I was wondering if this is bad to do? I just noticed that the shop that tuned my car got rid of both my O2 sensors.
Also with my tune I can't go over 80 mph in 5th gear. It goes pig rich and falls on its face. Even if I shift from 4th to 5th and I am going faster than 80 mph I still cant accelerate. I can only maintain that speed and even then it is still really rich in the 10s.
Thank you.
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
I think the shop screwed you....go back and get your O2 sensors back yo!!! But yes it is possible, IF ITS DONE RIGHT.
Well the car runs a great lean cruise like this that is for sure. I just have a bunch of holes in the fuel maps. I am thinking that is because of the Alpha-N. I was also thinking that if I enable open loop and put the bank one O2 back in that I could then change the PE enable to a higher rpms that the fuel trims that the computer makes will help fill those holes. Then Perhaps I will get use of my 5th gear again.
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
since you are referring to Alpha-N i assume your using the stock map sensor correct?
stock map sensor has nothing to do with fuel on an eco jbody.
disabling open loop? no o2 sensors? closed loop is when the car looks for the o2 sensors, open loop is when it ignores them and goes to the maps... I think you mean disable closed loop.
you don't want to do either.
running excessively rich will cause lots of wear on head components and lots of carbon build up.
take your car to a different shop. the primary O2 sensors should NEVER be removed.
yes stock map sensor. Whenever shifted's ECU comes available I am switching to my 3 bar.
So what's on your mind?
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
Pj is correct I went off thinking ld9 options. But yea def go to a different shop
Ok so last night. I moved my AEM wide band to the post cat spot. (I have no cat though). Yes those dumb asses had my wide band right after the turbo. I am lucky I haven't burnt out the Bosch sensor.
Then I put in my bank 1 narrow band back in to where the AEM used to be. After I replace the Rear main Seal for the 3rd time (that shop did it twice and it is still leaking) I will use my hpt to lower the enable closed loop temps back down to operating temps.
Then I have a buddy of mine that is going to help me tune my car a little bit more to get the tune just right so I can get my 5th gear back. I think that I may also go back to the FMU if I end up needing to do so. Right now i have a adjustable fuel pressure regulator. I think it would help if I had something that uses boost and increases the fuel pressure.
The thing that seems to be murdering my tune is that the high RPM table TPS % jumps from 50% to 100%. I need at least a 65% in there. So after spending at least a full minute cursing GM for this Alpha-N operating system I decided that a standalone is in order. Shifted get well soon.
Not to worry I will never go back to that shop.
Any ideas that you guys have would be greatly appreciated.
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
Hey man its steve that emailed you about hp tuners help awhile back. I copied your tune and had the most probs out of it. I dont no why but it would even stay running. It just cranked and then died. I reflashed back to stock and turned all my i forget what its called but the 2 tables under high rpm ( think its called double fire or something) changed all those from 25% throttle up to way high numbers. I have my 100 % throtlle on like 160 and the less throttle the less number. I dont know exjactly how to use hp tuners rite because i only have standered but thats how i did it. I run pretty rich when i hit the gas but then boost comes up and it hold right at 11 to 12. Really rich tho when i first hit the gas. I have no probs with my 5th gear. I did however keep ur spark maps beacause i didn't want to blow anything up running 15 psi. Just wanted to let you know how i was doing! hope all is well and you get your car running good.
Steve
They got rid of your o2 sensors? WTF You should never even drive the car without an 02 sensor. The entire purpose of the o2 sensors is to tell the engine how rich or lean you are, without that it has no idea whats going on, its like taking out your eyeballs and trying to hit a baseball
The wideband should be 18inches from the cylinder head for optimal readings, if your using an fmu id suggest a small ratio one when being used with HPT like a 4:1 or a 6:1
Alpha N is sometimes a pain but its not impossible to work with, pity we cant tune you over teh interweb
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
The FMU that i have available to me is the BEGI that came with the HAHN stage 2 kit. I took it out when I went to the 750cc RC eng injectors. If i am not mistaken that FMU is a 5 to 1.
I really wish I could get tuned over the interweb. Well what I would really like is to have every one send me their tunes so I can see how they did it. There so much wrong with this tune that I don't know where to start.
Well scratch that I want to start with getting my idle down from 1100 rpm to close to stock. Then I want to work on the DFCO table since I am way too lean. The WBO2 cant even read it since it is so high.
This weekend will be all tuning once I can figure out what is draining this brand new battery.
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
Rodimus Prime wrote:They got rid of your o2 sensors? WTF You should never even drive the car without an 02 sensor. The entire purpose of the o2 sensors is to tell the engine how rich or lean you are, without that it has no idea whats going on, its like taking out your eyeballs and trying to hit a baseball
The wideband should be 18inches from the cylinder head for optimal readings, if your using an fmu id suggest a small ratio one when being used with HPT like a 4:1 or a 6:1
There is absolutely no issue with running a car without O2s at all... if everything else is right.
The factory O2s do not ever tell how rich/lean you are. They can only tell the PCM if you are above/below 14.7.
When I calibrate a car, I always do the whole job with no PCM feedback so that I don't end up chasing corrections instead of actual errors.
When I am done, there is no reason at all to need to run in closed loop until long term mileage has altered the breathing of the engine. But this only applies to one specific engine in one specific configuration in one specific car.
Now, it has to be taken into consideration that I can spend weeks doing the whole calibration and getting it all right to run that way. Its definitely not possible to do in an hour or two on a dyno.
To answer the question as it was posed. No its not ever possible to disable
open loop. There are many normal circumstances where an O2 can't work.
To answer the question as I think it was meant to be asked, yes it is possible to disable closed loop and there are real advantages to doing so in some instances (more radical engines).
But the real odds are that the shop you went to did what they did for really poor reasons and should never have done it.
sig not found
protomec wrote:Rodimus Prime wrote:They got rid of your o2 sensors? WTF You should never even drive the car without an 02 sensor. The entire purpose of the o2 sensors is to tell the engine how rich or lean you are, without that it has no idea whats going on, its like taking out your eyeballs and trying to hit a baseball
The wideband should be 18inches from the cylinder head for optimal readings, if your using an fmu id suggest a small ratio one when being used with HPT like a 4:1 or a 6:1
There is absolutely no issue with running a car without O2s at all... if everything else is right.
The factory O2s do not ever tell how rich/lean you are. They can only tell the PCM if you are above/below 14.7.
When I calibrate a car, I always do the whole job with no PCM feedback so that I don't end up chasing corrections instead of actual errors.
When I am done, there is no reason at all to need to run in closed loop until long term mileage has altered the breathing of the engine. But this only applies to one specific engine in one specific configuration in one specific car.
Now, it has to be taken into consideration that I can spend weeks doing the whole calibration and getting it all right to run that way. Its definitely not possible to do in an hour or two on a dyno.
To answer the question as it was posed. No its not ever possible to disable open loop. There are many normal circumstances where an O2 can't work.
To answer the question as I think it was meant to be asked, yes it is possible to disable closed loop and there are real advantages to doing so in some instances (more radical engines).
But the real odds are that the shop you went to did what they did for really poor reasons and should never have done it.
So im having conflicting info in my head.... If i were to run a car in open loop during tuning it will follow the maps... no matter what the computer will not pull or add fuel? If thats the case i could have save myself LOTS of dicking around on brians car.
whenever your WOT your already in open loop, open loop cannot be disabled but closed loop can be
the only thing that happens when closed loop is disabled is that your gas mileage will be @!#$
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
well your gas mileage will not suck if you tune the low rpm (single and double fire) tables to be leaner than 14.7. That is how mine is at the moment. When the car is just cruising I am around between 15 and 17 for AFR. Then you lower your delay rpm to 0 so it will use the maps sooner and more often.
By looking at what I have in HPT that seems to be the safest way to do it. You will still allow the computer to enter closed loop at idle.
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
Rodimus Prime wrote:whenever your WOT your already in open loop, open loop cannot be disabled but closed loop can be
the only thing that happens when closed loop is disabled is that your gas mileage will be @!#$
No it won't.
You are confusing a PCM response to a failed O2 with running in open loop.
When the O2 fails, the PCM runs richer "just to be safe".
But if your VE tables are perfect, then so will be the way the car runs in open loop.
Some early older systems wouldn't enter closed loop for up to 20-30 minutes after start.
New cars like your cobalt will enter and leave closed loop regularly as you cruise steadily down the highway as a way to control cat temp.
Running open loop only can really help in a car with big cams because they tend to like to run richer overall, especially at idle. Most of the J's I've seen that "lope" at idle really don't. They are just running too lean (14.7) for the cam to idle smoothly.
Wrench Monkey wrote:So im having conflicting info in my head.... If i were to run a car in open loop during tuning it will follow the maps... no matter what the computer will not pull or add fuel? If thats the case i could have save myself LOTS of dicking around on brians car.
Yep.
Back to the post'er of this topic...
I have to quess that whoever tuned your car did not spend the time needed to do it right. So your car probably isn't "right" as it sits now. O2 sensors add a crutch to help a less than optimal tune and could probably help you more than not.
sig not found
Yeah this tune that I am running needs some serious help. It looks like once I get the car to stop leaking tranny fluid and find out why the battery keeps going dead I will attack the tuning. How sad is that. I am dealing with all these kinds of problems after getting my car back form a performance shop.
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
Quote:
protomec wrote:
No it won't.
You are confusing a PCM response to a failed O2 with running in open loop.
When the O2 fails, the PCM runs richer "just to be safe".
Todd is right. I had that same issue with my Z when I tried to use my Innovate wideband to simulate the narrowband output. The PCM failed the o2 and she started running pig rich. I was running about 11.5 to 12 @ WOT, and the PCM started adding fuel and it shot down to 9.5 @ WOT. I had to reinstall the stock o2 and reflash the computer to fix it
Jason
99 Z24 Supercharged
157hp/171tq - NA
LD9 for Life
