BA XR6T RUNNING RICH

[stancez]

No I mean stock as in base boost etc accounting for the injectors. Just grabbed a FPR will swap it out in the coming days.

Did a log on the way to work, the 02 was hunting all over the place unless I take my foot off throttle and then it sit about .078

Long fuel trims hunted for a while and then sat at 0%. And the short trims were all over the place and then would sit at -18.79% and go up when more throttle was applied.

 

Here's a screen shot of the log from Forscan last night.

 

https://www.instagram.com/p/CTNSJhvhbTF/?utm_source=ig_web_button_share_sheet

Edited 30/08/21 05:54 PM by stancez

[El Andrew]

So sounds like the car is pulling a ton of fuel out!

If the car was fine for a long time after the tune and something has gone astray since, my money is on the FPR or a fuel return restriction.

Temp affects fuel strategy but you should be able to use Forscan to see if the CHT output looks sensible.

[stancez]

Did another log on the way home from work,

 

https://www.instagram.com/p/CTO1Wqah5S1/?utm_source=ig_web_copy_link

 

Drove alot better than it has for a while fuel trip still continues to come down, its only when on idle it's having the issue. I heard that the factory fuel rail can rust over years internally and gunk up the fpr, hopefully it'll be that or the return will see this week.

Only thing I noticed is the whole time it stayed in the open loop which I'd think is odd as open loop is the ecu not taking reading from the 02 correct?.

[El Andrew]

Correct, open loop us when it ignores the O2 sensor and just relies on the fuel maps, so no sensor feedback to make corrections.

It's also weird before that you had big STFT but LTFT was staying at zero - looks like it's not adjusting LTFT obvious because it's staying in open loop.

Need someone with more knowledge here to weigh in but either a) the sensor outputs are way out so the PCM is ignoring them (so some underlying fuel system issue) or b) some other failure is preventing the car switching to closed loop after the initial warm up. I'm thinking aloud here though.

Did you check Forscan for cylinder head temps? If that sensor had failed and was defaulting to its lowest temp range, car might stay in open loop.

Weird that you don't have a check engine light - have you scanned for codes?

[stancez]

Yeah checked, for codes nothing significant, and have also checked the CHT and it's nominal at 90c. The open loop occurred only after changing to this new O2 sensor. The LTFT are adjusting and after a while, cruising at about 80kph it'll sit.

 

Notice in the last pic the STFT had improved significant also. However the voltage on the 02 sensor still is showing to high voltage when the car is coasting or at idle which is when fuel trims go out the window and the car starts using more fuel again. Hopefully the FPR will get here by the weekend and I'll install it to see how it goes.

[stancez]

Did another log to work still in open loop decided to check fault codes again, now I have a pcm fault. Reset the pcm car went back to closed loop for about 1min and then went back to open loop again, fault code hasn't shown up yet.

 

https://www.instagram.com/p/CTPsdDqBzCw/?utm_source=ig_web_copy_link

[jas98]

Hey mate I have similar issues and also this exact code on my ba xr6t now Aswell.

 

Mine was open loop faulting. I tracked that to bad oxygen sensor wireing....fixed that. Change oxygen sensor Aswell. But also had TPS... throttle pedal....and 2 other oxygen sensor codes that I couldn't get rid of no matter what I did till I swapped around the ess(?) Relay and came good but the p0172 code I am yet to get rid off and it's using a fair bit of fuel again 

 

 

What I'm about to try is the CHT sensor as it's reading that it's at 1/4 on guage no matter tragic the jumps up a little then down just as quick. 

 

..other thing is I was gonna check vacume leaks again and also fuel pressure return restriction in line as the FPR is fine/new. 

 

 

 

 

Don't like using bucket loads of fuel haha

[stancez]

Hey mate yeah I still have the issue have the issue the last thing I did was replace the the fuel pressure regulator and it still does it.

I work FiFio so the car is parked up majority of the time these days. Think I'm going to have to bite the bullet and take it to a shop to have them diagnose the issue.

[BarraT]

Can we post up what the solution to the issue was ? Thanks heaps

[stancez]

Hey mate, I ended up taking it in to have it professionally looked over, they took two days to figure out the issue was, it wanst making any power 200rwkw so the tuner took off the back half and she picked up 111rwkw, ultimately was a blocked muffler. I had a few other things done and got the car back with 320rwkw.