Oberon

I will definitely start looking for a boost leak. I will look myself and talk to the mechanic across the street from where I work, easy to drop the car of and walk to work come back later, especially if he waits and has it up when I can take a look better. For me the DAM drop goes away when the cooler/colder weather hits. It started late last summer, as I started looking into what the cause was it gone by mid fall. No issues till the weather got warmer this spring. Even a cooler morning the DAM will work its way back up. I try to drive with little to know boost, when I have any I'm going up a steep hill but keep the RPM lower and take it slow. Sadly I don't have another option for a car why I really want this fixed. I'll see what I can do this weekend.

Good to know thanks. I noticed the same with the DAM, drops most under moderate load, like going up an incline, my drive to work is quite hilly. I have actually taken it to a shop, but what should I have them test? The shop I usually go to or even local dealer (they did the head gasket what a nightmare dealing with them), take it for a drive and don't notice anything. All the issues show up in the data logs, with out the data logs, unless like me you drive the car daily you wouldn't notice the engine sounding different, the whole feel of the car is off. The show I go to near my job listens to me and will look at anything I ask. Boost leak sounds like what I was thinking but how to test for it, is the turbo just going? Wastegate gunked up? I tried to contact dyno shops, sadly none near by and they weren't very good with communication. The one that got back to me said they would want my car for like 3 days and they were way out in the country 70+ miles from me so not even near a place to rent a car. Thanks for the help and feedback.

Paid better attention to the AFR while driving it goes above 15 when my foot is off the gas. Moment i give the car any gas it drops down below 14.7, is that normal? I attached my datalog from my drive home, normal driving. it just rained a little and temp dropped to low 70's so DAM actually improved a bit but still much to low. I need to get back under and look but I think my down pipe is cracked at the weld before the CAT, couldn't see very well. Really hate to have to buy another one if I can even find the same one, if it is cracked may be able to weld it. Data log afternoon 7-22-2020.csv

My AFR when I have 0 or less boost seems to me to be much to high. It is 15-20! Now since I'm using the OEM O2 sensor and not a good wide band is this accurate? I thought anything over 14.7 was lean. Now when I do have boost the AFR drops down to under 13 and goes down as boost goes up which I believe is what I want from what I understand.

I thought about the gas too because at one time I was getting cheaper 93. I looked into the best places locally for gas and I go to a Sunoco near my house for my gas now. The only change I noticed is my gas millage improved a little but sadly the knocking/ DAM drop didn't go away, maybe not quite as bad as last summer and this summer has been a hot humid one here but still bad drop. I'll look into the carbon build up and try to see if I am running lean. Do I watch the AFR to tell if I am running lean? What should the numbers be for my car? Thank for the help, this is great things I had no idea to look into.

I do watch my intake temp and datalog it. on a hot 90+ F day with >75% humidity the intake temp gets up between 120-130 at slow speeds or stopped. It drops down to 110 range when I get up to 60 mph. Is that to much higher than ambient temp? How do I check for excessive carbon buildup in the cylinder or running lean? What should I be looking for? I'm noticing these DAM drops with normal driving with limited boost. Sadly with the down pipe if I try to run a stage 0 or 1 map I get a check engine light because of the lower O2 sensor. However it takes a bit so I have tried and still see the DAM drop in hot humid weather. Thanks

As far as mods the down pipe and exhaust are all I've done. I do use a K & N air filter instead of the OEM one. Anything else I did was breaks and suspension related. Basic Stage 2 setup. I'm using Cobb's OTS stage 2 91 Map normal wastegate. I use the best gas I can find locally 93 at a Sunoco. My concern with the DAM drop is that it seem a bit excessive now. It use to drop to .812 in the summer maybe .75 then go back to 1.00 on a cool morning. My drive home yesterday it dropped to .128. This morning was still in the mid 70's and high humidity so it only got up to .5. That seems sever to me, but IDK. It does seem to be better on a low humidity day but I'm in upstate NY so those are rare. You can feel and hear the difference when the DAM gets below .75. I contacted cryo tune about an e-tune https://www.cryotuneperformance.com/etuning Thinking that the issue may be my tune and read the same in forums. Dave wrote back to me saying the DAM drop was a concern and that Cobb's OTS tunes are decent they would be concerned with doing a tune for my car. Dave recommended I get a compression test which I did and nothing was way off. He didn't think a tune would help which surprised me. Should I contact a different e-tune place Cryo tune was highly recommended? Thanks for the comments!

I hope someone can give me some ideas of what else to check on my car as I am at a loss. To start, my issue is my car drives great all winter long. Once the weather starts getting warm my DAM drops, 90+ humid day the DAM can get to almost 0 (.068). If the next morning it is cooler (low 60's) the DAM will start to work its way up again till the heat hits. This is all normal driving very limited boost. Fall weather hits with consistent < 60 F temps and DAM will eventually work its way back to 1 and be fine till later spring. Now as to what I've checked and or replaced. First I'm running stage 2 Cobb OTS 91 map. Running 93 good quality gas. My car has 153k miles on it with Invidia catted down pipe and Borla exhaust. Jan 2019, replaced head gasket, spark plugs, clutch, timing belt and radiator. Summer 2019 replaced all 4 coil packs. Spring 2020 replace up stream O2 Sensor. Recently cleaned MAF though will do it again to make sure. Just had compression test done Cylinder 1 was 145 PSI, Cylinder 2 & 4 150 PSI Cylinder 3 155 PSI. The spec says they should be 171 PSI, so tad low but expected with 153k miles. I was more expecting one to be much lower than the rest given the issues I'm having. Intermittently I will see Feedback Knock less than -2.8 but not often, the DAM drops when Fine Knock learn stays negative. Once the temps drop and stay below about 60 it all goes away. I do think I need a new turbo, could that cause this? I see TD boost error ranging from -8 to +24. When the weather is cooler and I feel safer doing a hard pull in 3rd gear there is TD boost error around 2-4 with >10 PSI boost. In general I've never driven my car hard. But figure with over 150k miles my turbo is likely at the end of it's life. But how do I test it? Could their also be issues with the waste gate? Smoke test last year showed no leaks and had this same issue last summer. Am I way off about turbo? I'm at a loss what to test and don't want to spend money randomly replacing things. I'd like to keep the car a while longer especially since the new Legacy so far stinks, now if they come out with one that is a manual and more power I'm in! Thank you for any help anyone can provide. I can provide data logs if anyone wants to see them.

Finally got to moving the spark plug and coil pack from cylinder 4. The spark plug gap was .025" increased it to .027", since the NGJ plugs have a spec of .027"-.030". Plus moved the plug to cylinder 2. No change I'm still seeing the cylinder 4 knock sum increase quite a bit. I often notice the Fine Knock learn will reduce the timing even when the feedback knock has remained 0 for a long time. Some times as much as -5 degrees. Often this coincides with cylinder 4's knock sum being incremented yet no feedback knock. Anyone have any other idea's as to what could be going on? I'm at a loss as to what I should check. I did find some older data logs from February, I noticed even then cylinder 4's knock sum was much higher than any other cylinder, but the DAM stayed at 1.

Yes I put in OEM coil packs and SKG SILFR6A spark plugs, they appeared to be identical to the OEM ones from what I could see. This week I will check the spark plug gap in cylinder 4, then swap the coil pack and spark plug to a different cylinder. If the problem moves then I just need to determine if it is the spark plug or coil pack. Hopefully pick up some injection cleaner tomorrow as well. I always run 93 octane fuel just running the stage 1 91 map to be safe for now. Why when I just drive in a lower gear than I normally would for the given speed do I find the DAM getting a little better. If I cruise in say 6th gear on the thruway it drops. If I accelerate harder often the DAM will go up to 1 or close. Anything else I should consider?

Thanks for taking the time to look the log over, I noticed that as well with cylinder 4, just wasn't sure really what to check with it or it that was the only issue. Spark plugs are 6 months old, changed them at the same time as head gasket, I put in NKG SILFR6A plugs. But I'll double check them definitely could have had a bad one. Data logged on my way home and tried to push the car some, was able at one time to get it up to 6000 RPM in 3rd. Surprise driving more aggressively and the DAM went up to .938-1. Cylinder 4 still shows more Knock sum however. What causes the DAM to improve when you drive more aggressively (turbo has positive boost more even if only a few PSI) datalog100-cut.csv

I've been trying to read though as much information as I can on understanding my datalogs and DAM but just not having any luck trying to figure out what is going on with my 2011 LGT. If anyone can help me interpret my logs it would be greatly appreciated. I just had new ignition coils put on and ever since the DAM can go from 1 all the way down to .125 then work its way back up to about .812. I was running stage 2 91, now I'm back on stage 1 91, no real change. I'm going to try stock tune tonight. The car runs much smoother with the new ignition coils despite the constantly changing DAM. What promoted it is the 2nd cylinder coil died. All the coils looked quite beat up from winters in upstate NY so figured best to just replace them all. I've had quite a bit of work done on my car the last year, so some information on everything, it may get long, sorry. My car has about 137k miles. Till the last year have never had any real problems. I have a invidia catted down pipe, Borla exhaust and K/N air filter. I have been running stage 2 93 for quite a few years. Just bumped it down in May to 91 since I was out of town and to many gas stations only have 91. Dec 2018 I had the head gasket done, new radiator, hoses, timing belt and clutch. After the work I noticed the car had more power but would I guess you could say stutter a little when pulling hard in 3rd or 4th gear and boost was over 13 psi. It didn't always happen but was repeatable enough if you pushed the car hard. Based on my research it seemed like the fuel pump wasn't keeping up as nothing really showed up odd in the datalogs. I had the local shop check it and they said the same thing my fuel pump wasn't keeping up to just dial back my tune a bit. 4th of July weekend suddenly I got a check engine and a cylinder 2 missfire message. Figured it was the ignition coil. Sadly I did have to drive the car on 3 cylinders to the shop. Right after having the new coils put on I noticed the stutter that was there was gone, it pulled hard now right up to about 16.8 PSI nice and smooth. I plugged in my AP and started logging. That is when I noticed the DAM dropping a lot, if I did a harder pull at times it would go back to 1 or close. Not always. So now I'm watching it non stop. It goes up and down, mornings it seems to be better, could it be the cooler temps? My drive to work is about 40 miles mostly 55-65 mph. I attached my datalog from the drive in this morning. I didn't really drive hard at any point. I had just put in the stage 1 91 map so the CPU was cleared. My car always starts with the DAM at .812, in the past it would just work its way up to 1 and stay there. Now it worked up to 1, the started dropping all the way down to .5. Am I data logging all the right things? I'm not really sure what to even look for to try and fix. Thank you so much for any insight that can be offered. datalog99.csv