jas98 Member 1,043 Member For: 12y 5m 2d Gender: Male Location: Maryborough Qld Posted 28/10/22 12:45 PM Share Posted 28/10/22 12:45 PM Hi all. Trying to find cause. Ba xr6t. Few week back car just started have random miss at idle or taking off. Took home had codes for TPS and throttle pedal sensor. Oxygen sensor. . So swapped TPS and O2 sensor and was all good for a little bit. . Last week noticed that car had slight miss at idle again. And was idleing higher (slightly .like 50rpm ) so hooked forscan up and had 3 codes for oxygen sensor. So though we'll the one I swapped with maybe it was I <3 Bananased. So bought new Bosch one. Came good perfect. Drove it couple days but I <3 Bananas then noticed it was drinking fuel .. Today for 1/4 tank it only done 62ks.....can smell it running Rich and has a oxygen sensor code lean. ...no other codes But when was on forscan noticed O2 sensor was at .85 volts and steady and also it's stuck in OL-fault. It did switch to open loop for about 20 min while driveing and ran smoothly but then while cruising home at 60 kph it droped back to OP-fault. Seems to be stuck in this OL-fault mode hence why it's drinking fuel Now over last few months I've replaced every sensor and injectors etc as I wanted to change Al those but I'm not ruling any sensors etc out. They were not eBay junk either though. I've read a bit and seems it could be the coolant/head temp sensor? Or fuel pressure/injector. I've checked the fuel reg (it's also only few weeks old) and fuel pump is about 6 months old no vacume leaks I did do a Kam reset through forscan which I've done before without issues so hopefully that hasn't caused any issues as I did this after I did the TPS sensor Any suggestions would be great. It's gone from useing about 14. Lph round town to now 24 lph round town and climbing Link to comment Share on other sites More sharing options...
jas98 Member 1,043 Member For: 12y 5m 2d Gender: Male Location: Maryborough Qld Posted 28/10/22 09:05 PM Author Share Posted 28/10/22 09:05 PM So have had allok. Can find any broken wires or leaks ...fuel reg checks out ok. Have thought and seeing the O2 sensor code it has now it a lean code and system defaults to OL-fald and not closed loop etc. Maybe injector stuffed so computer is just pumping fuel in so it doesn't lean out? Or even fuel pump weak? I know in therory it shouldn't as yeah no fuel through would mean your saving fuel but if computer sees it lean it will hold the injectors open more/longer?? Otherwise if it had a air leak it would idle hell high but it's not and can find any leaks while running Link to comment Share on other sites More sharing options...
Puffwagon Puff Gold Donating Members 15,988 Member For: 9y 10m 26d Gender: Male Location: South Australia Posted 28/10/22 11:22 PM Share Posted 28/10/22 11:22 PM A small air leak wont make it idle high. The car uses timing to change the engine idle speed so a vacuum leak will result in very low idle timing. Air leaks will hide in hoses in the form of cracks and it is fairly common to see them between the manifold and head and in the manifold halves. There could be a blocked injector, you can remove them and swap the filter baskets pretty easily. If you think it might be the CHT then check the output of the sensor with a scanner. Link to comment Share on other sites More sharing options...
biddie_fiddler [IMPULSIV3] Donating Members 1,374 Member For: 5y 8m 26d Gender: Male Location: Perth, WA Posted 28/10/22 11:49 PM Share Posted 28/10/22 11:49 PM Misfires generally occur from fuel, or spark. Have you checked the plugs and coil packs? Link to comment Share on other sites More sharing options...
cat007 Member 236 Member For: 6y 3m 21d Posted 29/10/22 12:11 AM Share Posted 29/10/22 12:11 AM Raw fuel can make an O2 sensor read lean. Link to comment Share on other sites More sharing options...
jas98 Member 1,043 Member For: 12y 5m 2d Gender: Male Location: Maryborough Qld Posted 30/10/22 06:14 AM Author Share Posted 30/10/22 06:14 AM Thanks all. Swapped injectors and reset battery ...thought I was onto something as it idles fine...O2 sensor was fine and reading as it should ...so let it idle for 5-10 min and as I was walking back (when it was warm) I herd it missfire and revs dropped like a mover starving for fuel and it shot revs back up to like 2500 RMP for a couple seconds and slowly idled back down...at this point is idled rough splutted and then started idleing again..although little miss . When this was happening the O2 sensor reading was spazzing out like it was loosing power ...gaining power instantly etc. .. After inlet it idle while it was little rough and wiggled all wireing I could see/get to without burning myself etc and nothing changed Turned it off and yanked the battery cables a little and started it and it seemed fine again.......prob a coincidence as it does come good sometimes Question can a bad engine earth strap cause this...like can it cause stupidly high fuel usage??? And these symptoms. One other thing I noticed was the air con jist randomly tirned off as pulling into driveway when I hit a bump aswell which it never has done that and it also did it in the driveway while this was all happening aswell Link to comment Share on other sites More sharing options...
jas98 Member 1,043 Member For: 12y 5m 2d Gender: Male Location: Maryborough Qld Posted 30/10/22 08:51 AM Author Share Posted 30/10/22 08:51 AM Also just rescanned for codes and none in pcm but did have a low battery code in bem battery is fine though and yes tested etc it's fine Link to comment Share on other sites More sharing options...
BarraT Member 34 Member For: 4y 11m 5d Posted 18/03/24 09:45 AM Share Posted 18/03/24 09:45 AM Hi, Jas98, did this issue get sorted in the end ? can we please post the solution for us , Thanks heaps Link to comment Share on other sites More sharing options...
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