Printable View
Seeing some Bank 2 Bank stft error at idle seems to go away once I get driving.
This normally points to exhaust leak correct?
Car is 2001 Cobra with Comp Stage 2 cams and high compression build. No easily audible exhaust leak.
Overall cars runs decent just fighting surging idle and dashpot issues (stalling hot start wont stay idling etc...)
Tune and log attached
Attachment 94272Attachment 94273
If possible, have you tried swapping O2 sensors bank to bank and see if its just a sensor problem?
Seems to me like they are responding the same direction, just at different rates. One may be clogged up more than the other.
Switched them but of course datalogging for some reason tonight was impossible with hptuners. Getting at most 10 to 20 seconds of data than nothing for 1-2 mins. Gave up tonight I will try again tomorrow if I can datalog.
Also one thing i notice is if I start up and never touch the throttle it will run and idle all day no issues. The second i touch the throttle it will not idle anymore no matter what.
I did a throttle reset this weekend. Disconnected IAC and adjusted throttle stop till it barely idled at commanded. Turned off car adjusted TPS to read .97volts, cleared memory and reinstalled IAC. Seemed to idle a little better.
I am not sure if I need to mess with the ISC transfer function, dashpot, or idle airflow P/N.
Also for idle tuning we do not have ISC Duty cycle available on the EEC-V is there a way to calculate it from Idle Adapt STIT ?
The O2 sensor swap is a good first step.
Beyond that, it could be an exhaust leak showing false lean, a vacuum leak at the cylinder head showing a true lean, or an imbalanced bank of injectors.
Got the o2s swapped unfortunately could only get a cold start data-log before it stopped working again. See attached log. Attachment 94333
Looks to still have some bank to bank error but not so negative. I may try swapping injectors from side to side this weekend and see if the variance follows this will point me toward injectors.
They are new 39lb ford racing injectors. Wasn't there a rash of knock-off 39lb injectors going around?
Compression and leak down are good on the motor so do not think I have any mechanical issues. Might order me a smoke machine and check for vacuum leaks but it passed the idle with brake cleaner test with flying colors when checking for vacuum leaks.
Additionally, briefly speaking with the previous tuner of this car he tuned it with 02s turned off because according to him they weren't responding... I ohmed out the entire engine harness when I had the motor out.
Looking at the 02s they do not have the green wiring covers on them so probably not OEM parts should I go and put FORD 02s on the car?
Any other tips let me know.
No change to bank to bank error. I have smoked intake no vacuum leaks besides at IAC which I believe is by design correct? Also swapped injectors between sides and saw no change.
Also I noticed adding 10% fuel made no change to the swing either direction. Commanded EQ was the same and STFT didn't change nor did wideband avg. I did notice much more swing in the wideband 02/lambda readings.
I will purchase some Motorcraft 02s and give that a try and see if that will fix it.
Sounds like you have an exhaust leak somewhere between the header flange and O2 sensor on whatever bank shows more lean.
speaking of that it is always bank 2 drivers side showing lean. Same side EGR valve is on, I noticed when smoking the car I saw some leakage at the egr though I thought that was normal. Reading some info says I should not have any leakage at the egr. I will possibly replace the egr and see if that fixes the issue. I do not have egr disabled in the tune either.
You could start by disabling EGR in the tune, as a test.
did disable egr in tune no change to stft mismatch.
Here is a log of it drivingAttachment 94446
do notice i get random misfire counts on some logs but not others. Car drives fantastic no stutter miss or issues except stalling when coming to stop and of course the stft bank to bank errors.