GQ 4.2ltr EFI fuel economy issue

Submitted: Sunday, Jun 05, 2005 at 19:14

ThreadID: 23607 Views:2758 Replies:2 FollowUps:3

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Bryan (WA)

Hi All,
my 4.2l EFI GQ patrol about a month ago suddenly has decided that it wants to drink lots more fuel than it used to. It has started using approx 2l/100Km extra around town and on country runs. The motor still idles smooth, Im not blowing smoke, and Ive done the usual basic checks - timing is fine, air cleaner and fuel filter changed, checked spark plugs and they are clean (only done 6k since its last service). I havent lost any power and I can go right through the revs with out the air warning lamp coming on.. I pulled the battery of today to reset the ECU - not sure it that will reset it so it has to learn again..

Has anyone else got any idea's on what it might be or what else I should check.. basicly the car is running perfectly and nothing has changed.. It suddenly deciced to drink more fuel - which is a bad thing :-(

thanks for any advise or responces.

regards
Bryan..

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Reply By: Willb - Sunday, Jun 05, 2005 at 19:56

Sunday, Jun 05, 2005 at 19:56

Hi, could be fuel injectors need a clean, also fuel quality makes a big difference. Have you changed your supplier recently?
Will

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AnswerID: 114462

Follow Up By: Bryan (WA) - Sunday, Jun 05, 2005 at 23:07

Sunday, Jun 05, 2005 at 23:07

Hi Will,
I always use Woolworths fuel which is Caltex fuel.
I tried a fuel injector cleaner in a tank, but that diudnt help either :-(

FollowupID: 370375

Follow Up By: Truckster (Vic) - Sunday, Jun 05, 2005 at 23:19

Sunday, Jun 05, 2005 at 23:19

No offence, but I wouldnt use woolworths fuel if it was free... have had issues personally with things like this happening back in my Ute as well as power flucuations.

I stick with the local the Shell dude, and Mobil cause they are handy, but never buy from dodgey brothers or no namers.

FollowupID: 370376

Reply By: Swine Hunter - Monday, Jun 06, 2005 at 04:14

Monday, Jun 06, 2005 at 04:14

Hi Bryan,

I would not think that injectors are the problem particularly if idle and WOT are smooth and no smoke is visible, plugs are clean etc, a dribbling injector will usually be quite apparent once you compare all the plugs.
Try the O2 sensor, if faulty could be telling the ECU exhaust gas is too lean and needs more fuel. Try pulling codes from the ecu (use paperclip straightened on 2 pins of the diagnostics plug near the bonnet release lever, not sure from memory which pins, if you get stuck I can look it up for you from the manual.

Cheers,
Wayne

AnswerID: 114500

Follow Up By: Bryan (WA) - Monday, Jun 06, 2005 at 21:33

Monday, Jun 06, 2005 at 21:33

Hi Wayne,
how would I know if the o2 sensor is faulty?
Maybe I should book it inot a nissan dealer to have the ECU and th eo2 sensor checked?
how do i check the codes on the diagnostic plug? and do you have a list of what the codes mean?

regards
Bryan

FollowupID: 370512