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Old 09-09-2013, 01:38 PM   #1
paulharmo
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Default WGDC pegged at 0? AFR's in the 17s under med. throttle?

Really not sure what's going on here... But I'd be very appreciative if someone would take a look at these logs and tell me what they think. I only just got my AP this morning, and I wasn't exactly expecting to see this erratic of a behavior in logs...

https://docs.google.com/spreadsheet/...kE&usp=sharing

https://docs.google.com/spreadsheet/...UE&usp=sharing

-Paul
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Old 09-09-2013, 02:10 PM   #2
Cobb Tuning
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Quote:
Originally Posted by paulharmo View Post
Really not sure what's going on here... But I'd be very appreciative if someone would take a look at these logs and tell me what they think. I only just got my AP this morning, and I wasn't exactly expecting to see this erratic of a behavior in logs...

https://docs.google.com/spreadsheet/...kE&usp=sharing

https://docs.google.com/spreadsheet/...UE&usp=sharing

-Paul
Hi there.

What are all your mods? What exact map are your running? This is an 05 Forester XT? What octane gas are you putting in the car? How are you determining AFR - is this via an aftermarket wideband o2 sensor?

Your dynamic advance multiplier (DAM) has dropped to 0 - this means that there's the been a number of knock events. Wastegate duty can be set to 0 (to disable boost control) when the DAM drops low enough. The DAM dropping this low is completely abnormal and means there's something seriously wrong. This could be a mechanical issue, wrong mods used for the map, wrong gas used for the map, bad gas, etc.

Bill
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Old 09-09-2013, 03:38 PM   #3
paulharmo
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I apologise for the lack of information in my first post, I was very pressed for time, and I'm here to elaborate now.

My car is an '05 FXT with 4EAT. I'm currently running a Cobb OTS tune - Stage 1, 93 Octane, V3.00.

I've been using top-tier 93-octane gas since I bought the car. I was determining the AFR via the stock sensor, looking at the AP as I accelerated.

Current mods: Cobb SF intake, AVO Inlet, STi TMIC.

The car was definitely pinging hard when I first flashed the car to stage 1 - The first time I got past 5000RPM the engine knocked so badly it sounded like a can of marbles under the hood. I backed off quickly. I heard pinging once more, but it began to disappear - I assume because the DAM dropped. I did a bit of looking at live data, and I was, in fact, racking up a serious knock count at WOT (~20 in 2 seconds).

The AFR being so far off led me to believe that there was a boost leak... But that would make the AFR rich, correct? Maybe fuel pump going bad, clogged filter/injectors, or the FPR or its connections to the intake manifold?

Another thing I noticed early on is that the AP showed the vacuum to be ~10 at idle. Connecting a mechanical gauge yielded ~20 in.HG of vacuum. Does this point to a bad MAP, or is vacuum calculated using a different unit of measurement?
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Old 09-09-2013, 04:12 PM   #4
Chicago AJ
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You're running a map that isn't intended to be used with an intake, bigger intercooler, or turbo inlet. You could seriously damage your car by continuing to do this.
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Old 09-09-2013, 04:27 PM   #5
Cobb Tuning
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Originally Posted by paulharmo View Post
I apologise for the lack of information in my first post, I was very pressed for time, and I'm here to elaborate now.

My car is an '05 FXT with 4EAT. I'm currently running a Cobb OTS tune - Stage 1, 93 Octane, V3.00.

I've been using top-tier 93-octane gas since I bought the car. I was determining the AFR via the stock sensor, looking at the AP as I accelerated.

Current mods: Cobb SF intake, AVO Inlet, STi TMIC.

The car was definitely pinging hard when I first flashed the car to stage 1 - The first time I got past 5000RPM the engine knocked so badly it sounded like a can of marbles under the hood. I backed off quickly. I heard pinging once more, but it began to disappear - I assume because the DAM dropped. I did a bit of looking at live data, and I was, in fact, racking up a serious knock count at WOT (~20 in 2 seconds).

The AFR being so far off led me to believe that there was a boost leak... But that would make the AFR rich, correct? Maybe fuel pump going bad, clogged filter/injectors, or the FPR or its connections to the intake manifold?

Another thing I noticed early on is that the AP showed the vacuum to be ~10 at idle. Connecting a mechanical gauge yielded ~20 in.HG of vacuum. Does this point to a bad MAP, or is vacuum calculated using a different unit of measurement?
The MAP reading is fine -> 20 inHG is approximately 10 psi (AP always reads manifold pressure in psi).

Given the various pieces of evidence here, I would guess that a bad MAF sensor is the most likely scenario. A failing MAF typically causes you to run lean which is especially problematic at high load and can cause excessive knock. Given the severity of what you are seeing, I would go ahead and replace the MAF with a brand new OEM unit. You don't want to take chances with this sensor. It is a bit pricey though, so if you have friend with a Subaru you can swap sensors with (assuming they are not having any problems with their car), you can give that a try first (as a test). Whatever you do, if you replace the sensor, reset the ECU via the troubleshooting menu on the Accessport.

Beyond that, it could really be anything. If you've lapsed on your maintenance items (spark plugs, fuel filter, etc), then now would be a good time to take care of that. With a bad injector, you will typically have noticeable driveability issues (stumbles, bad idle, hiccups) and/or misfires. Same with bad ignition coil. A pressure or smoke test of the intake tract would be a good idea as well on a car this old.

The Cobb SF intake for these particular cars will work without with our OTS maps (no separate maps here). Turbo inlet and STi TMIC will not cause the problems you are seeing here.

Bill
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Old 09-09-2013, 04:33 PM   #6
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Also, do not do any more wide open throttle (WOT) or other aggressive driving (drive conservatively). If you do something that is an attempt to fix it, then rather than doing a WOT pull at first, reset the ECU and then drive through a full tank of gas without reflashing any maps or resetting the ECU. Then check your A/F Learning 1 A,B,C,D values via the live data function on the Accessport. These are your long-term fuel trims. Each individual value should be within around -5% to 5%. If any one or more is well outside of this, then likely you still have a fueling issue. In fact, you can do this test before purchasing the MAF sensor to see how bad they get (currently your logs show as bad a +7%).

Bill
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Old 09-09-2013, 04:59 PM   #7
paulharmo
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I will order a MAF tomorrow. In the meantime, I have switched back to the "stock" map, on which the car behaves less poorly.

I took two more datalogs - The first is on the 91oct Stage 1 map, and the other is on the "stock" map (I added a knock count to the second log).

From here on out, I will let the car run and reset its' adaptations/trims until the MAF shows up, staying off boost when I can. Do you suggest using the Stage 1 map or the stock map for this time?

Stage 1 91oct map:
https://docs.google.com/spreadsheet/...EE&usp=sharing

Stock map:
https://docs.google.com/spreadsheet/...VE&usp=sharing
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Old 09-09-2013, 05:27 PM   #8
paulharmo
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I've been having sporadic stumbling issues with this car - the plugs have already been replaced, the coil packs checked, crank sensor scoped, and fuel pressure checked at KOEO. The only reason I haven't replaced the fuel filter is that it's integral to the track and a pain to get to. If I can borrow one of my school's master fuel pressure gauge kits, I can try to do some engine-running pressure tests.
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Old 09-10-2013, 08:39 AM   #9
Cobb Tuning
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Quote:
Originally Posted by paulharmo View Post
I will order a MAF tomorrow. In the meantime, I have switched back to the "stock" map, on which the car behaves less poorly.

I took two more datalogs - The first is on the 91oct Stage 1 map, and the other is on the "stock" map (I added a knock count to the second log).

From here on out, I will let the car run and reset its' adaptations/trims until the MAF shows up, staying off boost when I can. Do you suggest using the Stage 1 map or the stock map for this time?

Stage 1 91oct map:
https://docs.google.com/spreadsheet/...EE&usp=sharing

Stock map:
https://docs.google.com/spreadsheet/...VE&usp=sharing
The reported knock is excessive with either map. I would not do any more WOT pulls at all until you figure it out - you are putting your engine at risk. More important than the map is to simply try to stay out of boost (drive very conservatively).

Bill
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Old 09-11-2013, 12:03 PM   #10
paulharmo
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Having cleaned my MAF sensor thoroughly and run about half a tank of fuel since yesterday morning, I began to read live data from the AP as I got under light boost - Instead of AFRs spiking, they richened like I'd expect them to. One quick jab of near-WOT yielded an AFR of 11.1 or lower.

It's safe to say that there's a huge difference in the behavior of the car now. Much less stuttering under light load, and obviously the AFRs are back in line.

What should be my next course of action? A part-throttle pull to ensure that the engine isn't knocking itself apart anymore?
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Old 09-11-2013, 12:15 PM   #11
Cobb Tuning
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Originally Posted by paulharmo View Post
Having cleaned my MAF sensor thoroughly and run about half a tank of fuel since yesterday morning, I began to read live data from the AP as I got under light boost - Instead of AFRs spiking, they richened like I'd expect them to. One quick jab of near-WOT yielded an AFR of 11.1 or lower.

It's safe to say that there's a huge difference in the behavior of the car now. Much less stuttering under light load, and obviously the AFRs are back in line.

What should be my next course of action? A part-throttle pull to ensure that the engine isn't knocking itself apart anymore?
Yes, sometimes cleaning can be a fix but sometimes it helps but does not completely solve the issue. So, it gets better but the sensor is still under reporting airflow. Personally, if you have any confirmation that the MAF sensor is the problem, then I would just replace it with a new one unless you have an aftermarket wideband o2 where you can verify fueling at higher load (stock sensor is not accurate in this regard).

Bill
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Old 09-11-2013, 12:28 PM   #12
paulharmo
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I'll continue to take it easy, then. A new MAF will be here tomorrow morning.

Should I reset the ECU after installing the sensor? Another tank of gas or so before I push it?
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Old 09-11-2013, 12:39 PM   #13
Cobb Tuning
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Originally Posted by paulharmo View Post
I'll continue to take it easy, then. A new MAF will be here tomorrow morning.

Should I reset the ECU after installing the sensor? Another tank of gas or so before I push it?
Yes, reset the ECU after you install the sensor and then run through a tank of gas and then make sure each individual A/F Learning 1 A,B,C,D fuel trim is within around -5% to 5%. If so, then try a WOT pull (with log).

Bill
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Old 09-11-2013, 11:14 PM   #14
Ryan321
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As bill said do not do wide open pulls. You can try the 91 octane maps and run 93.
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Old 09-18-2013, 09:22 PM   #15
paulharmo
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After some time to learn with the new MAF sensor, the car seems to be running much better. AFRs are under control, and the A/F learning B,C,D are all within 5%. A is more like 8%, but that's idle, and idle speed and AFR are correct.

I did two pulls this evening. No knock except shift point false positives, as far as I can tell. I'm still not hitting my boost targets, however. re-tightening all boost hoses did not seem to affect the boost level at all.

Are there any abnormalities that you can pick up here? Anything else I should be trying in order to hit boost targets other than tightening the wastegate arm or smoking the intake tract?

https://docs.google.com/spreadsheet/...lE&usp=sharing

https://docs.google.com/spreadsheet/...kE&usp=sharing
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Old 09-20-2013, 11:22 AM   #16
Cobb Tuning
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These logs definitely look better, but given the issues you've had recently and the age of the car, I'd say that a pressure/smoke test of the intake tract is a must. Once that is confirmed to be good, you can make steps to raise you boost levels (tightening wastegate arm, raising wastegate duty cycles, etc.) to get closer to the target.

Chris
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