I guess fueling is the next logical step. Besides that, I'm a little stumped at the moment. 
Lean with Missfire's
- Thread starter Mason Johnson
- Start date
Alin
Diehard Car Enthusiast!
@Mason Johnson , out of curiosity... Pull back the passenger's side carpet in the foot well and take a look at the ECU. Ensure that your car doesn't have a piggyback attached to the ECU. This is somewhat reminding me of my car when it wasn't getting tuned correctly. The culprit ended up being that I had a TurboXS piggyback ECU that was interfering. It's another thing we can rule out for the time being. Take a picture as well, please.
Mason Johnson
New member
Think I found the issue. I unplugged my maf sensor and the car runs way better. No miss and a constant idle. I also replaced the maf sensor and still no luck. Reading on the old maf was at about 3 g/s. The new maf sensor started out reading 5 g/s on a cold start then as it warmed up it fell back down to 3 g/s. The new maf is aftermarket which could be why but not sure. What's the normal voltage for the maf sensor? Also doesn't look like the car has a piggyback system.
Umm...I'm not sure what the nominal idle voltage is, but operating range is typically 1 to 5 VDC. A bad/dirty MAF is definitely something to be concerned about. Did any of us mention the MAF beforehand?
Sent from my SM-N975U using Tapatalk
Sent from my SM-N975U using Tapatalk
Alin
Diehard Car Enthusiast!
Umm...I'm not sure what the nominal idle voltage is, but operating range is typically 1 to 5 VDC. A bad/dirty MAF is definitely something to be concerned about. Did any of us mention the MAF beforehand?
Sent from my SM-N975U using Tapatalk
Yes, you did on multiple occasions. :tup:
Mason Johnson
New member
UPDATE: So here's where I'm at. New front o2 sensor. New cylinder 1 injector. New intake gaskets. Vehicle was taken to Subaru for diagnostics. Subaru found that the intake was leaking along with a bad injector on cylinder 1. Vehicle was also leak down tested with positive results of a healthy engine. Since getting the car back the cel's are gone but I'm still getting a rough idle. I'm resting at about 550 rpms when warmed up. Maf sits at around 3.5-4 g/s and the voltage sits at 1.2-1.3 which I'm being told it correct. Now I'm stuck again. Everything is fine under power no stutters and car feels fine. As soon as I stop at a light the car drops rpms like its gonna stall then go back to 550rpms with rough idle. No lean codes, no misfire codes at this time. Could this be a tuning issue?
Still running Cobb OTS map for stage 2 91ACN/ARN LWG
AFR range is 14.7-17. Car started out with 17-24. Definitely made a dent in correcting my fuel trim.
Still running Cobb OTS map for stage 2 91ACN/ARN LWG
AFR range is 14.7-17. Car started out with 17-24. Definitely made a dent in correcting my fuel trim.
Alin
Diehard Car Enthusiast!
Whenever you have the car turned on again, plug in your AP and go to Tuning, then check what the RPM is set to. If it's set to the default parameter (can't think off the top of my head what it is), then you can increase it by a couple hundred RPM maximum. If it's set under the default parameter, just increase it. I want to say it's around 750-800 RPM?
Mason Johnson
New member
I'm actually already doing this. I have it set currently at 850 rpms but I'm still getting a rough idle.
Alin
Diehard Car Enthusiast!
So, with car turned on, the idle RPM is ~550, and the AP in your hand shows ~850? Adjusting RPM in that moment, whether increasing or decreasing, nothing occurs?
Mason Johnson
New member
Sorry. Let me rephrase. When first starting the car with zero adjustments it's at 550 rpms at idle. I raised the idle to 850 to see if it would improve and it did not.
Alin
Diehard Car Enthusiast!
You don't live far from @Eagleye. You should talk to him about meeting up. It's very different helping in person compared to being behind a computer screen. He has plenty of knowledge and can help out. :tup:
-What is the idle RPM during cold start? (I think default is right around 1,500 RPM.)
-550 RPM is the idle when the car is warmed up, correct?
-When the car is running at ~550 RPM, what happens when you input an RPM increase or decrease through the AP?
"Still running Cobb OTS map for stage 2 91ACN/ARN LWG"
Also, why are you running on 91 octane? Doesn't PA have 93? Have you tried the Stage 2 93 OTS map since the recent repairs?
-What is the idle RPM during cold start? (I think default is right around 1,500 RPM.)
-550 RPM is the idle when the car is warmed up, correct?
-When the car is running at ~550 RPM, what happens when you input an RPM increase or decrease through the AP?
"Still running Cobb OTS map for stage 2 91ACN/ARN LWG"
Also, why are you running on 91 octane? Doesn't PA have 93? Have you tried the Stage 2 93 OTS map since the recent repairs?
Mason Johnson
New member
I'll message him. Car starts at 2k usually at first start then creeps down to 1500 then slowly down as it warms up. 550 rpm is warmed up, correct. Car will clear up a little bit but no visible changes it does seem to mellow out a little bit but not all the way. We do have 93. I'm running the 91 because I was told to here but I guess I should probably change that now that all the work has been done.
Alin
Diehard Car Enthusiast!
Swap your map to the Stage 2 93 OTS map. The normal wastegate one. Let the car relearn the parameters (I assume you know how), then go for a little cruise. Then, report back if the idle issue is still occurring. If you still have 91 octane fuel in the tank, DO NOT WOT!!!!! I would also be cautious with boosting. (I would recommend you drive like a grandma if you have a lot of 91 octane fuel remaining until you can refuel the entire tank with 93. Don't mix 91 with 93.)
Mason Johnson
New member
If you don't mind explaining the relearn parameters. I also never filled the car with 91. It's always on 93. So currently I'm on the 91 tune with 93 fuel.
Alin
Diehard Car Enthusiast!
That is great to hear! :tup:
This is how I do it (I'm more anal than most people when it comes to this):
1) ensure car is warmed up and then turned off
2) go through the procedure of flashing a new map
3) once the map is flashed, take out the key from ignition for 30 seconds
4) turn on ignition to accessory for 15 seconds
5) turn on car (DO NOT TOUCH THROTTLE)
6) let car idle for 10 minutes stationary
7) begin driving like a grandma shifting around ~2,500-3,000 RPM for 15 minutes, then another 10 minutes to ~4,000 RPM (gentle driving with NO boosting)
8) boost a little bit (no more than 5 PSI) up until around ~4,000-4,500 RPM
9) if everything seems fine, do one 75-80% throttle acceleration to red line (NO WOT!)
10) if the heavy acceleration seemed fine, I do one 3rd gear WOT run from ~3,300 RPM in a controlled location (I have a strip of road where it turns from 25 MPH to 55 MPH and there isn't much traffic)
You have to monitor AFR and knock at all times. I don't know which AP version you have or what gauges you have hooked up. I have an AEM UEGO AFR gauge and a Tactrix cable with Romraider. If you have a V2 AP, then you can only monitor one parameter. If you have the V3 AP, then you can have up to 6 parameters on screen at the same time.
-Do you have a V2 or V3 AP?
-Do you have any gauges hooked up in the car?
Note: If your oil hasn't been changed recently, do NOT WOT.
Edit: I had to look back through the thread since it's been a while. It sounds like you only have the Cobb AP that you're going off of. The AFR that the AP reads is not accurate. If you don't have an external AFR or wideband, you won't get an accurate reading. So, please address what gauges if you have, if any. Also take a couple of pictures of your interior, dash, and center console.
Mason Johnson
New member
Only thing I have to monitor the engine is my v3 AP. Only gauge I have is the boost gauge on the steering colum. I re-tuned the car. Check engine light popped up for p0171. Extreme fuel trim. I have no idea what it could be now. Before the tune I was getting no cel. Car does idle a little better now. My issue is I need the car inspected. I can't pass emissions and I can't get a waiver because it's already been waived once. I've spent over a grand trying to solve this issue and it just keeps coming back.
Alin
Diehard Car Enthusiast!
Unfortunately, there isn't much I can do behind a computer screen and you're roughly 6 hours away, which isn't exactly close. Best bet right now is talk to [MENTION=692]Eagleye[/MENTION] and meet up with him. Physically being there with the car is completely different than trying to do it on a forum.
Grinder34
Track Monkey
What does PA do for inspection? OBDII? Sniffer? Visual? There are always ways to pass...
Mason Johnson
New member
All 3. no cel's. Only way you can get an inspection for emissions is to pass all monitors with no codes
