any help be appreciated

[nigelw1982]

my friend got a S8 4.2 V8 on full throttle it back fires and the fault logged is throttle position sensor on looking on elsawin its a cable fly by wire setup with a potentiometer i wonder of theres any audi nuts on here that can help solve this conundrum

[roboblob]

what year is the car ?

[HPsauce]

Originally Posted by nigelw1982

it back fires and the fault logged is throttle position sensor

I don't see any connection there.

What EXACTLY is the fault - full details & text please?
Clear the fault and see if it returns IMMEDIATELY after a misfire event.

And, as requested above, what engine exactly is it and what model year?

[nigelw1982]

its a 1998 4.2 V8 S8 did the fault code reading cleared the codes changed the throttle position sensor the only fault that seems to be returning is this one

17968 - Maximum Engine Speed: Engine Warranty VOID!
P1560 - 35-10 --) - Intermittent

does anyone have any way of knowing exactally what this means there is still a misfire on full load under kick down but the sensor is working fine

[ainarssems]

Check the measuring blocks for misfire, I think it's around 17-19 to see if misfires affect all cylinders equally or some cylinders or one bank more than others to determine if it's general problem or only for some of cylinders.

It is possible that engine have experienced mechanical damage due to over-revving going by error code and that this damage causes misfires.

[nigelw1982]

i have the s8 with me now i will be checking the blocks from 17-20 just checked all the wiring on the oil packs and they all seem to be ok from pin 4a with good continuity to engine earth, checked all the resistances on the coils outer 2 terminals and getting a range from 3.0 ohms to 3.9 ohms will post the actual results along with full compression test info soon

[Bandycoot]

I've just checked the fault code in the Ross-Tech wiki. This is what it cme up with.

17968/P1560/005472 - 17968 - Maximum Engine Speed Exceeded

17968/P1560/005472 - 17968 - Maximum Engine Speed Exceeded (Engine Warranty VOID! ☺ )

Possible Symptoms
## Abnormal Engine Noises

Possible Causes
## Rev Limiter Removed, check to see if ECM has been 'Tuned'.
## Engine Speed too fast due to a mis-shift or the "Money-Shift".
## Stuck throttle.

Possible Solutions
## Clear Fault Codes
## Remove Lead from Foot

Special Notes
## This DTC indicates that the Engine Speed has passed the recommended safe RPM limit, which may potentially cause severe engine damage.


I don't know if this will help.

[nigelw1982]

have cleared the fault codes and it returns even after a gentle responsible drive looking in elsawin it just says over revving and doesn't give any indication to weather it could be a crankshaft sensor or something similar. there is no abnormal engine noises sounds sweet as a nut gonna do a wet and dry compression test on the internals see is theres anything untoward going on but i don't think there will be bonn check all resistances injectors and crank and cam sensor connections try and rule out as much as i can change the fuel filter in case its being starved of fuel throttle body been stripped down cleaned and new gasket fitted and re coded to match i dont know weather its been remapped how would i check that and the will check the rev limiter after all internal test have been carried out

[nigelw1982]

all injectors are around 18 ohms stone cold engine tested outside not at room temperature all spark plugs checked all bosch super4's and of good condition, checked the hall sender 4.5v on pin 1 good earth on pin 3 0v on pin 2 should get battery voltage on that but will know more when i run some more test with VCDS. good resistance on the air injection supply 31 ohms, checked coils good earth on 4a 3.0 ohms on each of the coil packs

compression pressures
1= 110 psi
2= 120psi
3= 110psi
4= 120psi
5= 105psi
6= 100psi
7= 100psi
8= 100psi

all these compressions were carried out on a stone cold engine not at min oil temperature of 30 degrees (what elsawin requires) or operating temperature dry of fuel as a problem with fuel line awaiting delivery of a new replacement.

[Delboy]

Sounds like you have checked all the boxes as it were, one question though. You say pin one has 4.5v and pin has nothing.

I haven't read elsa win but is that correct. I would have thought there would be ov, supply and feedback that ideally you would need to check with an oscilloscope?