Corolla RPM Drop + Missing + Non-Smooth Acceleration

[qasimmalik]

We have Gli 1.3 2011 ODO 85,000 kms, CNG installed. problem is the car drops rpm, does missing, and momentarily gives proper power other wise it feels like it is out of fuel. on CNG it is miserable even engine stop when u forget to pump the pedal on idling, but the surprising part is, if we remove the battery wires for 2-3 hours or leave it over night and reconnect the terminals, all signs of trouble are gone but it returns to same situation in a day or two

Mechanic say it is fine mechanically and problems lies in some electronics, sensors or ECU. Can anybody else experienced this problem ?
any solution ?
may be the air intake is damaged hmm ?

[qasimmalik]

Koi to reply krdo bhaii need urgent help

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[dms664]

Koi to reply krdo bhaii need urgent help

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Change ur advancer/emulator

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[qasimmalik]

Change ur advancer/emulator

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Brother the problem exists ob petrol aswell , do u think adv+emu are still responsible ?

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[saadz137]

Brother the problem exists ob petrol aswell , do u think adv+emu are still responsible ?

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Get the injection test done of the fuel injectors of your car from any Toyota Dealer Ship. They have this special kind of instrument to verify the consumbtion from each injector.

I had the similar problem in my corolla 2010, it felt like missing on petrol and CNG both, the average went really low and car dint seem to accelerate. Through the above test it was figured out that one of the injector was notw orking properly in the combusition test. I just got the Tappet adjusted from my mechanic. and its fine since then Alhamdullillah.

btw this problem is v common in Corolla 2009+ models.

[drtanveerali]

Problem is your fuel filter as the CNG installed vehicles do have stored petrol unused for many months this lead to DAMAR like substance built in fuel tank when that bad by product come in fuel line dueto faulty fuel filter it chokes the whole system.

[Xulfiqar]

Get the injection test done of the fuel injectors of your car from any Toyota Dealer Ship. They have this special kind of instrument to verify the consumbtion from each injector.

I had the similar problem in my corolla 2010, it felt like missing on petrol and CNG both, the average went really low and car dint seem to accelerate. Through the above test it was figured out that one of the injector was notw orking properly in the combusition test. I just got the Tappet adjusted from my mechanic. and its fine since then Alhamdullillah.

btw this problem is v common in Corolla 2009+ models.

that test is still done with a grease pencil on piston type aircraft engines, I use a infrared thermometer, any cylinder that is colder than the others by about 100F or more is not getting fuel (verify that you have good compression first)

[qasimmalik]

Problem is your fuel filter as the CNG installed vehicles do have stored petrol unused for many months this lead to DAMAR like substance built in fuel tank when that bad by product come in fuel line dueto faulty fuel filter it chokes the whole system.

Brother if the culprit is fuel filter, then vehicle should perform normal on cng but it performs slightly bettr on petrol

And the second thing that rmoving battery terminals for 2, 3 hours or over night resolves the issue temporarily but it kicks in aftr an hour or so, why is it so xulfiqar sahb ap hi kuch irshad ferma dain

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[5555]

There could be a problem with intake manifold as its inner side break down due to cng

[5555]

Is there any sound from intake manifold?????

[uetian805]

Plz get service its throttle body frm some toyota dealership.

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[qaiser45]

Change plugs, plugs coil, clean throttle body and put new air filter and enjoy the ride. If problem exist in CNG then check you advancer is working properly. Keep smiling

[garrisonian14]

@qasimmalik, Sir was your problem resolved? Although this thread is very old. I am facing same problem with my gli 1.3 2012 model running on petrol, CNG not installed,. I went to Toyota, they serviced throttle body, done tuning, plugs changed. But problem still there.

Any advice?

[cpanday678]

Same was the problem with my gli 2012. Toyota guys changed fuel pump, fuel filter, and throttle body cleaning but problem was still there. Then a friend suggested to get the tappets checked. So i got my cars tappets checked by a local mechanic and Alhamdulliah car runs fine now...

[abdkhan2]

Im also facing the same but its on petrol only runs fine on cng, its all happened after replacing the throttle body

[omer480]

We have Gli 1.3 2011 ODO 85,000 kms, CNG installed. problem is the car drops rpm, does missing, and momentarily gives proper power other wise it feels like it is out of fuel. on CNG it is miserable even engine stop when u forget to pump the pedal on idling, but the surprising part is, if we remove the battery wires for 2-3 hours or leave it over night and reconnect the terminals, all signs of trouble are gone but it returns to same situation in a day or two

Mechanic say it is fine mechanically and problems lies in some electronics, sensors or ECU. Can anybody else experienced this problem ?
any solution ?
may be the air intake is damaged hmm ?

Check the O2 and MAF sensors, might solve the problem.

[rockstar.mij]

@qasimmalik, Sir was your problem resolved? Although this thread is very old. I am facing same problem with my gli 1.3 2012 model running on petrol, CNG not installed,. I went to Toyota, they serviced throttle body, done tuning, plugs changed. But problem still there.

Any advice?

Clean your fuel injectors. I have got the same problem week ago but sort out now.

[textile_expert]

We have Gli 1.3 2011 ODO 85,000 kms, CNG installed. problem is the car drops rpm, does missing, and momentarily gives proper power other wise it feels like it is out of fuel. on CNG it is miserable even engine stop when u forget to pump the pedal on idling, but the surprising part is, if we remove the battery wires for 2-3 hours or leave it over night and reconnect the terminals, all signs of trouble are gone but it returns to same situation in a day or two

Mechanic say it is fine mechanically and problems lies in some electronics, sensors or ECU. Can anybody else experienced this problem ?
any solution ?
may be the air intake is damaged hmm ?

similar problem i am facing with my 1.3 gli. the problem started with rough idling which disappears on cleaning the fuel injection system like throttle body, plugs, etc. the problem again re-occur in a couple of months time. some times, the gas treatment liquids also help in controlling the problem, like Gumout, STP's fuel injection system cleaners, but the problem can only be minimized for some time but can not be eliminated permanently. initially, when this problem started to appear, the symptoms were mild and resetting the ECU by disconnecting the battery terminals helped restoring the smooth idling. i have consulted many mechanics, toyota service centers, but it has been impossible to diagnose the exact root cause of the problem. the computer scanner does not show any error or faulty readings. in order to carry out a perfect diagnosis, i started replacing fuel injection parts one by one so that i might catch the real culprit in the system. i changed the throttle body, the problem vanished for few days and re-appeared. i changed the plugs, same thing happened, rough idling disappeared for some time and re-appeared. i changed the coils on plugs, the problem vanished for some time and re-appeared. i changed the fuel injectors, the problem still persists. i have also tried to fuel my car with high octane on full time basis but that does not help fixing the problem too. i changed the manifold too.

historical background of my car: initially, an italian landirenzo cng kit was installed in the car which i uninstalled at around 60,000 km. i am doubtful if this problem even existed in the time of cng as well because i used to witness slow throttle response. i tolerated the problem as the symptoms were very mild and thus negligible but the problem was identifiable. after uninstalling the cng kit, with the passage of time, the symptoms became worst and made driving the car impossible. the rough idling becomes worst, the car does not accelerate easily, the rpm drops and turns the engine off.

please advise solutions with technical logic and reasoning. your valuable advice is highly appreciated.

best regards...

[hamz80]

[quote="textile_expert, post:18, topic:205003, full:true"]

We have Gli 1.3 2011 ODO 85,000 kms, CNG installed. problem is the car drops rpm, does missing, and momentarily gives proper power other wise it feels like it is out of fuel. on CNG it is miserable even engine stop when u forget to pump the pedal on idling, but the surprising part is, if we remove the battery wires for 2-3 hours or leave it over night and reconnect the terminals, all signs of trouble are gone but it returns to same situation in a day or two

Mechanic say it is fine mechanically and problems lies in some electronics, sensors or ECU. Can anybody else experienced this problem ?
any solution ?
may be the air intake is damaged hmm ?

similar problem i am facing with my 1.3 gli. the problem started with rough idling which disappears on cleaning the fuel injection system like throttle body, plugs, etc. the problem again re-occur in a couple of months time. some times, the gas treatment liquids also help in controlling the problem, like Gumout, STP's fuel injection system cleaners, but the problem can only be minimized for some time but can not be eliminated permanently. initially, when this problem started to appear, the symptoms were mild and resetting the ECU by disconnecting the battery terminals helped restoring the smooth idling. i have consulted many mechanics, toyota service centers, but it has been impossible to diagnose the exact root cause of the problem. the computer scanner does not show any error or faulty readings. in order to carry out a perfect diagnosis, i started replacing fuel injection parts one by one so that i might catch the real culprit in the system. i changed the throttle body, the problem vanished for few days and re-appeared. i changed the plugs, same thing happened, rough idling disappeared for some time and re-appeared. i changed the coils on plugs, the problem vanished for some time and re-appeared. i changed the fuel injectors, the problem still persists. i have also tried to fuel my car with high octane on full time basis but that does not help fixing the problem too. i changed the manifold too.

historical background of my car: initially, an italian landirenzo cng kit was installed in the car which i uninstalled at around 60,000 km. i am doubtful if this problem even existed in the time of cng as well because i used to witness slow throttle response. i tolerated the problem as the symptoms were very mild and thus negligible but the problem was identifiable. after uninstalling the cng kit, with the passage of time, the symptoms became worst and made driving the car impossible. the rough idling becomes worst, the car does not accelerate easily, the rpm drops and turns the engine off.

please advise solutions with technical logic and reasoning. your valuable advice is highly appreciated.

best regards...

[/quote]

Hi everyone,

Just a suggestion from my side based on experience.
All the vehicles discussed above have had CNG. The problem is that when you uninstall the CNG kit, complete wiring is not brought back to original. There are multiple connections still left out which cause such behaviour. Please ensure that entire wiring of CNG is removed and the original wires are joined. I have seen a two inch wire inducted in the original wiring on one of my car that had CNG removed. The car used to accelerate like a turtle with missing and bad idling. Culprit was that small piece of wire and removing that brought life back to the car.

[textile_expert]

We have Gli 1.3 2011 ODO 85,000 kms, CNG installed. problem is the car drops rpm, does missing, and momentarily gives proper power other wise it feels like it is out of fuel. on CNG it is miserable even engine stop when u forget to pump the pedal on idling, but the surprising part is, if we remove the battery wires for 2-3 hours or leave it over night and reconnect the terminals, all signs of trouble are gone but it returns to same situation in a day or two

Mechanic say it is fine mechanically and problems lies in some electronics, sensors or ECU. Can anybody else experienced this problem ?
any solution ?
may be the air intake is damaged hmm ?

similar problem i am facing with my 1.3 gli. the problem started with rough idling which disappears on cleaning the fuel injection system like throttle body, plugs, etc. the problem again re-occur in a couple of months time. some times, the gas treatment liquids also help in controlling the problem, like Gumout, STP's fuel injection system cleaners, but the problem can only be minimized for some time but can not be eliminated permanently. initially, when this problem started to appear, the symptoms were mild and resetting the ECU by disconnecting the battery terminals helped restoring the smooth idling. i have consulted many mechanics, toyota service centers, but it has been impossible to diagnose the exact root cause of the problem. the computer scanner does not show any error or faulty readings. in order to carry out a perfect diagnosis, i started replacing fuel injection parts one by one so that i might catch the real culprit in the system. i changed the throttle body, the problem vanished for few days and re-appeared. i changed the plugs, same thing happened, rough idling disappeared for some time and re-appeared. i changed the coils on plugs, the problem vanished for some time and re-appeared. i changed the fuel injectors, the problem still persists. i have also tried to fuel my car with high octane on full time basis but that does not help fixing the problem too. i changed the manifold too.

historical background of my car: initially, an italian landirenzo cng kit was installed in the car which i uninstalled at around 60,000 km. i am doubtful if this problem even existed in the time of cng as well because i used to witness slow throttle response. i tolerated the problem as the symptoms were very mild and thus negligible but the problem was identifiable. after uninstalling the cng kit, with the passage of time, the symptoms became worst and made driving the car impossible. the rough idling becomes worst, the car does not accelerate easily, the rpm drops and turns the engine off.

please advise solutions with technical logic and reasoning. your valuable advice is highly appreciated.

best regards...

Hi everyone,

Just a suggestion from my side based on experience.
All the vehicles discussed above have had CNG. The problem is that when you uninstall the CNG kit, complete wiring is not brought back to original. There are multiple connections still left out which cause such behaviour. Please ensure that entire wiring of CNG is removed and the original wires are joined. I have seen a two inch wire inducted in the original wiring on one of my car that had CNG removed. The car used to accelerate like a turtle with missing and bad idling. Culprit was that small piece of wire and removing that brought life back to the car.

Great advice... this is possible... Thanks a lot brother...

I will check it...

Best regards...