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

Hi Russell,

thanks for sharing your firstname. I was not aware that it had been your thread before. All I want to hint is that it makes sense to discuss both cars separately.

Actually, since I am the one who posted in response to Russell's post (because it was the same issue be it on another car).

In my mind, it makes sense to group similar problems together, since it is all D jetronic related. But happy to start a new thread if the group feels it is better.

Many thanks
Samuel

Hi Samuel,

if you and Russell are happy with it, then I am happy too. I was just afraid to mix two quite different cars.

It's all good from my perspective. As long as it is helpful. It's not wrong to have it's own thread with a reference to this too.

Not sure there is a "right" or a "wrong" here.

Thanks again for your input!!

Thanks Dr-DJet

Could you tell me how to measure the volume out of the fuel pump?

Also, as I had mentioned before, with the ignition on only (engine not running) I am getting 22 PSI (about 1.6 bar), but 30 PSI (about 2 bar with engine running).

Should the pressure be about 29.5/30 PSI (~ 2 bar) with ignition only on?

Another experiment today... I plugged the intake air temp wire back in... idle if rough and there is hesitation during acceleration. But if I disconnect the the full-load hose from the full-load switch, idle improves, and there is no hesitation upon acceleration, even with the air temp sensor plugged in.

Since both situations lead to enriching the fuel, I think this conforms my car is running too lean. Now onto more through vacuum leak detection and ???

Many thanks for the valuable information

Samuel

Hi Samuel,

your fuel pump 0 580 463 005 must bring at least 355 cm³ in 30 seconds.measured at return line to tank after pressure regulator. After ignition ON your pump will run for 1 to 2 sec. Pressure may drop to 1,6 bar after it stops.

How I would continue on a DS 23 inj:

• Verify that injectors spray properly and same amount
• Measure resistance of injectors from ECU to GND
• Verify that cold start valve does not inject
• Check manifold for vacuum leaks
• Check pressure switch for full-load for leakage and proper operation
• Verify that no one fiddled with MAP sensor potting