What does the ecu need to see to go into Closed Loop Cruise mode???

[driftin8ez]

I just got a narrow band O2 sensor so i can loosely monitor my afr's. Well i went on a highway cruise today and noticed my afr gauge wasn't doing the disco as it should be while cruising. It just stays in the rich range reading about 12 or 13/1 afr. So what does the ecu need to see to go into closed loop? I don't have my fifth gear switch hooked up could that be it?

[capowered240]

The ect (engine coolant temp sensor).

[driftin8ez]

Ya this is about the third (cts) i've put in the thing. None of which where new. LOL. I'll go pick up a new one tom. and see how it does. So what are the conditions the ecu needs to see for it to go closed loop. Do i need the 5th gear switch wired up too?

[capowered240]

Do i need the 5th gear switch wired up too?

No.
Modified by capowered240 at 6:13 AM 7/16/2007

[float_6969]

It's usually based on load and RPM. If it's w/in a certain rpm range (mabye 1750-4K?) and within a certain load range (maybe .75v-3.5v from the MAFS) then it will alter the fuel based on the input from the O2 sensor, otherwise, it ignores the O2 sensor and goes off of the internal fuel maps.

I made those numbers up to just give an example.

[driftin8ez]

Ya i would think that at about 3500rpm in 5th gear running about 15-17in HG vacuum would be the perfect condition for closed loop operation. However my afr gauge is reading about 12.5-13/1 A/F which is far from ideal cruising ratio. I'm going to put in a brand new cts tom and give it a whirl but i think my problem is somewhere else. I have a re flashed eprom in my ecu just for an N60 maf and readjusted fueling/timing for 12-13 psi. That shouldn't affect closed loop should it? Like basically disable it.

[BEST1TUNING.COM]

Originaly from the factory the ECU contains a section in its fuel mapping that has values in binary that are different from others. Values in this specific section contains a flag bit wich tells the ECU to look at o2 sensor voltage and correct fuel. Often times in a ROM editor this section can be seen as having larger values than most in the fuel table. This is because it contains the extra flag bit. Removing this bit from the raw binary value in the actual rom or subtracting a specific number from the value in the fuel map will give you the actual fuel value and inserting this value into the map will turn off o2 sensor correction.

Since you are corrected for an N60 maf, your correction could be off depending on how good your ROM supplier is at getting your TP (load) values correct for that MAF) If they are way off, it is possible you are not even reading from the o2 values in the map, or they have turned them off and u need to lean out, or possibly your TP or original "theoretical pulsewidth" within the corrected maps are too long. If you have not recirculated your BOV and it is slightly open at vacuum/cruising, this will also cause your lean condition. There are fixes...but those should be up to your ROM/tuner to know and apply.

I believe I was going to do a ROM for you but dont believe I did. If I infact did please contact me with any issues.

[driftin8ez]

Originaly from the factory the ECU contains a section in its fuel mapping that has values in binary that are different from others. Values in this specific section contains a flag bit wich tells the ECU to look at o2 sensor voltage and correct fuel. Often times in a ROM editor this section can be seen as having larger values than most in the fuel table. This is because it contains the extra flag bit. Removing this bit from the raw binary value in the actual rom or subtracting a specific number from the value in the fuel map will give you the actual fuel value and inserting this value into the map will turn off o2 sensor correction.

Since you are corrected for an N60 maf, your correction could be off depending on how good your ROM supplier is at getting your TP (load) values correct for that MAF) If they are way off, it is possible you are not even reading from the o2 values in the map, or they have turned them off and u need to lean out, or possibly your TP or original "theoretical pulsewidth" within the corrected maps are too long. If you have not recirculated your BOV and it is slightly open at vacuum/cruising, this will also cause your lean condition. There are fixes...but those should be up to your ROM/tuner to know and apply.

I believe I was going to do a ROM for you but dont believe I did. If I infact did please contact me with any issues.

I eventually decided to buy a willem burner and tune the damn thing myself. All i changed was the k value to hex 012A for the N60 Maf and updated the vq map to read 64pt's instead of 54 and injected the correct vq map for my maf. The tp scale and fuel maps all show the bit flags being the same as stock. In live edit they are shown as a blue section in the lower rpm/lower tp scale range. All i did was change the fueling and timing in the upper ranges. So i think my bin file should be correct in that sense.

[BEST1TUNING.COM]

Oh great! Thats awesome you were able to get it working yourself. How is your BOV set up?

[driftin8ez]

Oh ya i forgot to mention that. My bov is from an the stock one from an audi TT and it is correctly recirculated back into tghe intake pipe in between the turbo and the maf. Also i have the pcv system setup like stock. I just got a brand new cts and NTK o2 sensor and still no dice?? I was on the ztechz forum and they suggested i lower my k value until my idle afr's are closer to 14.7 but i dont know if that will drop me back into close loop mode or just lean my car out a little.

[driftin8ez]

Ok i just lowered my k value about 40 decimal to 259 or 0103 hex. My afr's are alot closer to where they are supposed to be and that is about as low as i'm comfortable going only working with a narrowband 02. Still no dice with the closed loop disco strobe yet????

[BEST1TUNING.COM]

I will be honest and say that you might see completely different results with wideband readings. I wouldnt try to get precise tuning from a narrowband.

[driftin8ez]

I'm going to raise the k value back up to 270 dec just to be safe and thats what im going to wind up buying next... How sensative in the k value? When im trying to tune in my afr's should i lower it about 10 dec. at a time?

[BEST1TUNING.COM]

Do it in 2% increments. So multiply the dec K value by .97 to lean or 1.02 to enrich and then convert back to hex. increase the % untill you get the desired amount of enrihment or lean. Then keep multiplying by this amount untill you get close to your desired AFR and then adjust in the maps.

[driftin8ez]

ok i'll save this thread for when i get my wide band and i'll refer back to it. Howdever im still stuck without close loop mode???

[BEST1TUNING.COM]

Actually you can still be in closed loop, its just the ECU cant get you a 14.7 AFR. Even though you have done the baisic corrections for the MAF there will still be some fine adjustments to be made to get everything diled in.

[driftin8ez]

ok cool... Ill get everything dialed in when i get my wideband.

[Liquid_Neon]

Hey... i dunno if this is useful anymore.. but i tested my loops with my narrow band. under about 15% throttle (give or take) and RIGHT up until 4000rpm my gauge stays bouncing. the second it crosses 4K, it goes to open and goes rich.

Just thoguht id share that somebody was 100% correct... someone said those numbers in a good guess.

[driftin8ez]

was your ecu totally stock or was it chipped?

[driftin8ez]

Just a quick update. I got an hks evc III boost controller and swapped out my old ghetto wastegate line that I turned into swiss cheese to get my boost where I wanted it. Anyhow now my car runs a lot better. Took it on the highway for a gas mileage cruise and pulled about 90 miles from a 1/4 tank so i should be good for around 360-400ish miles to the tank which is acceptable. It also seems as if im in closed loop during cruise and my afr's read ok during wot. For anyone wondering i have my kvalue set at 270dec right now which seemed to get me right where i wanted afr wise accroding to my narrowband. Im going to pull my plugs tom. and make sure they are a nice chalky brown to confirm my afr's are close to spec.

Conclusion: I attribute my swiss cheese vacuum leak of a waste gate line for me not getting good mileage and no closed loop.