Help: Yaris Lacks Power At Low Revs

[foggy08]

ive owned my 1.0 55 plate t2 yaris for the past 3 years .milage 75k .up untill recently its been fine ( a bit revvy but fine) but in the last week or 2 its developed a fault . if you change into second from first a tad early (especialy on a hill ) it dies untill you hit 2000 - 2500 revs then its got loads of power .ive changed plugs ,air filter ,oil and filter .since its started but no change .put it on a code reader (eBay job) no faults .any suggestions before it goes into the stealer .it also just passed its mot ,so emmitions must be ok. although i did smell sulphyr once ...........ps when it idles it is a bit rattly ( timming chain ) . so any ideas

[foggy08]

also the mpg has went down to about 37mpg from 42....any ideas

update ...booked in to toyota

[foggy08]

oh well western toyota .could not find any fault codes . but recomended a full service at 250.59 and that would help them to probe into the reason for the lack of power. when i pointed to the fact the oil and filters were changed less than a month ago and the plugs were less than a week old ,their reply was .. did you use genuine toyota parts ..as we only recomend genuine parts ....... they did find an oil leak on the rocker cover and timing belt cover ,but at 357.26 i can live with it....and when they were at it,they could change the rattle on the timing chain.at an additional 290.56 . .............so all in all ,i think that was 52 pounds. which could have been better spent.

[Madasafish]

You may have a dirty/damaged air flow meter...Will not show up on diagnostics...

I have no idea how to check though... dirty will be obvious though.

[foggy08]

You may have a dirty/damaged air flow meter...Will not show up on diagnostics...

I have no idea how to check though... dirty will be obvious though.

thanks for the reply . which one is the air flow meter......blue on the right hand side or the black one on the left of the filter cover or is it somewhere else ..thanks

ps why would it not show on diagnostics? is there anything else that would not show?

[Madasafish]

I assume yours is a Mark 1 Yaris?

The airflow meter is mounted to the side of the air cleaner and has a wiring plug going into it.

It looks like this..

http://cgi.ebay.co.uk/yaris-1-0-air-flow-meter-mb197400-3010-222040j010-/220727244683?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item33645e778b

Cleaning? Use carburettor cleaning spray. ONLY.

Other non detectable failures are split hoses on air intake system.. and oiling up/dirt in throttle body...

[foggy08]

I assume yours is a Mark 1 Yaris?

The airflow meter is mounted to the side of the air cleaner and has a wiring plug going into it.

It looks like this..

http://cgi.ebay.co.uk/yaris-1-0-air-flow-meter-mb197400-3010-222040j010-/220727244683?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item33645e778b

Cleaning? Use carburettor cleaning spray. ONLY.

Other non detectable failures are split hoses on air intake system.. and oiling up/dirt in throttle body...

cheers mate ive checked and the hoses ,all ok . so im going for the airflow route . im a member on the transit forum as well and they all recon its a maf problem as well.

[stantheman1]

I assume yours is a Mark 1 Yaris?

The airflow meter is mounted to the side of the air cleaner and has a wiring plug going into it.

It looks like this..

http://cgi.ebay.co.uk/yaris-1-0-air-flow-meter-mb197400-3010-222040j010-/220727244683?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item33645e778b

Cleaning? Use carburettor cleaning spray. ONLY.

Other non detectable failures are split hoses on air intake system.. and oiling up/dirt in throttle body...

cheers mate ive checked and the hoses ,all ok . so im going for the airflow route . im a member on the transit forum as well and they all recon its a maf problem as well.

A couple of helpful tips when cleaning the sensor, first place a rag or paper towel over the alternator air vents, just in case one of the screws fall out whilst removing/replacing the sensor and secondly do not touch the thin sensor wires when spraying the cleaner.

While your at it also check the condition of the accelerator cable where it connects to the throttle body as sometimes they fray and if gone unoticed can break.

Good Luck!

[hawkerpaul]

Are you sure the clutch isnt slipping?

[foggy08]

hi i replaced the mass airflow sensor . its still the same .one thing i noticed was ...if you let the car drive on tick over in 2nd and gently apply the gas its not too bad but if you floor it it just dies and you need to go down to first . ..also it doesnt happen when running cold .with the autochoke on ...............................on the opposite side of the accelerator cable there is a sensor of some kind . ( ie . right hand side of the throttle housing ) does anyone know what this does ?)........

the next thing i need to know is ......where do i go next , auto electrician or auto tuner . any ideas?

[siray123]

Does it idle okay or fluctuate?, has it had the valve clearance checked or fuel filter checked/changed?

[foggy08]

idles fine . but if you set the revs to 2000 and try to hold it there it goes up to 2500-3000........its petrol .so no fuel filter ( to the best of my knowledge ) .and the valves have not been touched ......but no eml displayed.

[stantheman1]

hi i replaced the mass airflow sensor . its still the same .one thing i noticed was ...if you let the car drive on tick over in 2nd and gently apply the gas its not too bad but if you floor it it just dies and you need to go down to first . ..also it doesnt happen when running cold .with the autochoke on ...............................on the opposite side of the accelerator cable there is a sensor of some kind . ( ie . right hand side of the throttle housing ) does anyone know what this does ?)........

the next thing i need to know is ......where do i go next , auto electrician or auto tuner . any ideas?

The sensor of some kind you speak of is the MAF sensor (I don't know what sensor you cleaned/changed thinking it was the MAF sensor)but if you had cleaned or changed the correct sensor then I would have said check the temperature sensor next as you say the car runs ok when cold.

A useul tip when replacing any sensor on the yaris is to make sure you obtain the correct one i.e. French or Jap as they may look similar but wont work in the wrong vehicle, yours is definitely French.

[foggy08]

it was defo the airflow sensor i changed .the same kind, the part numbers were the same 22204-0j010 ....

on an old carb, webber for example when you accelerated it gave an extra little squirt of fuel .....thats what seems to be missing ....im stumped

[siray123]

Sensor you are on about is either a MAF or if it had a rod and attaches to the throttle plate its a TPS sensor (throttle position sensor).

It will have a fuel filter, well more like a sock on the end of the fuel pump, there's a small possibility of it being dirty but i doubt it with a car thats only covered 75k, worth checking though, unless quite dirty it wont effect fuel delivery. I looked at a 120k Honda last year and the filter was only very slightly dirty.

It doubt your car is drive by wire, so check the tightness of the throttle cable, however be aware that they should be 'taught' NOT super tight.

Valve clearance, you will be able to adjust those.

What is the coolant temp doing/showing or is it just 'HOT/COLD' like my 07 d4d?. Cars with faulty thermostats etc cause the engine to take ages to warm up and thus run rich initially.

Either way i strongly a ODB2 reader for either a laptop or a mobile phone (see my post above), this way you can monitor any of the sensor in voltage and coolant etc and many more sensors/values - this could help you and prove invaluable they really are useful and is worth it for the cost or an OBD2 reader (£10-£28 depending on cable or bluetooth).

CHeers

[Yaris200116]

Hi Foggy08 i have a 2003 yaris. I have the exact problem you discribed. Just would like to know if you could tell me if you found the problem. Thanks. I hope u still visit this site 

[erik010]

hey guys, was there finally a solution to this, since i am having that problem now? thank you very much in advance. this car is getting on my nerves. 2001 yaris.

[FROSTYBALLS]

It is almost a 9 year old topic, and the OP hasn't posted since January 2012, so doubt whether a response will be forthcoming. 

[Madasafish]

EGR valve may be blocked

or dirty MAF sensor

or dirty air filter

or plugs failing/wrong gaps

or failing ignition coil(s)

If no fault codes the above apply.

If any warning lights, read fault codes.

[erik010]

thanks so far guys. most of the above items have all been checked and are ok, i am not getting fault codes. but a couple of more things to go after. this gives me some inspiration to continue. thanks !!