Spamby
Meat Product Toy
No. I didn't, actually. I wanted to see it make the changes after the fixes.... errr am I being dense and should've reset? Am I going to face palm now ?
A/F Correction
- Thread starter welaish
- Start date
No. I didn't, actually. I wanted to see it make the changes after the fixes.... errr am I being dense and should've reset? Am I going to face palm now ?
HolyCrapItsFast
Drinks beer!
After any change, I believe it is better to reset the ECU. It takes longer for learned data to change if it is already populated and it is harder to see the trend. You can better see any changes in correction from a reset point in that it starts from Zero, and if there is still a significant problem, it can be clearly seen as learned data is populated and a trend is developed. :tup:
Spamby
Meat Product Toy
I'll do so this evening when I leave work.
Spamby
Meat Product Toy
[MENTION=9]HolyCrapItsFast[/MENTION]
I reset the ecu before I left work. I evidently didn't hit start to log so I didn't capture one. However, I did notice LTFT was increasing on the way home. By the end of the 10 mile drive, my fuel trim was showing 10.8 at cruise and was back hitting 8.7 at idle, positive.
I imagine that by the time I return to work in the morning my fuel trims will be back to +18 while cruising.
Whats a little surprising is that fuel trims at idle used to be around +2 to +3. But here lately have increased to the 8.7.
Also, I am very confident that there are no leaks now.
I dunno if weather effects them much? I'm sure it does but to what degree?
I reset the ecu before I left work. I evidently didn't hit start to log so I didn't capture one. However, I did notice LTFT was increasing on the way home. By the end of the 10 mile drive, my fuel trim was showing 10.8 at cruise and was back hitting 8.7 at idle, positive.
I imagine that by the time I return to work in the morning my fuel trims will be back to +18 while cruising.
Whats a little surprising is that fuel trims at idle used to be around +2 to +3. But here lately have increased to the 8.7.
Also, I am very confident that there are no leaks now.
I dunno if weather effects them much? I'm sure it does but to what degree?
Spamby
Meat Product Toy
[MENTION=4684]welaish[/MENTION]
Yep. No stumble but that rpm range is smack at cruising speed on highway or streets. That's where the fuel trim is the highest and that rpm is where most of the time is spent. Switching gears has no effect so long as it's in the same rpm range.
Spamby
Meat Product Toy
If mine is fueling, it's likely my ID1000's are exasperating the issue. Just a thought.
HolyCrapItsFast
Drinks beer!
Okay, The key is to identify any and all issues first before you go any further with new hardware or tuning...
The next step is to determine if the O2 sensor is working properly. Do you have a wide band installed? If so then compare your A/F Sensor Ratio #1 with the wide band reading. They should be very close. If they are not close then confirm a bad O2 sensor by forcing the car into open loop by unplugging it completely and then see what your wide band afr's are. They should be close to normal.
If all is good then I would suggest cleaning the MAF sensor and see if that improves. Also clean you air cleaner.
If that does nothing then we can basically rule out any mechanical issue and we now have to look at the tune. Who tuned the car if you don't mind me asking, and when was it tuned? 18% seems a bit high to me and based on that alone I would automatically suggest a leak, but it is possible to make corrections and repairs over time and throw off your tune that much. If you say there are no leaks then I believe you, but it is critical, to a good tune, that there not be any.
Last edited:
Spamby
Meat Product Toy
Definitely not buying anything unless it's broken.
Not tuning cause that would require a 4 hour drive. Map is locked.
Don't have a wide band.
I've swapped front sensors. There is no change one vs. the other. If that helps?
I'll try the MAF cleaning. It has been awhile since. But I've swapped those, too with no change.
I will also clean the filter.
Cobb tuned in Plano, TX
Tuned 9-2012
The only thing added was the Moroso AOS since the tune.
Unless it's a shit tune which it could be. Possible I had a boost leak when I brought it in for the tune and they didn't catch it or "worked" around it. Since then may have fixed it but it's tuned for air that's not now there? Plausible?
Or it's the FPR? Diaphragm blew?
Or fuel pump? Oring funked up? Filter clogged?
Last edited:
Spamby
Meat Product Toy
Fuel trims are down a bit at idle. Now at seven positive.
Fuel trim has seemed to settle at 16.4 positive while cruising. Again in that sweet spot of 3k ish rpm. Go beyond that in either direction she goes down.
Stopped in a parking lot and free revving to that 3k rpm spot, fuel trims go back to 16.4 positive. Again, over or under that general rpm and she settles down.
I'll try to hammer out a timeline of all the instances over the last few years and measures taken. [MENTION=9]HolyCrapItsFast[/MENTION], we've probably been discussing this very issue for quite some time, on and off.
I dunno if the AOS has anything to do with it, it could but since it's not a VTA setup and us all plumbed back as a closed system, I'm leery of punting the finger at it.
Fuel trim has seemed to settle at 16.4 positive while cruising. Again in that sweet spot of 3k ish rpm. Go beyond that in either direction she goes down.
Stopped in a parking lot and free revving to that 3k rpm spot, fuel trims go back to 16.4 positive. Again, over or under that general rpm and she settles down.
I'll try to hammer out a timeline of all the instances over the last few years and measures taken. [MENTION=9]HolyCrapItsFast[/MENTION], we've probably been discussing this very issue for quite some time, on and off.
I dunno if the AOS has anything to do with it, it could but since it's not a VTA setup and us all plumbed back as a closed system, I'm leery of punting the finger at it.
HolyCrapItsFast
Drinks beer!
I agree about the AOS. If you ultimately can't find anything wrong mechanically then it is likely the tune and likely due to the fact that you fixed stuff since then.
You do have another choice and that is to let me tune it. The only thing you would have to do is install a wide band. :tup:
You do have another choice and that is to let me tune it. The only thing you would have to do is install a wide band. :tup:
I have the exact symptoms on idle as well when you apply throttle to. 3k rpm. [MENTION=9]HolyCrapItsFast[/MENTION] but why the tune is changing. The car was running fine and suddenly this symptoms appeared. I know you can change maf Scaling and adjust. But that won't be a solution it is just workaround.
Spamby
Meat Product Toy
Yes. I've definitely considered your tuning. Too many positives and the mist is in not locked under Cobb's damn map.
I'd have to weld in a bung but it's easily doable. Got a welder for that.
Let me chase down the fuel system first before we go any further.
HolyCrapItsFast
Drinks beer!
In spamby's case it could be the tune now because he made some repairs since, and the tune is off as a result. It could also be complicated by the possibility of a bad tune or one that was not well thought out for changes in environment, I.E. weather, temperature, humidity, atmosphere and so on. So much can effect the tune. Also keep in mind that the engine dynamics are changing over time as things wear and or settle in. Your engine is not the same today as when you first bought it.
In your case it sounds like poor MAF calibration because A.) you did everything to trouble shoot and B.) If there is a leak or a mechanical issue, it is usually observed through out the entire RPM range and yours is in a very specific spot.
The tune is the last thing I will touch because, as you suggest, you may be just throwing a bandaid at it otherwise and negating the real problems. Unfortunately their is only so much you can troubleshoot before you give in and suggest a tune.
The other thing that complicates things are the Load Comp tables themselves. I have observed their effect to be more susceptible to changes in environment and if you go back to the stock GD Load Comp tables, you will see that there is no Load Compensation for anything other than idle and off idle regions and so the OEM is not compensating for much of anything because it just works as expected. When there was a problem or someone changes something in the intake plenum thereby changing the flow characteristics, it was solved or compensated for by applying Load Comps as needed. If you then take a look at the GR and GV, you will see massive compensation in the region between 2200 and 3200 rpm. This is telling me that they knew of this issue because of some design change and then implemented this in load comps. Also the new tables have much more definition and resolution than the GD. Again why? So when a problem manifests itself in the GR and the GV, you adjust your load comp because they are already applied. Regardless there is a significant relationship between Load Comps and MAF calibration and I have always insisted that the MAF be properly calibrated first before any load compensation is made. And I mean meticulously, anally, to the point of rediculously maintained. As such I always zero out my Load Comp tables before I attempt to calibrate the MAF. So I essentially throw out the factory compensation and define my own as needed.
It works in almost every case and I would be interested to see what is revealed if I start tuning someones car that has this problem. As such when I begin tuning, I always start with a customized base tune. I call this my ZERO point because I zero out some key compensations first. This is how I am able to determine what needs adjusting and it is also where you start to see all of the cars real problems and short-comings. You start to get a feel for what the OEM is compensating for.
Last edited:
Spamby
Meat Product Toy
HolyCrapItsFast
Drinks beer!
Sounds right to me :tup:
Similar threads
