I have just installed this with an LC-1 hopeing to keep an eye on adverse conditions when using nitrous and my preditor 93 tune. Trouble is, I dont really know what is normal. so far I'm reading 14.5-15 at idle and normal driving. If I rev up to about 3k or lay in a little foot down the road, it quickly shoots up to almost 17. This is without even using nitrous. I thought ideal was to remain around 14.7 at all times?
No. 14.7 is what you want cruising around. Maybe 12.2 to 12.5 at WOT? 17 sounds serious. I think you're going to do damage or something is not right with the gauge. WOT is an open loop mode. The PCM uses fixed values and adds some fuel (I believe one of those values is the long term adaptive but it's not updated in that mode). Just cruising around is closed loop and the input from the narrow bands is used. The PCM will constantly "hunt" for 14.7 by adjusting the injector pulse width. Short term adaptives are used along with the long term adaptives and the short term adaptives are used to update the long term adaptives. That's why you see the gauge constantly bouncing around. WOT and you should see a pretty steady value, and 17 sounds very very bad.
At idle, and during normal driving, it will hunt at 14.7:1. during some off-throttle events, it'll spike up - perhaps even off the scale where it will flash "o2". That's normal - as the car has turned off most fuel for engine braking. During full-throttle only, you are looking for about 12.8:1. On nitrous, I'd tune to 12.0:1 - or even richer like 11.8:1. 17.0:1 is wrong, unless you're seeing it when you lift off throttle. If you see that with the car floored - STOP IT. Use a Predator to add fuel. Big time.
This might be a bad time but... maybe when you get this worked out, a separate thread with where you ran the cables from the sensor to get to the gauge?
I'm not sure how the 6.1 PCM does it, but my PCM hunts for 14.7 until I hit 82% throttle. Then it goes into it's WOT fuel maps and I run 10.0 AFR's....uber-rich. (I'm still untuned) I would imagine your is basically the same. So, just blipping the throttle will not cause a rich condition, and as the motor winds down from 3K or so, it will show a lean condition.
Yep I answered this question on chargerforums.com but this is all the same. Just don't listem to Ron if he posts up. He has a bad habit of blowing engines...
Ok, my sensor is using one of the rear factory 02 bungs with the rears turned off by the preditor. I'm not sure the guage is working properly(new). But it seems quite unlikely for a malfunctioning guage to go up when it should be going down. my tune is the canned 93 CAI which adds more power yes ,but on the rare occasion I really get on it, (no nitrous) it often bucks , cutsout or hesitates, both at gear change and in between. Several curious things this motor has done for awhile that dont get serious attention when reported to the dealer. Why? because the car runs fine under normal driving. 1) fuel presure seems low- whenever I disconnect the line, i'm lucky to see a drop.Never has there been a squirt as warned do to presure build up. 2) severe lag fromdig (before pred) now buck, cutout hesitate at wot as mentioned above. 3) 1 year and several bottles and I have yet to notice any added benefit from nitrous. I believe a lack of FP causes the zex protection sys to hold back the O2.
The sensor should be installed as close to the collector as you can or it will read leaner than it actually is. It will definitley read leaner if it is after the cat.
Do you think that explains the high #s like 17? I've heard of several using the rear o2 bung but never read any complaints like mine
Could very well be. Not sure why others haven't had a problem unless they didn't have cats. Maybe one of them will chime in.
I think with nitrous and everything (even without) you should bite the bullet and have another bung installed before the cats. People say any muffler/exhaust place can do it for around $50? I'd think you really want accurate readings for your application and especially since you're having problems.
howdee - like others are saying, the sensor should be before the cats. as for the bucking and hesitation...... that does not sound right at all. what version are your running on your pred????? i found version 17 was the best performing of the bunch for me.
My A/F is plugged into the bung after the cat....I have run with cats and w/o cats (current condition)....I never noticed any diff between having a cat and not as far as A/F readings go.....I would be terrified if my guage went to 17 at WOT....a blown engine is in your future if you do not get this taken care of....BTW..Ron can tell you where to get a good deal on a new engine...he has bought 2...:tropicalwind:
running 17 also. I had a shop tell me there wasn't enough room to get a drill in there so he wouldn't do it. I guess i'll have to take the mid pipe off and do it myself on the bench.
