rob-2 Posted February 17, 2014 Share Posted February 17, 2014 Can you post a Learning View? And by the way when I reset the ECU and took the car out for a drive to see if replacing the O2 sensor took care of the issue, I was registering -6 degrees of knock correction just dragging around town. It went completely away once the ECU started enriching to adjust for whatever is causing it to do so. So the car was definitely running leaner than it was supposed to which seems to have led to some very low load repeated knock, about 4 events. I'll try to do this in the coming day or two That's a lot of knock correction. Typically after 4-5 degree it's pointing to a much bigger problem. Are you logging roughness on the cyls? Link to comment Share on other sites More sharing options...
fishbone Posted February 18, 2014 Share Posted February 18, 2014 Yes. No roughness. New development. Watched the AP and AF Learning 1A went up from 9 to 12 while just driving around. The one factor that makes it go up is sitting at red lights. If I put the car in Park, it settles back down as it idles more. So if I hold the brakes, correction keeps climbing. I bought a can of carb cleaner and I will try to test for leaks when I have a chance. I don't want to do it on a hot engine bay Link to comment Share on other sites More sharing options...
fishbone Posted February 19, 2014 Share Posted February 19, 2014 Looks like mine may be a tuning issue? A/F Correction still all over the board, A/F Learning A is inconsistent as well, depending on how much time the car spends at idle out of gear. Checked all vacuum lines, no evidence of leaks. Had a smoke test done, nothing. The only thing I have not done yet is pressurize the intake. Vacuum at idle with car in Park reads about -9PSI at 600ft elevation, I think that is normal, is it not? http://legacygt.com/forums/showthread.php/stumble-cruise-control-221051.html Link to comment Share on other sites More sharing options...
fishbone Posted February 20, 2014 Share Posted February 20, 2014 So I found this on the RR forums. I thought the rear O2 sensor is for measuring cat efficiency only? http://www.romraider.com/forum/viewtopic.php?f=15&t=3588 Could it be the culprit? How can it be determined short of replacing it? Link to comment Share on other sites More sharing options...
rhino6303 Posted February 20, 2014 Share Posted February 20, 2014 The rear o2 on 05+ (or 32 bit ecu) vehicles is used for fueling. This is why we can't just use the spark plug defouler on the rear o2 sensor for a cat inefficiency code. You could try using only open loop fueling and see if it improves. Method found here. Alternatively you can zero out the CL target comp tables at and near idle and your AFR should be extremely close to 14.7. Method found here. Here is what my CL target comp table is set at and my idle is very close to stoich instead of rich. Link to comment Share on other sites More sharing options...
fishbone Posted February 25, 2014 Share Posted February 25, 2014 I'm assuming both these alternatives are recommended as a temporary measure. I'm going to try open loop and see what happens. Link to comment Share on other sites More sharing options...
fishbone Posted March 6, 2014 Share Posted March 6, 2014 I've disabled closed loop an the cruise stumble so far seems to have been fixed. I only got a chance to use it for about a mile at 50mph but it is completely smooth. So where do I go from here? Does this rule out an air leak then? Link to comment Share on other sites More sharing options...
firehawk618 Posted March 7, 2014 Author Share Posted March 7, 2014 I've disabled closed loop an the cruise stumble so far seems to have been fixed. I only got a chance to use it for about a mile at 50mph but it is completely smooth. So where do I go from here? Does this rule out an air leak then? Hmm good info. I'll be curious if after a few days of no CL you still are smooth.... 10' CTS-V, A6, Airraid, 2.4 upper, ID850's, self tuned. SOLD:06' LGT Wagon. BNR16G, Catless UP, DOWN, Hexmods VB, Hexmods diff bushings, BIG TMIC. Best 0-60: 4.651 by AP 1/4= 13.678@100.73 mph, 1.945 60', Automatic transmission. Link to comment Share on other sites More sharing options...
fishbone Posted March 7, 2014 Share Posted March 7, 2014 Correction and follow-up. Issue is still there, but has become so subtle that it is almost not noticeable. The stumble has become an oscillation, like a novice driver struggling with keeping steady speed. Car increases throttle by 5% for a second, then backs off, rinse and repeat. The only thing I can see at this point to do is pressurize the intake to be 100000% there is no leak. I think so far my plan is that, unless anyone else suggests something else or I think of anything else, to wait until pumps here switch to summer gas. Last time I pulled a LV and used cruise was last year in May and my fuel trims looked just about perfect. I have not touched the car between then an now other than an oil change. Link to comment Share on other sites More sharing options...
evil03mustang Posted March 8, 2014 Share Posted March 8, 2014 unless anyone else suggests something else or I think of anything else, to wait until pumps here switch to summer gas. http://pure-gas.org/index.jsp?stateprov=TX Go get you some no-E. I wish I could find 93 no-E around here. :-( Link to comment Share on other sites More sharing options...
fishbone Posted March 8, 2014 Share Posted March 8, 2014 Closest one is 45 minutes away Link to comment Share on other sites More sharing options...
evil03mustang Posted March 9, 2014 Share Posted March 9, 2014 Closest one is 45 minutes away That's nothing. Go get you some of that. Link to comment Share on other sites More sharing options...
rob-2 Posted March 9, 2014 Share Posted March 9, 2014 I've determined mine is not actually a 'problem' My issue is the low load, few PSI part throttle profile of this H4 motor. I can feel the same profile while idling and between 1500-2500 rpm under medium throttle with small boost I feel that 'cycle' again. Link to comment Share on other sites More sharing options...
fishbone Posted March 9, 2014 Share Posted March 9, 2014 Do you feel it all the time or just in the winter? Link to comment Share on other sites More sharing options...
rob-2 Posted March 9, 2014 Share Posted March 9, 2014 Do you feel it all the time or just in the winter? All the time season wise. Most noticeable on slight climbs. Link to comment Share on other sites More sharing options...
evil03mustang Posted March 10, 2014 Share Posted March 10, 2014 I wish I had 92oct or better no-eth fuel within 45 minutes. It's a loooooong drive up to Warren, PA. Link to comment Share on other sites More sharing options...
SATSFYD Posted March 14, 2014 Share Posted March 14, 2014 Taking notes... **There are two types of people in the world, those who build horsepower and those who buy it. Which one are you? Link to comment Share on other sites More sharing options...
SATSFYD Posted March 14, 2014 Share Posted March 14, 2014 have you thoroughly inspected your turbo inlet? as i stated i have been having pretty much identical problems and found the other day that i had a small tear in my inlet right at the turbo. ordered a new one and went to replace it and found that it was not even clamped down on the turbo, oil impregnated and soft as could be, and the tear that i could see!!!! how my car was running at all is a mystery to me, but im hoping that now it will run a good bit better. lol. Did you take pictures? If so please post them. **There are two types of people in the world, those who build horsepower and those who buy it. Which one are you? Link to comment Share on other sites More sharing options...
SATSFYD Posted March 14, 2014 Share Posted March 14, 2014 I cleaned my MAF and the surge is less noticeable now... but would like to make it go completely away. My GT has 83,000 mile with a gutted uppipe and a AP stage 1 tune. I did not notice the surge at HWY speeds with cruise until about three weeks ago when I flashed my ECU with the AP stage 1. **There are two types of people in the world, those who build horsepower and those who buy it. Which one are you? Link to comment Share on other sites More sharing options...
firehawk618 Posted March 15, 2014 Author Share Posted March 15, 2014 About the only sensor I haven't replaced yet is the Cam sensor, that's next on my list. What I've done is buy cheap sensors. MAF, Crank position sensor and Cam position sensor. My logic is even a crappy one will make the problem go away if that sensor is the problem. Once proven that my old sensor is ok I put it back in and keep the cheap one for an emergency back. MAF and Crank made zero difference. Summary: I've swapped out the MAF, crank sensor, replaced the front O2 sensor, pressure / smoke tested the intake, monitored fuel pressure to look for fluctuations with a gauge, boost gauge to watch for fluctuations, replaced injectors with refurbished ones, every maintenance item has been replaced, logged every conceivable thing with the AP to look for any signs. The only things I have left are the cam sensor and coil. I picked up a used coil and will swap it one at a time, one per day and check for a difference. 10' CTS-V, A6, Airraid, 2.4 upper, ID850's, self tuned. SOLD:06' LGT Wagon. BNR16G, Catless UP, DOWN, Hexmods VB, Hexmods diff bushings, BIG TMIC. Best 0-60: 4.651 by AP 1/4= 13.678@100.73 mph, 1.945 60', Automatic transmission. Link to comment Share on other sites More sharing options...
firehawk618 Posted March 15, 2014 Author Share Posted March 15, 2014 I cleaned my MAF and the surge is less noticeable now... but would like to make it go completely away. My GT has 83,000 mile with a gutted uppipe and a AP stage 1 tune. I did not notice the surge at HWY speeds with cruise until about three weeks ago when I flashed my ECU with the AP stage 1. If yours started with the tune, flash it back to stock and really feel for it and see if it's still there, completely gone or slightly there..... Mine did it bone stock, AP stage 1, AP stage 2, bren tune. I really don't think the tune is my culprit. 10' CTS-V, A6, Airraid, 2.4 upper, ID850's, self tuned. SOLD:06' LGT Wagon. BNR16G, Catless UP, DOWN, Hexmods VB, Hexmods diff bushings, BIG TMIC. Best 0-60: 4.651 by AP 1/4= 13.678@100.73 mph, 1.945 60', Automatic transmission. Link to comment Share on other sites More sharing options...
SATSFYD Posted March 17, 2014 Share Posted March 17, 2014 ^Well since I cleaned the MAF I have not felt it... I drive 60 plus miles a day on the HWY. **There are two types of people in the world, those who build horsepower and those who buy it. Which one are you? Link to comment Share on other sites More sharing options...
SATSFYD Posted May 19, 2014 Share Posted May 19, 2014 Did not flash back to OEM, BUT did replace the spark plugs and I do not feel the surge any more. **There are two types of people in the world, those who build horsepower and those who buy it. Which one are you? Link to comment Share on other sites More sharing options...
firehawk618 Posted May 19, 2014 Author Share Posted May 19, 2014 Glad yours went away. I will say mine is almost non-existent anymore. To be honest unless I'm really looking for it I don't feel it anymore. I'm going to write it off as a ghost mystery unless it re-appears. For the record I never did change my cam sensor. I ordered one and they sent the wrong one. 10' CTS-V, A6, Airraid, 2.4 upper, ID850's, self tuned. SOLD:06' LGT Wagon. BNR16G, Catless UP, DOWN, Hexmods VB, Hexmods diff bushings, BIG TMIC. Best 0-60: 4.651 by AP 1/4= 13.678@100.73 mph, 1.945 60', Automatic transmission. Link to comment Share on other sites More sharing options...
fishbone Posted June 19, 2014 Share Posted June 19, 2014 Replaced rear 02 sensor today. No change in cruise, stumble is still there. A/F learnings, for now, after a reset, appear to be slightly different but need to drive more to confirm. At idle, A/F Learning will climb to 7-9%, and as soon as the A/C kicks in, it drops to 0.0. What would this suggest, if anything? Link to comment Share on other sites More sharing options...
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