a few weeks ago i installed my wideband o2 and gauge lc-1 from innovate. The sensor seems accurate because i can cruise around at 14.7 with small fluctuations up and down .3 or less in both directions after warmed up..
Now the problem im having is when i go WOT in second gear the gauge pegs lean at 21.8 around 5000rpm and stays when i shift ... if i do a 3rd gear run it pegs 21.8 around 4500rpms and stays lean as well.. Is this something to do with the sensor or is it a whole different problem altogether?

Stealth ram with non adjustable regulator from holley.... I tried changeing the number to 42.5 from 37.5 to the power enrichment in that rpm area and moved my maf scalars up 20 clicks to see if it made a difference and nothing did?

 

Did you do the free air calibration before install?

 

yes which is why everything is correct when im cruising and matches up with tuner pro vs factory o2 (blm)
im wondering if maybe its the regulator?

 

what is the narrowband O2 saying when the wideband is saying 21.8:1?

 

good question, ill have to check that.. but i was under the influence its not accurate at all during wot

 

narrowbands are more useful than most people would like to admit....

 

if you moved the MAf scalars and such up and the wideband did not change, then something is wrong with the wideband, or atleast that would be my best guess.

You should have seen a change in air fuel at WOT with a big scalar change and PE change.

Only other thing that could explain that is that its MUCH leaner than 21.8 and thats the maximum it will read. The changes you made are still not showing up on the gauge. Could be the case, but I thought the LC1 only read from 10 to 1 air fuel to 20 to 1 air fuel. The equation output it uses is 2*V+10 = air fuel. So 0 volts is 10 air fuel and 5 is 20 air fuel.

 

There has to be an issue with the WB reading. At 21.8:1 AFR, the engine would not be running. Gasoline engines typically cut out above 17:1 AFR. The lean limit is usually in the 16.1 to 16.5:1 area. Which is good for light load lean cruise fuel mileage.

RBob.

 

i can agree with that... i have lean cruise set at 16.2:1 on both a 3.1 grand prix and a 3100 monte carlo, any leaner and you can feel a miss and the O2 freaks out.

 

Step 1. If you give the car 1/2 or 3/4 throttle with the rpms down low, what does the wideband read? If it reads good, see step 2. (If wideband reads lean but car feels powerful, wideband is suspect).

Step 2. When the gauge does peg at 21.8, how does the car feel? Really weak or still pulling hard? If it's real weak, I'm guessing you are running out of fuel (fuel pump or regulator suspect).

 

ive been working on the accel enrich because at times it will go to 18ish and stutter then enrichen up to 14's and feel strong (during 1/2 throttle accel)

when it hits 21.8 it doesnt pull anywhere near as hard but it does accelerate without stuttering/bucking at wot.


i did order a kirban afpr and will put it on as soon as it arrives

 

What else did you do to the car? Just a stealth ram swap? I would think the regulator is bad if thats the only change. Sounds like its closing off at WOT or just leaking all the pressure out, but I wouldnt expect it to run smooth at over 20 air fuel. My old 383 when first tuning was over 17 to 1 air fuel and ran fine at WOT but didnt feel as strong as i thought that motor would. Once I added fuel it came alive.

 

Sounds to me like your wideband is fine but you aren't getting enough fuel for some reason. You could try putting a rediculous amount of fuel in the PE vs coolant temp table and in the PE vs RPM table, then go floor it and see if it swamps rich or not. If it does, it is in the tune. If it doesn't, then your fuel pressure is likely low for some reason. You will need to get a fuel pressure gauge hooked to the schrader valve, then run it up and tape it to the windshield and go for a ride to verify low pressure. I'd guess the regulator also, at that point.

After you get the fuel pressure to hold (if that is indeed the problem), if you still have the problem on accel enrich and can't get it worked out completely with the accel enrich tables, you can always bring PE mode in at a lower TPS voltage and then tune that lean condition out with the PE vs RPM table. I know I got my accel enrich working great until about 1/2 or so throttle, then I couldn't get it rich enough for what I wanted, so I set the PE mode to come on sooner, then tweaked the PE vs RPM in the lower rpm areas and all is good. High load low rpm is where my car liked to detonate even with gobs of timing removed so I richened it up to like 12.0:1 at a 1/2 throttle low rpm lugging acceleration. Put some timing back in and it likes it that way.

 

it has a zz4 cam, headers, cai, full 3 inch exhaust, 4'" spiral flow muffler, !cat, rebuilt 305 .030 over, 1.5 rr, 21lb injectors

the only problem i have with adding so much extra PE is in 2nd it leans around 5k, 3rd around 4.5k, 4th around 3.5k, and 5th around 3k rpms... this is with a 2nd only, 3rd only, 4th only, or 5th only gear run... if i wot from a stop after 2nd it pegs lean permanently, and sometimes after 1st it will peg lean also


also another symptom idk if its related or not... during a completely cold start up, the first one of the day, it idles up and down and the a:f is lean when it idles during a 550 rpm dip, then when it saves itself it idles to 1600 or so and goes to 13's or 14's a:f then back down and repeats til it figures itself out... my idle when calm is around 16.4 or higher/lower sometimes...

 

I'm kinda surprised a mostly stock bin tune is going that lean with those mods. Cam/headers/HSR etc you would expect abit lean but certainly not from a stock 12-13 to 1 air fuel to over 21.8??

If this is the true case and nothing wrong with the wideband, then thats a good thing Means that motor is really capable of making good power and needs a ton more fuel.


Higher the gear, more load on the motor so it makes sense it would peg lean abit lower in the rpm range.

Is this open loop tune or closed loop? Have you looked at what the narrowband is doing?

If its closed loop, what are your BLMs/INT's doing when the wideband is reading high 14's to 1? If open loop, does it seem to stay around 14.8 or so air fuel during entire cruise rpm range and different LV8's?

If the wideband/blms are ok during your cruising under various LV8's, then definately start PE mode tuning. Does your MAF sensor max out 255 g/s at all during a WOT run over 5k? If not you can try to tune the MAF tables 4-6 to get your WOT fueling back in line but PE % vs RPM is much easier. Give it 20-30% MORE right now starting in the peak torque rpm area (3400-4000 rpm) and about the same 30% or so for 4000-6400 for now. See if that large change makes a difference in the wideband reading.

Probably going to fluctuate wideband readings in different gears because of the loading on the motor but thats ok. Just make sure 4th gear is happy since its the 1 to 1 gear and used for 1/4 mile and dyno tuning.

 

i had it almost perfect when i thought the injectors were 22lb, now that i changed them to 20.8 due to the fact that holley states a 43psi regulator its a bit rich in open loop at cruise... but when the ecm learns to take fuel then yes, highway is 15.3 like commanded, and town cruise barely fluctuates from 14.5 minimum to 14.9 max.. I havnt really messed with getting it close again because of the wot problem ive had before and after the constant change.

no the maf never hit 255, it started at 180's and when i slid the scalars i had it to 210ish but quit there... think thats the problem? should i be pulling that much air?

I just did a wot run and when the a:f said 21.8 the o2 said 972

 

Are you saying it was running almost perfect at part and full throttle when the injector constants were 22lb? If os, change the constants back to 22lbs and be done with it.

And you should see 255 gms/sec. I hit that reading in the middle of MAF table 6, and I have alot of fueling being added from the ol afr%change vs lv8 table (I run full open loop so it is always adding fueling from that table).

 

This is kinda contradictive. HIgher 900's mv from a narrowband is typically RICH. Maybe a wideband problem here... like its doing the reverse of what it should be doing.

Being a light cammed 305, I'm not sure its going to pull a full 255. If it does it would be up near peak hp. My 383 was able to max it out at 4500-ish rpm and it was probably near 330whp at that point and over 375lbft torque. I dont see your motor making that much power so its probably not going to max the MAF just yet.

Try verifying the wideband is wired correctly and that the output equation is right. Main signal wire should be programmed for 2*V + 10 = air fuel ratio. Recalibrate it in free air then screw it back in.


Before you do any of that, you can try to make the injector constants at 22 lbs again, and see what WOT does. IF it looks more normal air fuel wise, then if you wanted to use 20.8, you will need to add a bunch of fuel either in PE mode, open loop tables, or keep playing with scalars/maf tables. But based on the narrowband reading vs wideband, it seems to be doing the opposite.

 

dan- i tuned it with the 22lb constant then decided i wanted the correct constant in there... the only thing perfect was cruise blm/int... the AE was crap and is much better now...


orr i dont think the wideband is doing opposite because of the ae issue... car runs better with more AE... i havnt had a lot of time to get it perfect... maybe 1 quick tune a week... Also, i noticed the blms were 124 around 28gms/sec and in open loop it showed i beleive 14 a:f... so wouldnt that be correct?
I dont know, i just thought the narrowband was almost useless wot... i think im going to wait for the new regulator and then get the proper psi in the lines and proper constant then go from there... I still think its a fuel problem....

one quick question... would the rocker arms too loose or too tight cause a problem like this?

 

More AE, up to a point, always feels better. However, if you need to pass an IM240 emissions loop, won't happen with high levels of AE. Could always just run open loop and enjoy the power and not even be close to passing even a simple tail pipe sniffer.

If you think that your WB reported AFR of 20+ is correct, re-read post # 8. Not going to happen if the engine is still running let alone pulling. No-way, no-how, period.

Tuners need to realize that items such as WB O2 systems, NB O2 sensors, EGT sensors are just tools in the kit. They aren't the end all to be all. You still need to understand engine theory and tuning, and be able to look at plugs, and do sanity checks. And smell the exhaust, listen to the engine, feel the engine, it all adds up.

"Also, i noticed the blms were 124 around 28gms/sec and in open loop it showed i believe 14 a:f... so wouldn't that be correct?"

Is what correct? When in open loop there are no active corrections being made. The BLM of 124 if being used during non-PE mode, and ignored during PE. But this value was created from the last time the ECM was in closed loop, which was when?

RBob.

 

 

i just checked the fuel pressure and at idle with vaccum line connected its at 25psi, vaccum disconnected its at 29psi... during a full throttle acceleration with it taped to the hood scoop it showed 29/28 psi.... so bad regulator?

 

yeah, either the regulator is junk, or the fuel pump isn't flowing enough.

 

its a stock type fuel pump replaced about 3 years ago and it did fine with the TPI setup.. stock tune was good. no accel problems or anything... so im really thinking its the regulator... bad news though its on back hold

 

fuel pressure really should be closer to 43 psi, not 28. Can you get it to produce more pressure?

Does it bleed down fast after you shut down the car?


Also, any chance you can get 1 or 2 new spark plugs identical to the ones you have now, and put them on number 1 cylinder and maybe number 8 and do a WOT run for a quick few seconds and shut it down to coast to a stop. Then pop the plugs out and inspect them?

 

I guess a few things I would have to ask, Is the WB on the same bank as the NB O2? Do you have any exhaust leaks on the side of the WB? Generally that problem is worse at part throttle but not always.. If not on same bank you may have a lean or rich misfire happening, this will pump Unburned air through exhaust giving a false reading.. You need to do what Orr said, do a WOT pull, shut car of before letting off gas and pull a plug. I also think Rob would be correct, your car really would have serious issues at 20:1.. I also do not trust a narrowband one bit, my car initially was over 14:1 and NB read 820 ish.

 

As 87TA said, a misfire will give you a false reading.

 

the NB is in the drivers side header collector, the wb is just before the muffler exactly where the cats used to be.. Im afraid of full throttle anymore because of the lean issue and if you think about it its probly not quite that lean but darn close because when i did the calculation at 29psi it makes a 21lb injector a 17.1lb.. that from what i understand shouldnt be enough injector for lets say 275fwhp... as for the pressure dropping off it does not, it held steady pressure for 2 minutes yesterday before i decided to unhook the gauge


what would be the best way to diagnose a misfire? the engine does stutter a bit at idle and cruise but i figured that was due to the fact of 25-29 psi not being enough to cause the injectors to spray and instead cause more of a drip

 

fix your fuel delivery issue before hunting for misfire causes, they may be related.

 

You need a regulator.

 

As mentioned above, being to lean or rich will also cause a misfire. But if you have a bad wire or such can/will do it too.. get some pressure in that thing and see what happens.

 

i finaly received my regulator yesterday after more than a month of waiting i installed it, set pressure with vacuum off at 45 psi... had to take the guage i was borrowing back to the parts store but just from a free rev the pressure was dropping to low 30's with vac connected.. I wasnt able to do a wot run.. Anyway, im still getting the lean issue so my next project is the fuel pump

 

i have my new fuel pump in, the car responds a lot better. The strainer on the old one had a lot of gunk buildup and rust... Im assuming my fuel filter will be the same.

I am still getting the lean issue. I did however find the problem i beleive
My BRAND NEW exhaust has holes in the welds. Go figure. I am almost 100% positive this is the issue. Tomorrow i will arrange an appoointment to get it fixed.

 

exhaust leak was the problem. turns out im running 10.9 wot in most areas with the 22lb injectors at 45-45.5 psi