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Old 07-17-2012, 09:22 AM   #1
konsept
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Default 2800-3000 RPM Mis-firing in ALL gears!! Help please! :(

Hey all,

Just looking for ideas on what the issue with my car is.

My tuner pulled logs and sent them to COBB for further analysis, however they think it's the Deatschwerks 1000cc injectors.

I don't know the exact details from a technical stand-point, but my tuner said he encountered a similar issue with another STI running ID 1000cc injectors (different brand).


How it happens:

If I'm driving casually / lightly (less than 25% throttle), it'll bog for a very split second between 2800-3000 rpms. Once it's past 3000 rpms, there are no further issues.

If I press the throttle harder than 25% to about 90%, the bogging / misfiring become more evident and VERY frustrating. If I'm WOT, the nose of the car drops when it reaches 2800-3000rpm then picks up and carries on (from an outsider, it'll look like I'm "shifting").



So are there any known issues with running 1000cc injectors with these cars? What should I do next?

Honestly, I can't stand this car anymore with this issue.




Very quick run down of things that are air and fuel related:

- 2011 STI hatch
- Blouch dominator 2.5 xtr turbo
- deatschwerks 1000cc injectors
- 1-step colder spark plugs
- deatschwerks fuel pump (the drop-in one... 65wc or something like that)
- AMR BMI intake
- AMR front mount intercooler
- COBB AccessPort (using SpeedDensity and protuned)
- TGV Deletes (cosworth)


Datalogs:

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Old 07-17-2012, 03:42 PM   #2
imma_stocker
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Its something in the new FPR setup Subaru switched to in 08. Actually a common issue, not sure why your tuner isn't aware of it. The MECHANICAL (proper) fix is to upgrade your FPR and ditch the stock balancing hoses and other junk they put in. You can also swap in an OEM FPR setup from earlier year STIs (04-07 STI) if you want to keep stock setup. You'll need the FPR and lines running to and from your fuel rails to do the swap.
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Old 07-17-2012, 04:36 PM   #3
konsept
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Quote:
Originally Posted by imma_stocker View Post
Its something in the new FPR setup Subaru switched to in 08. Actually a common issue, not sure why your tuner isn't aware of it. The MECHANICAL (proper) fix is to upgrade your FPR and ditch the stock balancing hoses and other junk they put in. You can also swap in an OEM FPR setup from earlier year STIs (04-07 STI) if you want to keep stock setup. You'll need the FPR and lines running to and from your fuel rails to do the swap.
What are my upgrade "options"?

Just need to weight out whats the most effective solution (either upgrading or switching to the earlier years fuel pressure regulator setup).

Mind you, there is a possibility that I *might* take my build further later.
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Old 07-17-2012, 04:55 PM   #4
cdoliver
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It's a fueling issue. had it on my 2011
Changing the FPR from an earlier year may or may not help
a tuner may or may not be able to tune it out
I bet you didn't notice it until you changed the turbo and injectors
I had the same problem and my tuner tried to tune it out for many weeks, changed out the fpr, tried different injectors, different fuel pumps. nothing fixed mine so I eventually got rid of the car.
If you want to read more about it(you aren't the first to have this problem) do a search for "08+ hesitation" or "low rpm stumble" lots to read, I've read every page.
I came across this post recently and you should read it because it may be an option for your to check out. looks like the guys at top speed may know how to get rid of it. maybe, maby not.
good luck to you.
Quote:
Originally Posted by threelete View Post
For starters I logged this AM on the way to work
@ WOT:
.80 Lambda - Max duty cycle was 92%

History of my car.

1000k- flashed to Cobb Stage 1- 93
1500- added Cobb SF and Flashed Stage 1 SF 93 octane
2200- Added Invidia DP mated to stock catback, Flashed Stg.2
8500K- drove to Cobb Plano. 20gxt7cm, Walbro 255, ID 1000cc, Grimmspeed EBCS, E85 and 93 Tunes. 373/372 on Mustang dyno
13,500k- #4 cracked. Sent car on truck to Topspeed
Got back: Car had 16,000k on it last fall, Topspeed broke it in.
I have 33k now. I'm high mileage driver

SS1 forged CP block installed (new block), Aeromotive FPR, Aeromotive 340 fuel pump (I'll explain), Crawford AOS.
Got the car back with E85 and 93 tunes. there was E85 in the tank when I first drove it and it felt basically the same(386/412) dyno jet.
While my car was getting broken in Topspeed called me and asked it I had noticed a big hesitation between 2500-2900 rpms before the car failed and I told them I had!

Well, the car was still doing it with the new engine.

BEFORE THE PISTON BLEW HERE ARE SOME SYSMPTONS I WAS SEEING: My Walbro had started getting very loud before I had a piston issue on stock block. I sent logs to Cobb and they said it was fine. the walbro was making the start up hum noise longer and sometimes for an entire trip it would hum .Then one day I'm driving on a 98 degree day and not even driving hard and when I stopped the car threw a code? and was shaking. I sent logs to Cobb again and this time they confirmed bad misfire. Local compression check verfied. When I would start the car it was skipping #4, it was obvious at idle. My oil levels were checked weekly and they were OK, very small losses over 1500 miles.

SO, when Topspeed was still seeing the hesitation on the new engine I got worried. they replaced the Walbro with the Aeromotive 340 and also installed an Aeromotive FPR. The problem went away. So, my best guess was that I had a fueling issue. Originally when I left CObb i was told to continue using stock Subaru or Equal Oil. Oil change intervals were not stressed to me so I went with 2000 mile intervals, which Topspeed recommended was borderline too high. I'm going with 1500 mile intervals now and using eneos 0w50 or motul 10w40 when running E85 only. I do 3000 on 93 through the winter and I stick with the good oil. the Crawford AOS is good insurance also. I put the EL headers on also and the increased engine Vol. Eff. probably helps too. Bottom line after reading upon end is that our cars seem to fail selectively. Letting the car warm up in the AM, etc. all helps. When I start it in the AM and it's initially very loud and settles down after about :30 seconds then I sit for a minute before I go. I treat her like one of my kids now.

Another key thing Doug Wilks noticed on the dyno last week was that Fuel Pressure was low at start up. One of my lines on the fuel pump was loose. The toggle on the plastic body of the was slightly bent so the line was slipping. he wired tied it so it can't slip now.

I hope this helps.

Brian

Last edited by cdoliver; 07-17-2012 at 05:01 PM.
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Old 07-21-2012, 09:06 PM   #5
MADMIKE874
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I am currently have the exact same issue with my 2010 STI, just did a 20g Turbo, 1000cc ID injectors, dw65 fuel pump, FMS FMIC, ect, everything went great with the tune drove the car home no problem. woke up the next morning and went for a canyon cruise up and down the canyon was great. Once I got on the freeway I put the car in cruse about a 4 miles later it thru an engine light. I got off the freeway and stopped at a local pep boys and had them run the code, came up with a system to lean bank 1. Called the tuner he said clear the code should be fine. Well from that moment on it stutters really bad from 2700 rpm to 3000 rpm in every gear every time. Even if cruising on the freeway at a constant speed if it is in the 3000 rpm range it will stutter the entire time until you either speed up or slow down out of that Rpm range. We did a log on the car and numbers were all over the place based on where we were on the dyno. Car was pulling like 6 deg of timing through out the rpm cycle. One other thing was that the intake temperatures were really high. When we were on the dyno "in a cool shop with the bumper off and fans blowing the whole time " intake temps were only reaching about 120 but when logging on the streets with out side temps at about 103 the intake temps were getting up over 200. So we first checked for leaks air/fuel and everything looks good. Next we are going to work on temperature by re routing intake/intercooler pipes because the current set up has the hot side pipe running on the intake side so we are switching them around. I also orders some new headers and up pipe that I took to be high temp ceramic coated . So once this is all complete I will chime in again hopefully it fixes it.
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Old 07-21-2012, 09:36 PM   #6
cdoliver
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Quote:
Originally Posted by MADMIKE874 View Post
I am currently have the exact same issue with my 2010 STI, just did a 20g Turbo, 1000cc ID injectors, dw65 fuel pump, FMS FMIC, ect, everything went great with the tune drove the car home no problem. woke up the next morning and went for a canyon cruise up and down the canyon was great. Once I got on the freeway I put the car in cruse about a 4 miles later it thru an engine light. I got off the freeway and stopped at a local pep boys and had them run the code, came up with a system to lean bank 1. Called the tuner he said clear the code should be fine. Well from that moment on it stutters really bad from 2700 rpm to 3000 rpm in every gear every time. Even if cruising on the freeway at a constant speed if it is in the 3000 rpm range it will stutter the entire time until you either speed up or slow down out of that Rpm range. We did a log on the car and numbers were all over the place based on where we were on the dyno. Car was pulling like 6 deg of timing through out the rpm cycle. One other thing was that the intake temperatures were really high. When we were on the dyno "in a cool shop with the bumper off and fans blowing the whole time " intake temps were only reaching about 120 but when logging on the streets with out side temps at about 103 the intake temps were getting up over 200. So we first checked for leaks air/fuel and everything looks good. Next we are going to work on temperature by re routing intake/intercooler pipes because the current set up has the hot side pipe running on the intake side so we are switching them around. I also orders some new headers and up pipe that I took to be high temp ceramic coated . So once this is all complete I will chime in again hopefully it fixes it.
this is why many shops tune with the hood down and fans blowing on the front of the car to simulate real world temp conditions.
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Old 07-22-2012, 01:28 PM   #7
konsept
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I'm in the process of getting the Aeromotive FPR. Not sure on timelines, but I hope I'll have it ready to be installed by next weekend and have my tuner have a go at it.

Fingers crossed this issue gets resolved. Permanently.

Quote:
Originally Posted by MADMIKE874 View Post
I am currently have the exact same issue with my 2010 STI, just did a 20g Turbo, 1000cc ID injectors, dw65 fuel pump, FMS FMIC, ect, everything went great with the tune drove the car home no problem. woke up the next morning and went for a canyon cruise up and down the canyon was great. Once I got on the freeway I put the car in cruse about a 4 miles later it thru an engine light. I got off the freeway and stopped at a local pep boys and had them run the code, came up with a system to lean bank 1. Called the tuner he said clear the code should be fine. Well from that moment on it stutters really bad from 2700 rpm to 3000 rpm in every gear every time. Even if cruising on the freeway at a constant speed if it is in the 3000 rpm range it will stutter the entire time until you either speed up or slow down out of that Rpm range. We did a log on the car and numbers were all over the place based on where we were on the dyno. Car was pulling like 6 deg of timing through out the rpm cycle. One other thing was that the intake temperatures were really high. When we were on the dyno "in a cool shop with the bumper off and fans blowing the whole time " intake temps were only reaching about 120 but when logging on the streets with out side temps at about 103 the intake temps were getting up over 200. So we first checked for leaks air/fuel and everything looks good. Next we are going to work on temperature by re routing intake/intercooler pipes because the current set up has the hot side pipe running on the intake side so we are switching them around. I also orders some new headers and up pipe that I took to be high temp ceramic coated . So once this is all complete I will chime in again hopefully it fixes it.
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Old 07-21-2012, 10:01 PM   #8
MADMIKE874
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So you think if we would have tuned it with the Hood down we would not have these problems? Cause I don't!!
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Old 07-21-2012, 10:15 PM   #9
cdoliver
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Originally Posted by MADMIKE874 View Post
So you think if we would have tuned it with the Hood down we would not have these problems? Cause I don't!!
No I don't. It would have been better, but I don't think re routing your intercooler pipes will help temps either. I don't think temps are your problem, honestly.
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Old 07-21-2012, 10:12 PM   #10
MADMIKE874
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I can definitely see your point as it makes sense, but there is no way to simulate real driving temps in 100+ summer heat for longer than 15 second pulls. So there is still a big issue some where that we are trying to eliminate right now we are working on heat. Car drove great for one day in the heat and then the next in nice cool air up in the mountains,
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Old 07-21-2012, 10:35 PM   #11
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I don't necessarily think that heat is my only issue either like I said we are checking into everything, I am giving my input on this issue as i am experiencing first hand. and heat seems to be a factor. But Yeah I think that swapping my intercooler pipes around will help alot. since the cold side pipe it constantly about 30 colder than the hot side. Which will help the intake.temps since it is basically resting on the fmic pipe making it hotter. This combined with coating the headers should drastically reduce heat temps.
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Old 07-21-2012, 11:44 PM   #12
cdoliver
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what does it do when you reset the ecu? the reason why I asked is because the stutter you are describing usually is a learned over a day or so. usually takes a day or so to learn itself into your tune. If you reset the ecu it will probably go away until it relearns. It is fuel trims related. watch your a/f ratio while it is stuttering you will see it jumping all over the place

Last edited by cdoliver; 07-21-2012 at 11:49 PM.
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Old 07-22-2012, 12:22 AM   #13
MADMIKE874
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I did a hard reset on the first night that it happened then drove it to work the next morning and had the same issue. Then drove it to the tuners shop where it has been for the last week getting the pipes done up as Well as waiting for the new headers to get coated. Once I get everything done we are going to run it and see it where we are. It don't really make sense to me that heat is the only cause but giving the fact it was cool out side in the morning to the canyon and really cool up in the mountains and did not have an issue until. I got to the freeway in the middle of the day when it was hot. I understand that others have had issues with the FPR. That would be my next guess if this don't help.
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Old 07-22-2012, 12:28 AM   #14
MADMIKE874
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It is also really strange to me that it only dose it in the exact same spot every time, but its fine right after 3000 rpm all the way to red line if it was a fuel issue would you not see it all the way across the board?
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Old 07-22-2012, 09:07 AM   #15
cdoliver
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Originally Posted by MADMIKE874 View Post
It is also really strange to me that it only dose it in the exact same spot every time, but its fine right after 3000 rpm all the way to red line if it was a fuel issue would you not see it all the way across the board?
no it's on the open loop closed loop transition. Your tuner isn't going to be able to see it unless they have a dyno that they can put a load on to simulate low rpm stress on the motor like driving slightly up hill in 6th gear at 65mph. you probably had it in 6th gear on cruise control and started going slightly uphill the first time you noticed it.

Did the problem go away briefly when you reset the ecu?

Last edited by cdoliver; 07-22-2012 at 09:19 AM.
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Old 07-22-2012, 09:57 AM   #16
MADMIKE874
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I think we should be able to simulate that as the dyno is a dynopack 5000 it is a hub based dyno. But when I rest the ECU I did not see any change.
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Old 07-22-2012, 10:02 AM   #17
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And yes I was cruising in 6th gear. From what I have read and was told from my tuner these newer 08+ cars have an issue with using cruise control as it has it's own map that you can tune in. When it threw the engine code it was the first and only time that I used the cruise after getting tuned.
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Old 07-22-2012, 10:06 AM   #18
cdoliver
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And yes I was cruising in 6th gear. From what I have read and was told from my tuner these newer 08+ cars have an issue with using cruise control as it has it's own map that you can tune in. When it threw the engine code it was the first and only time that I used the cruise after getting tuned.
I've never heard that about the cruise control. Not sure if it's true or not. I'd make sure before you leave the tuner you have them check your compression. Not trying to scare you, but just checking it off the list.
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Old 07-22-2012, 10:22 AM   #19
MADMIKE874
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Yeah the cruise would be the same as not tuning the car in all 3 driving modes "I,S,S#" because they all have there own maps to start with. But no I want all possible problems addressed so any suggestions are great. Although I don't think it is compression car only has like 20,000 miles on it and has always been great no issues. The car left the dyno great no issue. Only minor hickup while tuning was the fuel pressure line going to the intake manifold kept coming off until I put a clamp around it
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Old 07-22-2012, 11:41 AM   #20
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The cruise uses whatever mode you are in whenever you engage it. My 2011 blew a ringland at 12,000 shortly after the 20g install. Had same symptoms. I combatted heat(wrapped downpipe, uppipe, headers. Heat was not the problem. It's fuel and the different fuel system they started using in 2008. I also changed the maf sensor, the map sensor and o2 sensor to no avail. Have your tuner monitor your fuel pressure. This is a good place to start.
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Old 07-22-2012, 12:26 PM   #21
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Well I hope to God it ain't that!!! But OK I really appreciate your input once I get everything done I'll check.those other few things you mentioned.
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Old 07-22-2012, 02:05 PM   #22
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How much work is involved with switching those For?
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Old 07-22-2012, 02:05 PM   #23
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And what about cost?
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Old 07-22-2012, 02:23 PM   #24
konsept
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Originally Posted by MADMIKE874 View Post
How much work is involved with switching those For?
Quote:
Originally Posted by MADMIKE874 View Post
And what about cost?
I honestly don't know... but the cost of the Aeromotive FPR is approximately $200 after taxes in Canada.

Like I said, I'll report back my findings with it. Just hoping its not a complete waste of money.
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Old 07-22-2012, 03:31 PM   #25
MADMIKE874
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I just spoke with one of the guys from rallysport and I told him my issues and asked about the the same FPR you mentioned wanting to know if he thought that would fix it and he thinks it is some thing else. His thoughts were if it were the FPR it would have shown on the dyno tune. He said it sounds simpler than that like a leak or a hose loose. So I guess once I get it back together it do another pressure test.
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