DhoRK

Poor Acceleration before and after the tune up

12 posts in this topic

Hello Guys,

This is after a long time I'm posting a new topic.Earlier I felt the car (corolla 121)lacks power when accelerating.So recently I did a tune up from To***a L**ka.They did the job correctly,but still after the tune up also I  experience the lack of power.I also changed Transmission oil 3 or 4 weeks prior to the tune up and also serviced the car on the morning of the day the tuneup did.I'm puzzelled.During the tune up they replaced the petrol filter which has not been changed by the previous owner and cleaned the injectors which has not been cleaned during the last tune up.When they removed the engine cover to replace the valve cover gasket told the engine is in extremely good condition,which has now done 140k kms.After the tune up they said it is not necessary to reset the ecu,since it will automatically adjust.But what I experienced after the tune up was what I experience before.So when I returned home I reset the ecu by disconecting the negative battery wire for about 20mins.After that also no luck.

What I have to experience is a bit strange.When I fully press the accelerator the engine revs but feels a bit slow and also CHANGES THE GEAR ON 4500RPM.But when I drove another car same as mine the car was totally different.On the full pedal it changed the gear just before the redline and also accelerated briskly.So I felt mine has something wrong.But when I accelerate from L the engine revs all the way up till the redline.What is the reason for this??As I had done all the running repairs at the moment I'm a bit embarrased.☹️☹️☹️☹️

Please give your opinions.

Thank You

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Sounds more like a transmission issue than an engine issue. But anyway, was the MAF sensor cleaned as part of the tune up and were the spark plugs cleaned/replaced? If not, then clean the MAF first and then see if the situation improves. Also, was a scan done? Plugging in a scanner and letting the car run will tell you if sensors feeding data into the ECU are sending proper readings. These are things you can do pretty easily, so I suggest looking into them. 

Moving on, was the transmission oil change done by simply draining the old oil and topping up with new oil? If yes, then you might want to get the oil pan removed and a proper clean up done of the pan and filter changed. 

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4 hours ago, Davy said:

Sounds more like a transmission issue than an engine issue. But anyway, was the MAF sensor cleaned as part of the tune up and were the spark plugs cleaned/replaced? If not, then clean the MAF first and then see if the situation improves. Also, was a scan done? Plugging in a scanner and letting the car run will tell you if sensors feeding data into the ECU are sending proper readings. These are things you can do pretty easily, so I suggest looking into them. 

Moving on, was the transmission oil change done by simply draining the old oil and topping up with new oil? If yes, then you might want to get the oil pan removed and a proper clean up done of the pan and filter changed. 

In addition to what Davy suggests, I have had a similar experience in my Honda recently where acceleration felt unbelievably sluggish. I had to get the IACV cleaned for carbon deposits as they told me the most likely cause is poor quality of fuel, and therefore I changed the petrol station. I am yet to replace the in-tank fuel filter, but so far it seems to be back to normal as happily changing gears at normal revs. hope this helps

 

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12 hours ago, Davy said:

Sounds more like a transmission issue than an engine issue. But anyway, was the MAF sensor cleaned as part of the tune up and were the spark plugs cleaned/replaced? If not, then clean the MAF first and then see if the situation improves. Also, was a scan done? Plugging in a scanner and letting the car run will tell you if sensors feeding data into the ECU are sending proper readings. These are things you can do pretty easily, so I suggest looking into them. 

Moving on, was the transmission oil change done by simply draining the old oil and topping up with new oil? If yes, then you might want to get the oil pan removed and a proper clean up done of the pan and filter changed. 

MAF Sensor was cleaned.Plugs changed.Also the transmission oil was changed by removing the oil pan.But during the tuneup they didn't scan the car.They told me that the ecu automatically adjusts according to the values sent by the sensors.

Edited by DhoRK

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Did you tell them of the problem when you handed over the car for tune up? If you did but they did not scan it means they have not done the job properly. BTW did they replace injector washers during tune up? 

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3 hours ago, Rumesh88 said:

Did you tell them of the problem when you handed over the car for tune up? If you did but they did not scan it means they have not done the job properly. BTW did they replace injector washers during tune up? 

Yup.I told them.They replaced the injector washers.

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Another thing, did they remove/clean/replace OCV filter? I'm just trying to eliminate other possibilities that the tune up guys may have over looked.

 

Edited by Rumesh88

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5 hours ago, Rumesh88 said:

Another thing, did they remove/clean/replace OCV filter? I'm just trying to eliminate other possibilities that the tune up guys may have over looked.

 

No.They didn't.If the OCV filter is bad the fuel economy should be affected.But, I'm yet to experience a bad fuel economy after the 96k kms tune up.Before that it burnt gasoline worth of Rs.2000 to travel from Colombo to Kegalle(The day I brought the car home).Also before the tune up this time,it only cost me abt Rs.700 to travel from Kegalle to Waikkala and back to Kegalle which has a total of 140km.

Edited by DhoRK

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Disappointing to hear that the local agent doesn't even do a scan as part of the tune up. Anyway, get a scan done and make sure your EFI system is working as intended. 

@Rumesh88, sorry for my ignorance but how often should the OCV filter usually be replaced? I've no experience owning a car with VVT yet, so not sure. Also, I'm guessing a clogged OCV filter reduces oil pressure to the VVT sprockets which affects performance? 

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27 minutes ago, Davy said:

Disappointing to hear that the local agent doesn't even do a scan as part of the tune up. Anyway, get a scan done and make sure your EFI system is working as intended. 

@Rumesh88, sorry for my ignorance but how often should the OCV filter usually be replaced? I've no experience owning a car with VVT yet, so not sure. Also, I'm guessing a clogged OCV filter reduces oil pressure to the VVT sprockets which affects performance? 

I had VVT set ups in both a 121 - a daily runner for 6 years, and a SCP10 as a second car. Although we call it a filter, it is just is a flimsy metal screen. I used to clean the OCV filters once in a couple of years in both cars but never thought of replacing them. In the manuals I have come across so far it has not been identified as a regular maintenance item. In fact one must be very careful when re-installing the filter to avoid damage to it - something I wouldn't trust in the hands of most local mechs. (The correct procedure is to insert the filter to the Allen key head first and then insert both to the engine block). A partially clogged filter would NOT reduce the STATIC oil pressure but will reduce the flow rate to the VVT vanes thus giving you a slower response to the required change. (If it is totally clogged up it would definitely generate a CEL). Hence it is worthwhile for OP to look into it along with a check on the fuel pressure as well.

Edited by Rumesh88
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6 hours ago, Rumesh88 said:

I had VVT set ups in both a 121 - a daily runner for 6 years, and a SCP10 as a second car. Although we call it a filter, it is just is a flimsy metal screen. I used to clean the OCV filters once in a couple of years in both cars but never thought of replacing them. In the manuals I have come across so far it has not been identified as a regular maintenance item. In fact one must be very careful when re-installing the filter to avoid damage to it - something I wouldn't trust in the hands of most local mechs. (The correct procedure is to insert the filter to the Allen key head first and then insert both to the engine block). A partially clogged filter would NOT reduce the STATIC oil pressure but will reduce the flow rate to the VVT vanes thus giving you a slower response to the required change. (If it is totally clogged up it would definitely generate a CEL). Hence it is worthwhile for OP to look into it along with a check on the fuel pressure as well.

Thanks for that. Makes sense. :)

Edit: I should be shot for saying that I haven't used a vehicle with VVT when the car I have right now has MIVEC which is the same thing. :P

Edited by Davy
oops

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Hey guys,

To my surprise,the problem solved without any repair.Now the car accelerates brutally.Thanks for ur replies.

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