Sluggish Acceleration And Unusual Slowdown

asrock · January 16, 2015

My car is a 2007 Allion 260 A15, it has a very sluggish acceleration, I have to step on the accelerator hard to get it going, when I release the accelerator it slows down rapidly. This started happening after I changed the plugs to NGK iridium and I did a tune-up also. It wasn’t noticeable first but after 2-3 months, started happening frequently and I think its getting worse. It’s really annoying when driving long distance, putting the gear to S allows a good acceleration though.

Also it has a slight vibration when idle, with or without ac. RPM is at about 750. I have replaced 2 engine mounts which were worn-out a bit, but the problem is still there.

Fuel consumption is somewhat ok, with some hard acceleration it did 15.5kmpl on colombo-kandy route. I know allions are heavy and has a sluggish acceleration, but when I bought this car it had a reasonably good acceleration.

kush · January 16, 2015

Where did you do the tune up, better take it to the agents and do a thorough scan, could be a sensor issue.

When did you last change transmission fluid.

A friend of mine had a similar issue and agents just cleared some sensor error s and it was ok, apparently ECU was getting wrong signals, they told him to come back if the issue persists to replace the sensor which he didn’t have to.

Cost was Rs 1,600/- or so

Crosswind · January 16, 2015

My car is a 2007 Allion 260 A15, it has a very sluggish acceleration, I have to step on the accelerator hard to get it going, when I release the accelerator it slows down rapidly. This started happening after I changed the plugs to NGK iridium and I did a tune-up also. It wasn’t noticeable first but after 2-3 months, started happening frequently and I think its getting worse. It’s really annoying when driving long distance, putting the gear to S allows a good acceleration though.
Also it has a slight vibration when idle, with or without ac. RPM is at about 750. I have replaced 2 engine mounts which were worn-out a bit, but the problem is still there.

Fuel consumption is somewhat ok, with some hard acceleration it did 15.5kmpl on colombo-kandy route. I know allions are heavy and has a sluggish acceleration, but when I bought this car it had a reasonably good acceleration.

As this happened immediately after changing the plugs, my first suspect would be a faulty plug or a loose or damaged plug wire. Could you rule those out first?

Davy · January 16, 2015

I'm with Crosswind on this. Get the plugs and the ignition system checked out. Rapid slow down and rough idle does sound like a cylinder not working properly.

If the ignition system is fine, a diagnostic scan would give enough information to determine the cause.

MV-5 · January 16, 2015

switch it back to copper

asrock · January 16, 2015

Thanks Crosswind and Davy, I will get the ignition system checked out first. Will the agent be too costly for this? I don’t think my usual maka bass will be able to diagnose this properly, he is the one who did the plug change and the tune-up.

@kush: When I bought this car the owner said he changed the CVT fluid at 45,000km, now its about 61,000km. I’m going to change the CVT fluid on my next service which is due in another 1000kms. Can the CVT cause such a problem? Gear change is smooth from D to N to R, no lag.

The Don · January 16, 2015

First and foremost did you confirm that these are the correct plugs?

Usually ignition failure (coil pack or wire) results in a check engine light so I wonder if they are to blame. If it is ignition related, what is likely is the plug is partially working or is the wrong plug so the engine is not producing as much power as before.

Also it sounds like the gears are not changing as well as it should, because sudden deccalaration can also be a result of engine breaking by being on a higher gear. CVT transmissions don't have specific gear ratios, but the gears do move infinitely between ranges, so there might be an issue in that. I don't know enough about CVT transmissions to advise exactly what components might be affected, or if a CVT fluid change may resolve the prpblem.

CNX · January 16, 2015

Confirm whether correct plugs were used. Denso iridium tipped ones are the original equipment. ECU has to be reset to clear error codes after plug replacement and throttle body cleaning.

Crosswind · January 16, 2015

Usually ignition failure (coil pack or wire) results in a check engine light so I wonder if they are to blame. If it is ignition related, what is likely is the plug is partially working or is the wrong plug so the engine is not producing as much power as before.

Although that should happen theoretically, my experience tells me it's not always the case. Once I was running a Mondeo for several weeks on just 3 cylinders. Same happened with a Cefiro (5 cylinders in that case), with no check light.

Schiffer · January 16, 2015

check the code number of the spark plugs with toyota lanka. i dont know about the allion but for my corona premio they recomended not to use NGK and to use either toyota iridium plugs or Denso Iridium plugs, They gave the code numbers for them as well

asrock · January 18, 2015

Thanks guys for your valuable advice. I will go to Toyota Lanka next week to get the plugs and ignition system checked. If there are any other recommended places please let me know. I sure hope it’s something with the plugs instead of the CVT.

The Don · January 19, 2015

Although that should happen theoretically, my experience tells me it's not always the case. Once I was running a Mondeo for several weeks on just 3 cylinders. Same happened with a Cefiro (5 cylinders in that case), with no check light.

Interesting. I had the same problem in my old Mirage and the check engine light came on as soon as the third cylinder started misfiring due to a broken wire. I assume in my case the wire ran into the electronic ignition mechenism from the ECU, but I'm very supprised if the misfire does not even get recorded even if it does not trigger the check engine light.......

The Don · January 19, 2015

Thanks guys for your valuable advice. I will go to Toyota Lanka next week to get the plugs and ignition system checked. If there are any other recommended places please let me know. I sure hope it’s something with the plugs instead of the CVT.

I think if its a issue with the electronic ignition system or a sensor, the diagnostic equipment at the agent would be the best to get a diagnosis report of. They should be able to tell you if there is a fault with the gearbox as well. If that is not conclusive, you will have to rely on a skilled mechanic.

anuNTZ · March 20, 2018

I have the same problem in my allion 260 did you solve the problem

asrock · March 20, 2018

No, it was still there when I sold the car more than 2 years back. In the end I got used to it, recently I drove a friend 2009 Allion A15 and I felt the same symptoms.

Twin Turbo · March 21, 2018

When was the transmission service last done? ,....

hrm · March 21, 2018

12 hours ago, asrock said:

No, it was still there when I sold the car more than 2 years back. In the end I got used to it, recently I drove a friend 2009 Allion A15 and I felt the same symptoms.

I guess the weight of the car, 1.5 engine combined with CVT transmission could be the case. 1.8 suits better for Allion. Did you felt that slowdown in every speed? Usually CVT slows/applies engine brake if car travel less than 40KMPH and above there's no such. At least that's how I feel in my Vitz.

Edited March 21, 2018 by hrm

anuNTZ · March 21, 2018

It’s only below 40kmh not in high speeds I did a manual Ecu reset yesterday now the sluggish acceleration is no more there the car responds good but the pausing symptom is there

anuNTZ · March 21, 2018

Did it about 1000kms back because if this

asrock · March 21, 2018

7 hours ago, Twin Turbo said:

When was the transmission service last done? ,....

I did a CVT oil change at 62 or 63k kms before I sold the car. The mechanic said the old oil wasn't bad.

2 hours ago, hrm said:

I guess the weight of the car, 1.5 engine combined with CVT transmission could be the case. 1.8 suits better for Allion. Did you felt that slowdown in every speed? Usually CVT slows/applies engine brake if car travel less than 40KMPH and above there's no such. At least that's how I feel in my Vitz.

No only at low speeds, I also think it could be common to all A15s. But the thing is it had some what good acceleration when I first bought it.

anuNTZ · March 21, 2018

3 hours ago, asrock said:

I did a CVT oil change at 62 or 63k kms before I sold the car. The mechanic said the old oil wasn't bad.

No only at low speeds, I also think it could be common to all A15s. But the thing is it had some what good acceleration when I first bought it.

Mine the acceleration is good after ecu reset but it has something to do with the spark plugs or ignition and I doubt the fuel pump also anyways I’m gonna check it today will give a feedback after that and I’m going to do a system scan as well

anuNTZ · March 22, 2018

Today I went to the agents and they did perform a Cctv oil pressure caliberation as per what they said and the back pull is a common thing due to CVT braking which is absolutely normal