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2005 Toyota Prado negitive 40 long term fuel trims
Hi All
I have a 2005 120 series Toyota Landcruiser Prado with a 1grfe motor in the shop at the moment. it has -40 LTFT on both banks at idle. have checked all the normal suspects IE: TPS, MAF, fuel pressure and vacume. Driveableity issues are if you try to take off like a normal person IE; 1/4 -3/4 throttle it will bog really bad for 2-3 seconds till the STFT reaches +20 and then it will take off. The O2 sensors are switching correctly and have even removed and done a smother test to verify. When we remmoved the 02 sensors there was no sign of for over fueling. just for refrance i have put the values at idel below.
Smother test is where with the vehicle running and O2 sensors at operating temp you remove them from the exhaust and while watching live data you get a rag with a hydrocarbon on it ie petrol or shallite and smothe th O2 and watch it switch from + to- to confirm that it is not biving a false signal
You can do this easier by pulling a vacuum line and seeing positive numbers and by introducing propane in the intake and seeing negative numbers.
true however when the LTFT is -40 the ecu is pulling so much fuel that even when you disconect the brake booster line it still will not go + ---- hence the smother test.
Problem solved.
First of all thanks to those who look and helped on this problem.
The problem was the injectors.
After exhausting all research i contacted the customer and explained that we had narrowed it down to 2 possibilities 1/ the ECU 2/ the injectors- how ever the 2nd option being unlikley as both banks were the same. it was at this point that the customer told me that they had put a set of injectors in a approx 100km ago
needless to say i wasnt overly impressed as had asked multipule times what/if they had already done to the car.
and yes they were a cheap set of injectors off ebay.
now all i have to do is try and work out the bill..... thanks all.
