Fuse Box Fuse 18 fuel pump - fault code p1020.

ajsellors said:
Hi,

Thanks for posting your readings. I'm not sure what that third pressure value is, I will need to look into that. I don't think there is a sensor on the low pressure side so the ECU won't know what that is. I will check the values on my FSI and compare with yours. I'll probably be able to do that in the next couple of days (rain permitting!).

Interesting regarding knock sensor fault. I think the knock sensor and pressure regulator and sensor wiring goes in the same loom on the back of the engine. Could anything have been damaged there?

regards

Andrew
Click to expand...
hi Andrew, So I've checked the readings on my healthy FSI and its a different story. The pressure readings are near enough the same in both fields. So i guess one value is expected fuel pressure and the other is actual fuel pressure?, meaning the fuel pressure is way too low on the poorly fsi. attached is a screenshot of the healthy fsi fuel pressure readings.

i also note that the 'load' field shows a value all the time on the healthy FSI, but only very occasionally on the poorly FSI, usually it just shows 0%

cheers
 

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nod said:
hi Andrew, So I've checked the readings on my healthy FSI and its a different story. The pressure readings are near enough the same in both fields. So i guess one value is expected fuel pressure and the other is actual fuel pressure?, meaning the fuel pressure is way too low on the poorly fsi. attached is a screenshot of the healthy fsi fuel pressure readings.

i also note that the 'load' field shows a value all the time on the healthy FSI, but only very occasionally on the poorly FSI, usually it just shows 0%

cheers
Click to expand...

Hi,

Ok, if the values are expected and achieved then the high pressure circuit is way too low.
If the pressure is actually low, either the high pressure pump is pretty much doing nothing or the pressure regulator valve is open all the time and is letting the fuel out, preventing the pressure from building up to the desired level.
It could be that the reading is false and the measured pressure is just completely wrong so its a toss up between the pressure valve or the pressure sensor.

Regarding load, its a calculated thing done by the ECU. It depends on a number of things such as RPM, throttle angle, airflow (MAF), pressure and temperature usually.

All of the above and your knock sensor error could be explained by damage to the wiring loom. Alternative your knock sensor and pressure regulator value (or pressure sensor) are both faulty and need replacing.

warm regards

Andrew
 
Ok, so i think i'm finally getting somewhere with this FSI. I'm now pretty sure the issue is electrical. Today i have compared the electrical readings at the connectors to various sensors on my faulty and on my healthy FSI. The readings are the same with ignition on and engine off, but with engine on there are significant differences.
The voltages at the manifold flap control valve are 14.8v and 0.3v on the healthy FSI and 14.8v and 3.7v on the faulty fsi. The same reading of 14,8v and 3,7v is at several locations around the engine on the faulty FSI.

I have found that at the radiator fan there 4 terminals on the healthy fsi the volatages are 3.8v, 14.8v,3,7v and 3.7v, on the faulty fsi the readings are 0v, 14,8v, 3.7v, 0v, both with engine running.

so, there is something amiss. any electrical gurus on here that can point me in the direction of the potential fault, or a decent guide on how to trace the faulty wire? i'm assuming its a short that is only active when the engine is running, as the battery doesn't drain even after sitting for months...

cheers
 
to finish this thread, i've finally fixed the FSI. I checked out the wiring loom more thoroughly after removing the upper and lower manifolds and found no obvious faults. I changed the air conditioning pressure sensor, I replaced the high pressure fuel pump and the Audi A2 00-05 Shut Off Valve 1.6 FSI - Part 036906519B, and the lower intake manifold along with the fuel pressure sensors on the manifold. After all that, thankfully it is running really well, with no fault codes. It was a mission to sort it, and I still don't know for sure which part fixed the fuel pressure problem. hope that helps someone. cheers nod
 
nod said:
to finish this thread, i've finally fixed the FSI. I checked out the wiring loom more thoroughly after removing the upper and lower manifolds and found no obvious faults. I changed the air conditioning pressure sensor, I replaced the high pressure fuel pump and the Audi A2 00-05 Shut Off Valve 1.6 FSI - Part 036906519B, and the lower intake manifold along with the fuel pressure sensors on the manifold. After all that, thankfully it is running really well, with no fault codes. It was a mission to sort it, and I still don't know for sure which part fixed the fuel pressure problem. hope that helps someone. cheers nod
Click to expand...
Hi nod it would be the high pressure fuel pump what fixed the issue as that was what fixed my FSI when it was running rough

My FSI had the same problems as your FSI and then after changing the high pressure fuel pump it resolved all the issues ?
 
I've got a 1.4 Tdi AMF with steering pump and oil level sensor (probable) CANBUS issues resulting in steering power assistance being minimised - there is a reasonably strong suggestion that I need to test the A/C pressure sensor in the vicinity of the A/C expansion valve as it could be a significant contributor to these problems. Could you expand further on your own experience with this sensor and where you got your hint that this could contribute to your problems?
 
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