel quite nippy until you put the foot down and realise there’s nothing more for them to give but this is particularly bad I wouldn’t even say it’s nippy in 1st gear!

Long shot, blocked catalyst/exhaust?

[sean18751]

Thanks for the advice from everyone.

Just to close out on this….

After doing the major service and cleaning a lot of things which didn’t need cleaning I realised what the problem was upon touching the wheels after a short trip to the shops….

One of the front calipers was seized on, don’t know why I never thought to check it as I’ve had binding rear calipers on other more powerful cars but it’s never made a noticeable difference to acceleration/power on them.

Caliper now replaced and discs/pads changed and it’s a lot better to drive now. The other side with the old caliper is now getting a tad hot, hopefully it’s just bedding in otherwise I’ll replace that one too.

[Dogwatch]

PositronicRay said:

Long shot, blocked catalyst/exhaust?

My thought too. A very frustrating drive in my experience!

[Lazee486]

So I have a 2008 yaris 1.3, and I can say the fuel filter is a non replaceable in tank filter, and really should be replaced after a while, my car was at 200 000km with proper performance issues, Toyota diagnosed it with fuel pump issue and an insane price... Skipping all the drama, a aftermarket complete pump with filter replacement made a huge performance difference... I also had issues with oxygen sensors and still not happy with performance, going through one sensor at a time, but replacing that filter they tell you is for the life of the car really does help.

[E-bmw]

Lazee486 said:

So I have a 2008 yaris 1.3, and I can say the fuel filter is a non replaceable in tank filter, and really should be replaced after a while, my car was at 200 000km with proper performance issues, Toyota diagnosed it with fuel pump issue and an insane price... Skipping all the drama, a aftermarket complete pump with filter replacement made a huge performance difference... I also had issues with oxygen sensors and still not happy with performance, going through one sensor at a time, but replacing that filter they tell you is for the life of the car really does help.

Unfortunately "life of the car" means something different to you & I and the manufacturer.

BMW say the gearbox fluid is "life of the car" which means 100,000 miles.

Mini say the supercharger oil is "not serviceable over the life of the car" (or something similar) but Eaton (manufacturer) say it is 100,000 miles and needs a strip down service.

Sounds like you have found another case of the same.