Slight mis-fire at partial throttle...until I disconnect air temperature sensor

Hi,

resistance does not change over vacuum. It is always the same. Transformation of input signals from ECU changes. That is why it is also called VLT - variable linear transformer.

Understood that the vacuum has no effect on the sensor. The testing I did was in different temperature water and I saw the resistance change. I matched that with a chart (that I likely found here ) and it seemed within reasonable spec.

The popping when I re-connect seems to be throughout the throttle, not just when slightly opened. It also seems to idle a bit more roughly. All of that goes away when I disconnect the incoming air temperature sensor on the air filter intake.

Hi,

that means you engine runs slightly too lean. Sensor removal increases mixture on warm engine by 10-20% . That is of course not a real solution. You need to find out what is wrong. Exhaust gas measurement per cyl might give a good hint.

I have the same problem with my Citroen DS 23 IE.
Exhaust CO is 2.8% with the air temperature sensor disconnected.

Fuel pressure is 30 PSI with engine running. With ignition only on, the highest fuel pressure is 22 PSI, even after a few on/off ignition cycles. The fuel pump is original to the car (51 years old).

I did turn the knob on the ECU 6 clicks clockwise, but that didn't make a difference.

Could it be a fuel volume issue?

As a follow up question...

Is the only systematic way to enrich the fuel mixture by turning the knob on the CEU clockwise?

Hi,

I do not consider turning rheostat on ECU by 6 clicks a systematic approach. Please remember that it only affects idle-run CO, nothing else.

It is mainly ECU and MAP sensor that really affect mixture. But they need sensors to reply correctly and they need a vacuum tight manifold, working injectors ...