02-23-2015, 05:12 PM
(This post was last modified: 02-23-2015, 05:55 PM by luigi daniel.)
Jerry, John,
Here is why I post here now as I see I have the same issue with the eng coolant outlet temp seen by ECM , only difference is that it seems to be in closed loop :
My old issue : engine cooling water outlet normal ( 83 degC at idle without rad cap on , measured with wire probe inserted into rad inlet/upper pipe) but my Tech1 shows that the ECM sees 15 degC less.
Thermostat was proven OK ( WAHLER p/n3119.88 with 88 deg C opening temp) and installed corectly with proper ring on 4 mm deep well and bleeding hole facing towards the fwd screw holding the cover in place)
I have checked the ECT and it is also corect - 295 ohm at 85 degC water.
Wiring to ECM both passed OK.
Even changed the ECT for fixed resistors - ECM sees 68 degC with 270 ohm and 64 deg with 330 ohm resistors plugged to connector instead of ECT.
These symptoms are the same when using a spare ECM ( for 95 Tracker 16V A/T ) ; my actual one has been overhauled recently.
The lambda sensor is brand new and Denso.
Here is what my Tech 1 sees, when idling at 800 rpm and closed loop :
eng temp 66 degC
MAF mass air flow 1,7 g/s instead of 3,1 g/s, sensor tested OK and hotwire cleaned up.
Fuel injectors pulse 3,4 ms instead of 1,1-1,6 ms
STFT short term fuel trim oscilating 126-130 which is ok.
LTFT long term fuel trim 134 so the engine is running lean.
So, it is obvious that the ECM is trying to compensate by adding extra fuel , like when on warming up phase, when below 70 degC ...
The ISC won't show 50% duty with DLC pins 2 and 4 shorted ; only shows 0% also when in Calibration mode with Tech1, whatever position of idle air adj screw. The ISC, when disconnected, engine almost stalls. ISC has been opened up, was free and clean , it closes when blowing through without power supply, but I havent't checked if rattling when shaken ... It opens when connected to 12V but, I recqon I cannot hear it vibrating neither in normal use neither when test supplyed with 12V.
I cannot find any vacuum leaks. The O2 ( lambda) sensor is brand new ( Denso made)
I use Vetronix Reprogrammable High Capacity Cartridge p/n 02003137 but same readings I've had when using another cartridge ( GM/FORD/CHRYSLER POWERTRAIN)
Anyway, it iddles right and smooth, I only want to improve the fuel consumption as it has increased within the years even with the engine fully overhauled.
I was told about an incorrect definition being released for the 16V ECU and I am probably chasing a non-existent fault and, reading back through the symptoms, its definitely the Tech1 that is wrong. So I've just purchased an used Mastertech from US so as to can use my existing Tech1 cartridges and adaptors. Hope I will receive it soon and I will redo the tests.
Here is why I post here now as I see I have the same issue with the eng coolant outlet temp seen by ECM , only difference is that it seems to be in closed loop :
My old issue : engine cooling water outlet normal ( 83 degC at idle without rad cap on , measured with wire probe inserted into rad inlet/upper pipe) but my Tech1 shows that the ECM sees 15 degC less.
Thermostat was proven OK ( WAHLER p/n3119.88 with 88 deg C opening temp) and installed corectly with proper ring on 4 mm deep well and bleeding hole facing towards the fwd screw holding the cover in place)
I have checked the ECT and it is also corect - 295 ohm at 85 degC water.
Wiring to ECM both passed OK.
Even changed the ECT for fixed resistors - ECM sees 68 degC with 270 ohm and 64 deg with 330 ohm resistors plugged to connector instead of ECT.
These symptoms are the same when using a spare ECM ( for 95 Tracker 16V A/T ) ; my actual one has been overhauled recently.
The lambda sensor is brand new and Denso.
Here is what my Tech 1 sees, when idling at 800 rpm and closed loop :
eng temp 66 degC
MAF mass air flow 1,7 g/s instead of 3,1 g/s, sensor tested OK and hotwire cleaned up.
Fuel injectors pulse 3,4 ms instead of 1,1-1,6 ms
STFT short term fuel trim oscilating 126-130 which is ok.
LTFT long term fuel trim 134 so the engine is running lean.
So, it is obvious that the ECM is trying to compensate by adding extra fuel , like when on warming up phase, when below 70 degC ...
The ISC won't show 50% duty with DLC pins 2 and 4 shorted ; only shows 0% also when in Calibration mode with Tech1, whatever position of idle air adj screw. The ISC, when disconnected, engine almost stalls. ISC has been opened up, was free and clean , it closes when blowing through without power supply, but I havent't checked if rattling when shaken ... It opens when connected to 12V but, I recqon I cannot hear it vibrating neither in normal use neither when test supplyed with 12V.
I cannot find any vacuum leaks. The O2 ( lambda) sensor is brand new ( Denso made)
I use Vetronix Reprogrammable High Capacity Cartridge p/n 02003137 but same readings I've had when using another cartridge ( GM/FORD/CHRYSLER POWERTRAIN)
Anyway, it iddles right and smooth, I only want to improve the fuel consumption as it has increased within the years even with the engine fully overhauled.
I was told about an incorrect definition being released for the 16V ECU and I am probably chasing a non-existent fault and, reading back through the symptoms, its definitely the Tech1 that is wrong. So I've just purchased an used Mastertech from US so as to can use my existing Tech1 cartridges and adaptors. Hope I will receive it soon and I will redo the tests.
95 Geo Tracker 2 doors hard top 3speed A/T 16V 1.6l Fed 4x4