wont stay in cosed loop in cruise

[gto reynolds]

hey i need a little help i have a 06 gto 408 stroker automatic the car will not stay in closed loop going down the road it will at idle and durring accel but not on cruise but if i blip the throttle it will go back into closed loop for a intermittant amount of time then it flips back to open loop just havnt been able to pinpoint the problem the car has lt headers but o2 s seem to b switching rapidly before it does so i have a hard time believing that they r to cold any clues

[rally1]

Hi there, can you post a copy of your tune? Are you running a custom operating system?

[gto reynolds]

its not a custom operating system and here is the tune

[ssvolvo]

Can you list your mods?

Injector size and cam specs?

That thing must suck some gas eh?

Do you have a wide band installed?

[tblu92]

Hi---I took a look at your log--seems like it runs fine at around 57-60 KPA then suddenly the KPA drops to around 37-47--and it goes into OL-- Eventually the KPA will go back up again and it will go back into CL--It runs in OL when in cat protection mode-but you have that disabled--and the other protection stuff may also make it run in OL but that all looks OK too--I did notice on your tune that you messed around with the DFCO settings--When DFCO is activated it will go into OL--Could be that this is the culprit ?? Try disabling the DFCO entirely--I played around with these setings quite a bit in trying to get better mileage--but all that happened was it would go on and off all the time and was very annoying--Eventually i gave up and returned everthing bak to stock --But i remember--when it was activated it was in open Loop--

[SSpdDmon]

I didn't look at the tune - but is lean cruise activated? Any time the car is not commanding stoich (i.e. DFCO, WOT, lean cruise), the car will not run in closed loop.

[gto reynolds]

i do have a wide band i just dont log them at the same time i use innovate software for that it seams more accurate i have 60 lb inj headers ported and polishished heads 11.4 compression stock intake cam specs r 232 250 622 634lift on a 116 ls afr 12.8 wot 14.7 idle and 14.7 closed loop cruise 16 to 18 in open loop cruise but if i goose the gas it goes back into closed loop ive been allm over dfco suspecting that was the culprit but to no avail hence the post it also has a 4l60 trans and a vigillate 3600 stall 11.62 all motor 10.29 on a 175 2 stage wet and dry shot on a proggesive controller and gets about 18 miles to the gallon

[tblu92]

All that is fine but all the mods you have don't really explain the O/L-C/L problem you're having with the ECM--It seems you have a purpose bulit race type engine and I can't quite understand why the need for DFCO or Lean Cruise at all ?????--If your tuner purposely tuned it to run that way for better mileage--then you may be stuck with it that way-- As SSPDOM says if you are going into "lean cruise" then it will drop into open loop----gonna be tough to sort out without having the car and a logger to view---To me you are a great candidate for a Speed density tune--Huge cam--lots of compression--big cubic inches--Aren't you at the end of your MAF scale ??

[ssvolvo]

Was this tuned by a tuner or you?

Reason I ask is that some of the changes from that GTO O.S. you are running are wierd.
I run the same OS in 2 vehicles I drive. If it was up to me I would change about half those tables back to stock and start over with the VE, but first be sure the injector flow base is correct.
Why have you changed B5120, B5121?
Put all of the DFCO back to stock GTO. It works great, cutting the fuel within a second or two of letting off the gas.
Put the P.E. all back to stock then change B0156 to 8% and set B3618 as wanted.
Do you still have the stock file?
Has the thing been on the dyno? Just being curious. I have an 06 M6 GTO all stock (WIFEY) it won't get out of it's own way! Very heavy.
Don't be afraid to use B0148 for high load open loop as this table works well also.
Holler if you need the stock file. That OS was an upgrade for ETC issues from GM. It is not in the BIN suppository.

Keep us posted, John

[gto reynolds]

hey i tuned this thing myself and messed around with alot of settings to figure this problem out so im sure so parts of the tune look out of wack i usually go to extremes to c changes easily it works for me i reverted back to stock dfco and no change then noticed that my maf read less air the caculated maf so after cking it out it was 15% down across the board descreened maf recalibrated it redid ve table fixed!!!finally i guess the two tables not correlating wiged the pcm and forced open loop

[gto reynolds]

hey ssvolvo all i can say is cam cam cam my first setup was a thunder ls2 cheater cam and everything else stock except nitto drs and a stalll car ran 12.50s with no difference in driveabilty and on the spray a 11.26 on a 150 shot on proggressive con.