AU track car, running overly rich, need direction

[XF_Pilot]

Hi guys.

I have an AU XR6 HP track car. On a recent track day I was shocked by its fuel consumption. Now I am not expecting good fuel consumption on a race car but it used noticeably more than on a previous track day.

It also felt a little flat down low, probably due being over rich.

When I got home it wasn't idling well and I pulled the plugs out. Jet black, covered in dusty soot etc. The car is also spitting black soot from the exhaust (not cat).

The car has a stock HP engine, straight through exhaust, extractors and no cat. Cold air intake with pod and nothing else.

I ran the codes, initially a few came up. However I cleared them and all that came up was the air con and emissions charcoal valve came up (both have been removed).

I cleaned the plugs and the ISC, which helped the idle but still rich.

I also noted that the fans weren't running so I thought maybe the Head temp sensor was out of spec causing it to think it was cold/run rich and not turn on fans. This was perfectly in spec though.

I am looking for any other ideas as to where to go next.

[XF_Pilot]

Hi guys.

I have an AU XR6 HP track car. On a recent track day I was shocked by its fuel consumption. Now I am not expecting good fuel consumption on a race car but it used noticeably more than on a previous track day.

It also felt a little flat down low, probably due being over rich.

When I got home it wasn't idling well and I pulled the plugs out. Jet black, covered in dusty soot etc. The car is also spitting black soot from the exhaust (not cat).

The car has a stock HP engine, straight through exhaust, extractors and no cat. Cold air intake with pod and nothing else.

I ran the codes, initially a few came up. However I cleared them and all that came up was the air con and emissions charcoal valve came up (both have been removed).

I cleaned the plugs and the ISC, which helped the idle but still rich.

I also noted that the fans weren't running so I thought maybe the Head temp sensor was out of spec causing it to think it was cold/run rich and not turn on fans. This was perfectly in spec though.

I am looking for any other ideas as to where to go next.

[PridenJoy]

Possible O2 sensor

[Maka]

Inlet manifold gasket, fuel pressure regulator (rare), cyl head temp sensor, o2 sensor. O2 sensor may not show up on a scan afaik.

Put your dash into diag mode & see what the running temps are, over 80degc the radiator fans should start working when stopped, pull the wiring connecter on the cyl head sensor or put your air con on flat out to see if the fans come on full blast, will show if sensor is ok, good luck!

cheers, Maka

[XF_Pilot]

I have never used the diagnostic mode, I'll give that a shot.

The problem is I have removed all the air con including wiring so I can use that as a test.

I was told that the O2 sensor was only used for idle and cruise not for power as timing maps were used?

[Maka]

Temp sensor will still tell the ecu to turn on the fans due to running temps, removing air con stuff shouldnt matter imo.

When i changed my o2 sensor full drivability & power was restored all through the rev range, worth a shot imo. How old is your fuel pump?

cheers, Maka

[XF_Pilot]

Ok that's interesting. Well I'll test it, I just need to find the resistance range.

The fuel pump us new because that was causing issues before. New fuel filter. New ignition.

I have read that a blocked injector rail filter? Can do this or maybe a pressure regulator?

The fact that the fans aren't coming on suggests its new likely not that. Unless by removing the air con or something I have upset the wiring. they physically work if I connect power direct. I'll swap over some relays

[Maka]

Could well be rust blocked filter in the fpr, especially if e10 was used alot previously imo. It can rust out the insides of the fuel rail, has happended to other AU owners in the past. Pull the fpr if e10 has been used extensively in the past, if not, leave till last thing to check imo.

I was just enquiring about the fuel pump, usually people will leave it till last when troubleshooting lol.

cheers, Maka

[XF_Pilot]

Yeah I was chasing a few issues when I got it and fuel pump ended up fixing a lot of them.

I don't know much about the fpr but ill do some reading and maybe open it up if it's straight forward

I will test the oxy sensor too, just need the operating resistance.

[Maka]

I've pulled a AU i6 fpr apart chasing a odd misfiring issue a couple years back in my old Futura & it was relatively clean (no e10 use) with around 300,000km use lol.

I couldnt reuse the old one once pulled apart though so just got a wrecker special to try & it was back to normal running once i reinstalled it. Didnt fix the original idle miss issue, bugger lol!

Also, just checked my Ellerys & no resistance values given for the o2 sensor unfortunately, was yours replaced with other components of the ignition system you said earlier? If so, its probably still good but if youve never replaced it, do it asap imo. Hope this helps abit lol!

cheers, Maka

[FERG_51]

Check fuel pressure, if high you may have a blocked fuel reg or return line

[XF_Pilot]

Thanks for the information guys. I have a new o2 sensor on order and will be removing the FPR this week for a clean out. Will post the results. THanks

[falcon_bandit]

Originally Posted by Maka

fuel pressure regulator (rare)

on an ageing falcon 6, a faulty reg is quite common

have rail pressure tested inc leak test for injectors

[Maka]

[QUOTE=falcon_bandit;5980819]on an ageing falcon 6, a faulty reg is quite common have rail pressure tested inc leak test for injectors QUOTE]

Yeah ok tbh i dont see that many AU i6 owners on Google or AFF search suffering from a blocked fpr lol even if they use e10 exclusively imo.

Also theres no shrader valve on a AU i6 fuel rail & the fuel rail is different to E series Falcons.

But for sure, its a good idea to test fuel pressure if you can rig something up.

cheers, Maka