vw afn pasat ,,head scratching fuel issue help

going along and loss of power occurs suddenly ,,,its not in limp mode and is staying that way for a few days now ,,,tried vcds lite no faults ,,swopped maf no difference ,,disconnected maf no difference ,,, checked fuel return from pump which is good ,,,,its boosting well upto 20 psi ,,,,i have a vac guage on fuel ,line and its a good reading ,,,this is twin tanked with veg oil ,,,runs just the same on veg or diesel ,,disconected battery for an hour no difference ,,disconected engine temp sensor no difference,,,, swopped n75 valve no difference ,,swopped inline sensor on intake tube no difference ,,,turbo seems to be working well ,,need someone technical on this one ,,,i have a spare pump ,,but can i just swop it or do i need to code it to car its an r reg passat ,,,was thinking of swopping fuel compensator but sureely if that was duff it would bring up a fault code ,,,no cel at anytime ,,,tia

I wanted to state for the record that I'm pretty sure your run-on sentence with all 57 commas gave me cancer.

No codes stored?

Stop throwing parts at the car - it's obviously not working.

Check your mechanical timing, check your injection timing.

How are your group 13 injector balance #'s? What is your fuel IQ at idle?

Did you install the veggie kit?

Have you done a compression test on the engine?

Exhaust blocked by chunks of carbon ?

mmn

well ihave spare n75 valves ,and its now throwing up fault code of n75 intermittant or short to ground ,which is odd as i have tried 3 n75 valves and its saying the same very unlikely they are all duff .
so could this be wiring .
does anyone know for sure if i can just swop pumps if needed without any coding to specific car .tia

ill get back to u with readings i only have vcds lite though

which blocks do u want me to meaasure ,and how do i post them on here tia

well just measured injection quantity on live run i can barely rev it to 3000 rpm ....i am told it should be Injection quantity should be 3-5 at idle and up to 36-38 at full throttle.
i can get 4 at idle but at full throtle about 23 ,,,i have read It could be an internal injection pump failure, bad ECU, bad QA, sticking fuel shut off solenoid, or bad fuel injectors/nozzles.
swopped fuel shut off valve no difference ..
now can someone tell me
can i just swop an ecu from another afn passat or do i have to code it to car
can i just swop a pump do i have to code it to car
tia

Pump you can just swap - no coding needed - can't tell you about the ECU in your car - no AFN's sold over this side of the Atlantic.

Given your car was run on Veggie, and that pumps are cheap, I would be looking swapping in a known good pump to start.

1491 17.2 2.22 72
1995 21.6 2.48 72
2436 21.8 2.54 72
1344 25 2.42 72
1659 25 2.52 72
1869 25 2.6 72
2100 24.6 2.52 72 these figs are from block 1 left to right rpm ,,mgstr ,volts temp
cannot get mgstr to increse above 25 ,,,that was foot hard down do u know the voltage range .

herre is another from block 15
1512 25 5.07 29
1659 25 5.46 33.6
1827 25 6.24 34.2
1890 25 6.63 36
left to right rpm mgstr fuel consumption and regested mgstr
so can i take it the ecu is sending out the right signal voltage as i see the voltage going up but not mgstr

herre is another from block 04
left to right rpm.. ign requested... ign actual... duty cycle which seem to match well but according to another post the duty cycle should be less than 10 per cent and that post says i should advance timing further
861 1.3 1.5 49.8
861 1.3 1.3 52.2
861 1.3 1.5 51.4
861 1.3 1.3 52.2
861 1.3 1.5 51.4
861 1.3 1.3 52.2
861 1.3 1.1 53.8
861 1.3 1.3 51.8

its fixed after all of that ,,,all it was was a short to ground on earth cable feeding n75
thanks all

pjbisforme said:

its fixed after all of that ,,,all it was was a short to ground on earth cable feeding n75
thanks all

Click to expand...

Weird, as most N75s get power full time and ECU switches ground...