If you are not connected to the car, how do you know its not in closed loop?

Depends out temp. I live in cold climate so it can be anything +50-90celcius.

It warms like it should and thermostat opens in 195f and car engine temp is around that in driving when engine is fully warmed.

Fuel pressure is 3bar in idle and driving, and also holds 10minutes when engine is shutted down. I have gauge and ive tested it many different situations. Engine vacuum is also ok when i checked by gauge.

Idle is feeling heavier and fuel consumption is heavier. And you smell exhaust gas is rich.

I think also that 3500-4000rpm rev cut is caused by open loop? I said that range because it varys. It happens on idle and driving. And it has been revved higher when it worked so it should not cut revs that early

With your logic I have to believe he has the exact vehicle you do with the same module and software. Is that correct? No......I'm done here.

There is own file for engine codes and ecm numbers. So you need choose those right. If you choose wrong tunerpro does not give anything.


Yes ln3 and same year car

These are rare here in europe and tech1 is hard to find.


But even withouth scan tool, aldl socket can show open/closed loop in many models? I think same here.

I just nees know all reasons which can cause to not go closed loop so i can check all parts. Manually multimeter tesr is also valid.


Ive readed many topics about poor aftermarket mafs in these vehicles. I ordered three new and two were bad


But car is not giving any fault codes so fault can be totaled sensor or then ecm is bad. I just wonder can maf do macig tricks.. the original bad maf did not either give fault code but idle was jumping and mot test failed because emissions were high. New maf cured those problems then.

Now i have not tested emissions yet, but in open loop those will fail

Sorry, I made a mistake in my post:

I should have said, if you get these readings, but your O2 data does not show good cross counts when the engine is running, then you either have a bad connection, bad harness, or bad O2 sensor....

The Internet tells me that 3 bar is 43.5113 PSI, seems within spec.

195 degrees is good.

Cathedral, if the car runs at normal operating temp, and that O2 sensor is not changing, then he should do my test immediately, to determine if it is the ECM or the O2 sensor circuit that is the problem....

One thing to remember, do not look at the O2 sensor readings while idling.....many vehicles in the past have failed emissions because, they drove their vehicle to the inspection station, and then either turned their vehicle off or just let it idle while waiting for the inspection....many times, especially if an old O2 sensor was in the vehicle(they become "lazy" as they age), that sensor would not get hot enough to start to work....that'* why with OBD II they added the heater element to the sensor to get it working almost instantly...

so observe the O2 data....if it is not switching and staying at .455, bring your idle up to 2000 rpms for 30-60 seconds, and see if the O2 sensor now starts to change....

I must do your test in asap...

Ive tried many new o2 sensors and one which i tried on this engine is now my 4.3 chevy and working fine. So o2 sensor wasnt bad because it works on other car.

And o2 changes very good when car is closed loop, that happens 1-3 times to 20-30 starts/drivings. But like yesterday, all good but restarting engine = open loop for rest of day

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Agree. I was just translating from bar to PSI for everyone'* benefit and to rule that out.

I agree he needs to do your test next.