Fg ticking/knocking problem?

[Fgturbro]

Hey Guys

 

So I recently brought an 08 FG turbo off a guy from facebook, stoked as with the car driving it home (about an hour and a half from where I live) I made the mistake of putting 91 in it I assumed it wouldnt be a problem bc I owned a ba xr6t prior and it ran fine on 91, anyway it drove home fine come the next day I drove it around in the morning to show one of my friends and when I went to leave I started the car and when I put it in Reverse it stalled all of a sudden (yes its Auto) to my frustration I ended up getting it to drive again and once I got it on the road I gave it a bit of sh*t and managed to get it to my friends house around the corner, I took off throttlebdy looked clean so I took the AFM out and cleaned that also put it all back together and it ran perfectly for about 5 mins then stalled again once it went under 1k rpm. I talked to the previous owner about it and he said hes only ever run 98 So I thought it may have been something to do with 91 so I filled the rest of the car up with 98 thinking it may have been tuned to just 98/95 and put some octane booster in there managed to get it to idle with out stalling then after about 20 mins I gave it a little rev and I noticed it started making a knocking kinda noise around 3k rpm. I brought an diagnostic reader and it doesnt come up with anything on there and im starting to freak out abit. Has anyone got any advice or how to go about fixing this and if it is a knock whats the best/cheapest way to fix that?

Cheers in advance 

[k31th]

 

Sounds like it was tuned at some point (hence using 98 all the time)... did it come with a tune box?  If it's tuned for 98, you'll have to run it off boost until you run out of the 91 in the tank, as mixing in 98 won't help until it's mostly up to 98.

 

A general piece of advice... if your car behaves badly for whatever reason, giving it full throttle is the last thing you should do in that circumstance.

 

FYI, also there's no "AFM" on these cars, it has a T-MAP sensor (Temperature, Manifold Air Pressure) and it's located on the inlet manifold. The sensor on the throttle body is a TPS (Throttle Position Sensor).

[Fgturbro]

Didnt come with a tune box as far as im aware, my tank is full up with 98 now so do you think I should drain it completely and put some new 98 back in?

[k31th]

yes, you "filled" the tank with 98, but did you "fill from empty" ? until it's "filled from empty" or completely 98 and it's tuned for that, it won't be a good idea to hit boost.

Obviously draining and putting in 98 will resolve the fuel problem quicker, but it's not an ideal way to go about it in terms of cost etc.

[Fgturbro]

How do I go about that will I have to remove the whole tank and hook a battery up to the fuel pump? Or is there an easier way

[k31th]

if you want to drain it, you can bridge the fuel pump relay and disconnect a fuel line straight into a petrol storage container (or two) if you don't want to throw away the fuel... but you shouldn't need to do that, just drive it off boost until you fill up a 2nd time and it should be very close to completely 98.