Air flow meter reading

[Davide 0]

Hello everyone!

I’ve recently bought a 205 1.9 gti from 1991, with the Motronic ignition.

 

First thing: when I start it I always wait some time to allow the gas pump doing its work properly. If I do this only once, the car will start but cuts off right away. If i turn on and off two/three times the instrument panel and let the gas pump work, it will start properly. So might this really be a sign of an almost-end-of-its-career gas pump?

 

now the other question, more complicated:

Once the engine is started, it will idle nicely for some minutes. After those, it will start idle roughly. Last times i drove it, the engine was cutting off as well whenever I was about to stop, so when rpms were going down, but this only happened in the first 2/3 minutes of driving. It happened as well, the very last time I drove it, that it cut off while driving down from a mountain road (it didn’t happen when going up) and when I was pressing the throttle it had a slow response (it was accelerating for like the first second, and then it was accelerating). 
now I haven’t been driving it for a month (I’m waiting for the new license plate…) and I was trying to find out what it could be. I found a video online of a guy having apparently my same problem, and he took a look at the air flow meter cables. He tried to measure the voltage of the four cables reaching it and has some tables with the values, but my cables are in different positions.

I tried measuring the voltage as well, and now I will attach values I got and picture of the cables.

By the way, is there anybody who has got some precise values I can refer to? And could it be a problem of a wrong reading by sensors therefore it thinks that there is more air then what there actually is, resulting in a wrong air/gasoline blend?

How is it fixable? Directly changing all the Bosch part?

 

Thanks in advance for your response.

Davide

 

 

cable voltage, from pin 1 to 4 (reading it from my thumb to my index in the picture)

pin 1:  1.47 V when idling, at around 3000 rpms it reached 2.2

pin 2: 4.9 V, both idling and with higher rpms

pin 3: Earth, 0V

pin 4: 2.7 v idling, but voltage was getting lower when rpms where getting higher, reaching 2.2 v at around 3000 rpm