untuned sound???????

[hold-on]

nothing to do with road, dirty throttle body and iac valve me thinks

 

[Jon Z]

Might even be the torque converter, it might be unlocking then locking up causing the change in revs or sound as you are describing, just my 2 cents

 

[hold-on]

how can I tell if it is the torque converter, went for an hour drive today ran diagnostics after code 12 did not seem to make the untuned sound. Checked throttle body afterwards and had carbon residue (not much) but from being completely clean and going for an hour drive should ther be any residue at all????? or is a bit normal!!!

 

[Jon Z]

how can I tell if it is the torque converter, went for an hour drive today ran diagnostics after code 12 did not seem to make the untuned sound. Checked throttle body afterwards and had carbon residue (not much) but from being completely clean and going for an hour drive should ther be any residue at all????? or is a bit normal!!!

Well if its the torque converter u can hear the revs change and the revs on the tacho will increase slightly while its unlocked then as it locks up again the revs will drop. If it is this and i dont really know if it is you will feel it too while driving. Mine was doing this at around 80's before i got it serviced as it was in need of a fluid change.

As for the carbon deposits after an hour driving i wouldnt think there would be that much but it could also depend on your valvetrain etc and how much fuel etc is getting back up into the top of the manifld etc. I could be wrong but its an idea

 

[hold-on]

okay say it was the torque converter how can I go about repairing / cleaning or whatever you do to it!!! the carbon despots were not much after hour of driving....... what do you think about the wrong oil viscosity 10/30 synthetic instead of 20/50. also a while ago one a cylinder was down due to spark plug I think the oily residue I found in throttle body could have been caused by one of the above what do you think??????

 

[holden007]

If your engine has high mileage (most of our cars do) then use 20-50W oil, 10-30W is to thin for a big old engine. I use Penrite 20-60W, runs beautiful and less noice (I used to use GTX2, some reason it's lost quality).