Evan G Posted September 6, 2010 Report Share Posted September 6, 2010 (edited) gday all, i recently got my jaycar o2 gauge working and these are some of my readings. I'm running the standard aisin carby What does it show at idle? 9.5 What does it show at a constant 60kph? 10.1 What does it show if you left off a fraction? 9.8 What does it show when you lift right off and are on over-run? 8.5 What does it show if you ease the throttle on? 10.1 bang on the throttle = goes down to 8.5 then back up to 10.5 doesn't change with the choke on? i thought it was my air filter, so i ripped it off but the readings didn't change Ive tried 2 different o2 sensors and I'm still getting the same readings. I'm chewing through fuel. timing is on 15degrees advanced. I'm running some torquey cam. carby has been rebuild and was running well on my other daily. on the last cruise through the hills, felt like the car was bogging down HARD when going up the tight steep turns. why soo rich? something doesn't sound right at alllll! ke55 4kc, rebuilt engine. 60 thou oversized pistons and a torquey cam, electronic dissy Edited September 6, 2010 by Evan G Quote Link to comment Share on other sites More sharing options...
Tazrolla Posted September 6, 2010 Report Share Posted September 6, 2010 (edited) 1st of all what car is it? 2nd and this is only a general rule for tuning a carby turn you fuel mix screew full in and undo it 1 1/2 turns.. it wont be spot on but is a good advarage starting point then find out if it leen or rich and adjust 1/4 turns at a time to get it right but before you do that count the turns you do the mixture screew up so you can fall bk on it ofcoure some1 will prove me wrong but thats what i was told to do years ago on mine and it worked for me However it was on a crappadore (don't hold it against me) :laff: *edit* i should note i don't know what car ya got unlike most of the other people on here :rolls: *another edit* :bash: isnt 15° too advanced (again not knowning what the car is) shouldnt it be around 8-12°??? Edited September 6, 2010 by Tazrolla Quote Link to comment Share on other sites More sharing options...
Evan G Posted September 6, 2010 Author Report Share Posted September 6, 2010 (edited) sorry forgot that bit ke55 4kc, rebuilt engine. 60 thou oversized pistons and a torquey cam ive adjusted the idle mixtures (screw it in till it runs rough then back it off half a turn). this shouldnt have any affect on how rich/lean the engine runs through the rev range as its only the idle mixtures correct? edit - it ran like a bag of poo on 10° with 98. so i put 95 octane with 15° runs ALOT better. Edited September 6, 2010 by Evan G Quote Link to comment Share on other sites More sharing options...
Tazrolla Posted September 6, 2010 Report Share Posted September 6, 2010 ok wow 15° just seems like a lot do you have an adjustable cam? and I'm asuming that you timing (belt/chain) are spot on and not 1 tooth out?? as well as the dizzy (soz never played with that engine type b4 but guessin much the same as a 4A-C (forgive my noobness) I'm thinking that your engine might be retarded(not calling it retarded) eg; 1 tooth b4 tdc hence having your timing advanced to 15° Quote Link to comment Share on other sites More sharing options...
Evan G Posted September 6, 2010 Author Report Share Posted September 6, 2010 ok wow 15° just seems like a lot do you have an adjustable cam? and I'm asuming that you timing (belt/chain) are spot on and not 1 tooth out?? as well as the dizzy (soz never played with that engine type b4 but guessin much the same as a 4A-C (forgive my noobness) I'm thinking that your engine might be retarded(not calling it retarded) eg; 1 tooth b4 tdc hence having your timing advanced to 15° nah buddy non adjustable cam (its a k motor damnit :rolls:), i was running 15° on my other 4k aswell i had bamboo (a former mechanic now pushing a pen :bash: )around my joint when we timed up the dissy. cylinder 1 on fire and the rotor button pointed to cylinder 1. Quote Link to comment Share on other sites More sharing options...
Tazrolla Posted September 6, 2010 Report Share Posted September 6, 2010 ok one last idea... :rolls: do you have another carb ya can try on ther and do a o2 check on it twin su's :bash: even better Quote Link to comment Share on other sites More sharing options...
Evan G Posted September 6, 2010 Author Report Share Posted September 6, 2010 ive tried another o2 sensor but get the same readings :rolls: i want to fix the problem as ive just rebuilt this carby Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted September 6, 2010 Report Share Posted September 6, 2010 Just for arguments sake... Compared to my SUs. What does it show at idle? 9.5 +5.2 = 14.7 I set mine to 14.7 dipping into 16 & back. What does it show at a constant 60kph? 10.1 + 5.2 = 15.3 Between 14 and 15 for me. What does it show if you left off a fraction? 9.8 + 5.2 = 15.0 Leans off to 15-16 or so What does it show when you lift right off and are on over-run? 8.5 + 5.2 = 13.7 Flicks rich, then leans out to 17 or 18 What does it show if you ease the throttle on? 10.1 + 5.2 = 15.3 Goes rich a little 13 or so. bang on the throttle = goes down to 8.5 + 5.2 = 13.7 Goes rich! 11 or 12... then back up to 10.5 + 5.2 = 15.7 Back to 13 if I'm still accelerating. So even if it was a matter of calibration, yours hardly moves compared to mine. We've got the same Jaycar meter, but I suppose the O2 sensors are different. Mine are VT Commodore narrowband 4wire ones. If its the stock Aisin carb it should be about right for the car, unless the cam really upsets it. What happens if you move the FMD calibration up 5 points?? I'm going to get mine run against a garage's to see if the calibration is about right. The guy who checked the SU needles on a dyno said the were just fine right through the range, which is OK but a bit vague.. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted September 6, 2010 Report Share Posted September 6, 2010 (edited) Oh- I'm gettting about 10L/100km around town, and 7.4 on a trip. Worse than stock, or using the 'lean' needles, but a lot quicker to drive! :rolls: Strip the carby and check everything again! I've loaned mine ('83 KE70 w antipollution stuff on) out to Rob for his KE55 and he reckons its much slower than the old mechanical 2nd throat he had. There's obviously a lot more wrinkles in the stock carbs than we expect! doesn't change with the choke on? ..and that's got to be a worry! You can set the richness on mine using the choke... we did it on the trip to Melbourne with the lean needles in! Edited September 6, 2010 by altezzaclub Quote Link to comment Share on other sites More sharing options...
Evan G Posted September 6, 2010 Author Report Share Posted September 6, 2010 (edited) wait now you've confused me, where did you get the 5.2 from? Ive got a spare carby around here some were, ill slap it on the week end and do some experimenting. its still doing daily duties Edited September 6, 2010 by Evan G Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted September 6, 2010 Report Share Posted September 6, 2010 lol! I just added that to make the idle 14.7... Any random factor would do. We can't compare the actual numbers unless we synchronise the two meters somehow, but we can compare the way they change. Next time I'm in Melbourne.... Quote Link to comment Share on other sites More sharing options...
Evan G Posted September 6, 2010 Author Report Share Posted September 6, 2010 post me your gauge to borrow :rolls: Quote Link to comment Share on other sites More sharing options...
Trev Posted September 6, 2010 Report Share Posted September 6, 2010 You might wanna check your plugs too. Quote Link to comment Share on other sites More sharing options...
Andy43 Posted September 8, 2010 Report Share Posted September 8, 2010 Evan Sounds like the calabration of the Jaycar kit it wrong. How did you setup with the 1volt source ? as the lambarda sensors only work in a very short range. Quote Link to comment Share on other sites More sharing options...
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