I recently had my knock sensors replaced as part of an ongoing effort to eliminate a slight, random misfire and it helped but not entirely solved misfire. Shop noticed the knock sensors wiring harness was very fragile and so I just had that done about a week ago which also helped but again not entirely solved yet.

my question is regarding the mpg/kpl is now so terrible also with blackened exhaust tips. No codes of course but worried about the cats.

specs say avg per 100km should be around 12.3ltrs but that was when new about 13 yrs ago. Before those parts were replaced I was getting better average consumption, maybe 17ltr per 100km with nice light brown tips is it just a case of waiting for the ecu to self adjust?

ps when I release the petrol cap door it flies off the little lever and was wondering how that is supposed to held on the slide?
Thanks

 

Mine is 20-22l/100km but I never drive mine economically. 5.0 supercharged. If I'm doing a road trip on motorways I tend to get a combined average of 12-14. If you are pootling around town and getting those consumption figures then check your fuel trims! I would also suspect an injector on the way out.

 

What on earth is this kilometer/litre crap. lol
I fill my tank. Range - about 325 miles. avg mpg is 16-17 (mostly traffic driving under 50mph).

 

For the ROW 17mpg = 13.836 L/100 km

 

The international standard for fuel consumption in the modern age is l/100km.

 

Yeah, USA stuff is all Third World ****-hole stuff now. We're a joke now on the planet.

Anyway, I usually show 320 Miles after a fill up.

 

Take the car on a highway on cruise control and reset the km/liter reading run for 10-20 miles and see what you get. On my 4.2 XKR I get 9-10L/100k at 120kph on the highway. Around town around 14-15 liters depending on how long I'm idling in traffic.

Get a code reader and check the fuel trims.

 

This has actually been a thing bugging me.
i have the Veepeak Bluetooth connected to my phone and displaying thru the car scanner app.
I monitor 3 things:
coolant temp and both LTFT.
When I got the car in August, it idled near zero.
Peaked just under 2.
Slowly over time it started creeping up.
Idle @2 and peaked at 3.5.
Then idle at 2-3 and peak 5.

I know as long as it isn’t 10-15 it isn’t an issue, but sure feels like it’s going that way.

 

""I was getting better average consumption, maybe 17ltr per 100km with nice light brown tips""
Alanroberts, 17 liters per 100 kms is NOT better than 12.7 liters per 100kms.

 

correct, it’s better than the 20/100 I put in the title.

 

Comment on fuel trims.

LTFT target, as everyone here knows, is 0. Ranging +5 to -5 is just fine and probably not worth chasing, but past that it's time to take a closer look as to why.

Increasing positive means the ECU is adjusting for a lean condition, and is often a vacuum leak.

Increasing negative means the ECU is adjusting for a rich condition and is often a leaking injector.

Of course, the above are just examples. Other things can cause the variation in the LTFT

If I remember correctly, SES light goes on at +/- 18-20 on the NA 4.2. Not sure on the 5.0 or R's.

 

Thanks. Read a convo about this a long while back.
I’m not super concerned, but as it has been slowly trending up (+), albeit slow, when I get my motor/trans mounts done here soon, I’ll have them do a vacuum test. May be small, but I’d rather catch it now.