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Have a 2002 corolla , 1.8 engine. Auto. Approximately 140, 000 miles / 240,000 km. It completely boogs down on acceleration. Will not shift to 2nd. Appears no issues with fuel. Fuel test is 50psi. NO CODES (Mil light is working) MAF is working, Air filter new. Fuel rail and injectors good.
Compression good. Exhaust flowing , no blockage. Starts great and idles at spec.
Again NO codes, Could the Throttle body position sensor or the Variable Timing Module cause this ???? Again NO CODES . I’m at a loss, need help. Thanks, Eric …. in Cape Breton / Canada
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At idle it is 750 to 810. Fairly normal idle at operating temp. I’m just checking the throttle position sensor. Appears ok I have also tested for vacuum leaks , I just can’t find any. It has not dropped a code.
My fuel pressure is approx. 50 to 48 psi. For this model I read 45 to 55 ok. However it does drop to about 46/47 psi. when accelerate at idle and driving . With the exhaust in place ; I routed the fuel gage to outside of windshield and drove the car with same results, no acceleration, watched the fuel pressure, It dropped but not below 45 psi. I then removed the to entire exhaust and found no restrictions what so ever. Then drove the car with no exhaust and basically same results.
I’m suspicious of the fuel pump , even though it is showing ok and I,m aware the fuel regulator is in the pump assembly.
As for your question; I do not know what a long and short term fuel trims are ; at idle, nor do I know how to test for this. Thanks, EricYes, the throttle position sensor can be the problem. Unplug the connector and meassure the resistance while very slowly pushing the gas pedal from 0-100%. It should be a even smooth change in resistance, no jumping around.
You can also do the same thing with voltage at the pins where the tps connects to the ECU. Backprobe it and the voltage should change smoothly as you press the pedal with the ignition on.
Fuel trims you need a scanner to check. A cheap bluetooth one will work fine.
It can also be the MAF sensor, how did you verify it is working?
I have access to another 2002 corolla which has no issues, swapped out the MAF sensor with same results. A friend has an Actron Elite reader with live data capability, going to check MAF with his scanner, I’m not sure if it can view fuel trim. However thanks for the advice will be doing those checks. sincere thanks …. Eric
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