Guys, I want to bang my head with Wall. Have you ever lost your keys, what do you do, find it everywhere, look at it again and again at same place or nearby. Same is the issue with me ????
[TD] 9[SUP]th[/SUP] generation corolla Xli, 2007 model, 135000 km on clock, with engine 2nz-fe 1nz-fe is neither vvt or vvt-i is a plain engine without O2 sensor but has variable resistor so I have no help from internet except www.toyodiy.com website which gives exact engine details, components attached along with part numbers once you insert frame no of your car on site.
(03/2007 TOYOTA COROLLA (NZE120R-GEMDKP) )
OBD test on this vehicle does not provides information related to Long Term Fuel Trim LTFT and Short term fuel trim STFT cross checked on my OBD device and that?s from Toyata Rawal Motors, Toyata GT motors so how do I determine the air to fuel mixture of this EFI car as they say that computer they have from company does not shows LTFT,STFT on this vehicle.
Car starts well on cold start up on petrol, but stalls if we press accelerator in morning while engine is cold while on petrol. Anyway once switched to CNG then flies but after 5 minutes once temperature has reached its optimum temperature then car runs well even on petrol. [/I]
PROBLEM TAG: [/I]
[I]Vehicle stumbles on cold startup if accelerated but no problem while idling. [/I]
PROBLEM TAG: [/I]
[I]Car stalls on petrol once accelerated from cold startup but becomes ok once attained proper operating temperature.[/I]
Problem is a year old problem, guess what I have tried and done numbers of times
Fuel Pump: Changed with denso original
Fuel Filter: Changed twice with Toyata genuine fuel filter twice in last 15000km.
Fuel Pressure Regulator: changed twice in last 15000 km.
Fuel Pressure Test: Nobody had fuel gauge so had to buy my own. Fuel pressure is 42PSI once clicked and does not drops below 36psi even after 5 minutes. Mechanic says that let is try to install kabli and let?s see and I am sick and tired of everyone guessing, spending my money and still no results.
Injectors ultrasonic cleaning: done from Nazir autos some 7000km back, injectors were fine but were cleaned again. Since then I regulator disconnect the injectors and keep on cleaning with carburetor cleaner at times and again expecting a magic to take place. I have disconnected individual injectors several time once car is idling and it stalls indicating that fuel injectors are firing properly.
Ignition Coils: although, car runs perfectly well on CNG but ignition coils were disconnected while car was idling. It stalled and showed all of them to be ok both on petrol and CNG.
Spark Plugs: sick and tired of changing them, adjusting the clearance and cleaning it after every 500km. this has became a joke.
Tappet settings and valve clearance: Checked before twice and again checked today. Verified to be ok and within specs.
Trouble Codes: car does not gives any trouble code.
Throttle body wash: throttle body cleaned, idle control valve adjusted and it seems to work fine as once its position is changed then either idle rpm increase or decreases. Throttle position sensor works ok as obd test reveals that it is changing its position once we hit accelerator.
MAF sensor: it gives flow of air and also provides intake air temperature. I have bought a second hand from scrap yard, switched its position but data on both the sensors matches 100%. Toyata motors have also tried to install a new one as a smart mechanic highlighted a problem with his blind fate, changed it but problem was intact so he took it back declaring the original to be ok.
Intake Manifold: recently, I started suspecting that intake manifold maybe blocked but once it was removed then it seemed clear, slightly dirty but nothing such that can block the air passage. Cleaned and was installed back but problem is intact.
Coolant Temperature Sensor: suspecting that it may be a problem so I looked at its reading on EML327 once car is started. It starts from 20 C and goes all the way to 92 C and now that I look at it every time once car starts. Although, I can change this but will I keep on spending money as results looks ok.
Intake Temperature Sensor: this reading varies from 55 F to 70 F depending upon the temperature and sensor comes within the MAF sensor. It has been replaced with other MAF sensor I have but OBD shows same consistent readings on both the sensors so have attached it back.
Air Filter and Housing blockage: it has no blockage like people do it on CNG cars. Clear air passage, no obstructing in between. Seems fine to me , as I take it off and put it back every time. Clean it as well.
PCV valve: You know this is for Engine ventilation, removed and cleaned, seems ok as air passes one way and installed back. No improvement.
Knock Sensor: Today, I got it opened, although did not had any trouble code from ECU. It seemed perfectly clean from inside so got it installed again without disturbing anything.
Variable Resistor: this controls the air to fuel mixture, increases supply of petrol and has a specific procedure for increasing or decreasing the petrol. But you know what, I visited toyata GT motors, Toyata motors as they did not had the specific equipment to test and adjust it. So blindly said that problem is not with this part. Manual says that it not be disturbed or adjusted without measuring the CO2 content from exhaust.
Fuel Tank inspection: fuel tank opened, checked and seems ok and crystal clear.
Engine Condition: throws water droplets out on cold startup in morning from exhaust, mechanic says that its a sign that engine is in good condition, oil changes after every 5k, diary maintained, no signs of sludge so far. rocks on cng.
I don?t know, I have got nut, Every mechanic wants to repeat older steps, once satisfied that they are ok, then says ?I don?t know?. Even toyata mechanic says ? temporarily tries to satisfy me, charges and next day problem is back. Don?t have so much time that I keep running around a shitty reason, they keep charging me and problems remains intact.
Kindly help me solve the puzzle as I keep on repeating previous steps. If problem is known, I can repair it but here I don?t know what is an issue.