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Old 02-03-2013, 02:31 AM   #1
chrisfromalbany
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Default Engine won't stop misfiring boost

Friend has problem with 03' WRX. Any ideas on most likely issue with car?

Thanks,


Its a 2003 wrx, mostly stock but has a 3 inch turbo back exhaust, spt intake and a cobb ap running stock tune... Im running lean and keep getting misfires at higher rpm band... Not sure why. So its sitting untill i can get a compression test and a leakdown test...


Yeah only under boost and its differnet cylinders each time... Ive had to replace the turbo 4 times, fuel pump and the fuel regulator and spark plugs... Both o2 sensors replaced at the same time... So yeah im out of ideas. Could be a plugged pre cat but i have to wait for a compression test and leak down test to make sure its not a compression issue. Ask your tunner if he knows freds auto from fort edward. Fred was tellin me he knows a tunner... I dont remeber his name. But im kinda saving money in case i need a new long block. So its sitting right now untill i can make funds. Still drives and all but i get this crazy idlic hesitation when im on the high way going from slight vac to slight boost. Then it takes off like the spaceshuttle. Lol.

Yeah multiple misfires i have a code reader... Not sure what to do so i figured comp and leak test should show if engine ok.
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Old 02-03-2013, 05:51 AM   #2
TropicalReefer
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This is pretty confusing. Why is he running a stock tune and not stage 2? Why has the turbo gone out four times? And how on earth does he still have a catted up pipe after replacing the turbo four times?
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Old 02-03-2013, 09:45 AM   #3
chrisfromalbany
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Quote:
Originally Posted by TropicalReefer View Post
This is pretty confusing. Why is he running a stock tune and not stage 2? Why has the turbo gone out four times? And how on earth does he still have a catted up pipe after replacing the turbo four times?
think he backed out the stage 2 to stock to try resolve the misfire issue.
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Old 02-03-2013, 11:02 AM   #4
Dakota D
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chris if your buddy has the stock intake have him put that back on and flash to cobb stage 2 stock intake and if that helps at all.^_^
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Old 02-03-2013, 12:17 PM   #5
quazimoto
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Old 02-03-2013, 01:51 PM   #6
Tweeder
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Get a tune!! Your running every part for stage 2. The CAI alone requires a tune on our cars because they make us go lean. Get that done first or go back to stock.
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Old 02-04-2013, 05:50 PM   #7
t-rex03
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Hey guys, i'm the guy Chris was talking about. Ive been meaning to put a post up here if the compression test came back with anything insignificant, which it did. cylinder psi is 140, 130, 130, 135 so looks ok compression wise...

why i replaced the turbo 4 times is a long story. When i bought the car it had a dead turbo in it as well as a huge list of other big issues, i knew that so i replaced it with a used vf39 that had 110k miles on it and it blew the bearing in 2 weeks, second one my mechanic bought a brand new td05-h off of Ebay and that lasted a week and failed much the same way as the vf39 with the bearing failing and the impeller hitting on the side of the housing. the last turbo has lasted the longest being the oem wrx turbo with about 85k on it. as of current it is still spinning and has no shaft play. so i guess it was just a bad line of used turbos.

i also had to replace the fuel pressure regulator and the fuel pump due to bucking at higher boost. too much boost would cause it to buck hesitate and stall. hooked a fuel pressure gauge up to it and saw pressure would drop as the boost increased.

recently i got a Cobb AP to flash the stock tune to the ecu. i wasn't sure what tune was on it from the previous owner so i flashed it to stock for troubleshooting purposes. still having the same issues with the misfiring and hesitation going from vac to boost on the highway. i ran a few data logs and had bill from Cobb tuning take a look and he said the fuel trims are "borderline extreme fuel trims". so i am slightly worried about running a stage 2 if I'm running lean already, I'm not sure if the stage 2 to is designed to compensate for that or not.

I'm going to order a new cat less up pipe and a wide band o2 next pay check and run a few more data logs.
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Old 02-04-2013, 05:57 PM   #8
t-rex03
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Quote:
Originally Posted by Dakota D View Post
chris if your buddy has the stock intake have him put that back on and flash to cobb stage 2 stock intake and if that helps at all.^_^
Wish i had the stock intake Dakota D, but only have the spt intake that came with the car. I'm curious if this is affecting the condition as well.
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Old 02-22-2013, 04:30 PM   #9
t-rex03
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hey guys just wanted to post an update. so i figured out why it was misfiring, the connector for coil pack on cylinder one fractured leaving an intermittent connection. it happened while i was doing stage one reflash and data log. but the fun doesn't stop there. it is still running really lean before hitting boost. with each step in stages the lean condition gets progressively worse. i just got the stock intake from a buddy, and this weekend I am going to install it and test it out.

i also found out the hard way that the car is already running a cat-less up pipe, so no issue there.

any ideas why im running crazy lean before i hit boost?
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Old 02-22-2013, 10:56 PM   #10
zandander
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I believe its the aftermarket intake. Need to get tuned for it or go back to stock..
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Old 02-22-2013, 11:34 PM   #11
wrx1392
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put the stock air box on with a k&n filter ,and put the stage two cobb in.i had the old ECu reflash before cobb came out with the AP i had just a catless up and down pipe and a axle back and the car ran fine for 200,000 miles the stock turbo leaked a bit of oil from time to time but still works. hope you get it fixed .be sure to report back what you come up with.
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Old 02-28-2013, 04:30 PM   #12
t-rex03
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hey guys just wanted to post an update:

so got the oem intake installed and have stage 2 loaded on the ecu, still no dice. Over all the boost is much smoother and quickly reaches target psi. but when accelerating right at the cross over from vac to boost it hesitates and almost stalls out, then takes off as if it had no problem. looking at the AFR whist accelerating shows its running way lean before boost and after boost, but during boost its fine in the 13ish area. sometimes it will go past 20+ AFR when in vac.. kinda hard to explain so i included some data logs.
The first one was sitting in the drive way just revving it a bit, the other 2 are road logs. i can read the logs, but i dont have super experience like most of you guys on here.

https://docs.google.com/file/d/0B8wX...it?usp=sharing
https://docs.google.com/file/d/0B8wX...it?usp=sharing
https://docs.google.com/file/d/0B8wX...it?usp=sharing
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Old 03-01-2013, 03:59 PM   #13
t-rex03
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Anyone?
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Old 03-02-2013, 03:46 AM   #14
dollar5th
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13 is lean in boost
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Old 03-02-2013, 03:57 AM   #15
TwoFifty
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I can't read the logs because I don't have a program to view them but how were you driving when you recorded the data logs? Did you follows Cobb's procedure?

The only reason I ask is because there is a certain way to record data logs so that the data in the table is actually use able. If you haven't done it that way then the data might not really tell us very much, for example sitting in the driveway revving the car isn't going to really give us any use able information to help you with the way your car is running.

When was the last time you did a boost leak test? Have you done your compression test yet? Have you done a vacuum leak test yet?

Is the vehicle running a factory BPV or does it have an aftermarket BOV on it?
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Old 03-02-2013, 04:26 AM   #16
tersplat
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I was going to say, 13ish during boost is EXTREMELY lean. Are you running stock injectors? if so, is the tune you are running for the stock injectors? I', new to WRX's so I don't know a lot, but I do know 13 is not safe in boost. should be between 10 and 11.5 max
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Old 03-02-2013, 04:42 AM   #17
TwoFifty
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Quote:
Originally Posted by tersplat View Post
I was going to say, 13ish during boost is EXTREMELY lean. Are you running stock injectors? if so, is the tune you are running for the stock injectors? I', new to WRX's so I don't know a lot, but I do know 13 is not safe in boost. should be between 10 and 11.5 max
Actually this is a very good point, now that I re read the actual owner of the cars post.

You say you swapped a vf39 into it at some point, i'm assuming you were not running the stock injectors when you had this turbo? Did you swap them out for STI pinks or similar? If you did, when you swapped turbos again back to the oem td04 did you swap the injectors back? Because I'm fairly sure having those bigger injectors in there, even though they are only a little bigger would still cause some very bad running car without the correct tune.
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Old 03-02-2013, 10:44 AM   #18
t-rex03
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Its running the stock injectors. I wanted to upgrade them but never got around to it.
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Old 03-05-2013, 01:11 AM   #19
t-rex03
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Quote:
Originally Posted by TwoFifty View Post
I can't read the logs because I don't have a program to view them but how were you driving when you recorded the data logs? Did you follows Cobb's procedure?

The only reason I ask is because there is a certain way to record data logs so that the data in the table is actually use able. If you haven't done it that way then the data might not really tell us very much, for example sitting in the driveway revving the car isn't going to really give us any use able information to help you with the way your car is running.

When was the last time you did a boost leak test? Have you done your compression test yet? Have you done a vacuum leak test yet?

Is the vehicle running a factory BPV or does it have an aftermarket BOV on it?
Well the first log was a rev in the driveway just posted it because it showed some knock, and the other 2 were 3rd gear pulls based on cobbs recommendation for data logging.
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Old 03-05-2013, 01:32 AM   #20
dollar5th
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Are you looking at the front o2 sensor or a wideband for your AFR's?
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Old 03-05-2013, 01:46 AM   #21
t-rex03
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howdy,

have a rather large update, and a thanks to all for helping me with this crazy issue.

so i recently found out though my mechanic that its not running the stock turbo, but in fact it is a vf24. at first looking at the turbo it has in big letters on the side of it IHI Turbo which i thought was the stock unit. so im probably maxing out the fuel pump and injectors which im now planning to upgrade in the near future.

last Saturday after getting the stock air intake from a friend and still having the same issue he suggested i get it pro tuned to rule out it being a tuning issue. in about an hour with the tuner, he found that not only was i running crazy lean but the new aftermarket o2 sensor was throwing the afr readings all over the place. he even tuned out the maf sensor to diagnose the problem to no avail. we decided to replace the sensor before doing any further tuning so as not to run in circles. so i got a new oem front o2 sensor on order from the dealer. i did though have the original front o2 sensor that came with the car when i bought it, i saved it because i wasn't sure if it was bad or not and i think i had replaced it to try to diagnose the problem on my own. so i put the old o2 sensor back in and flashed it to stock. no issues, no hesitation or almost stalling. so i tried stage 1 and 2 with the ap stock maps and i have the same results as the stock map. it seems to be cured! the afr is stable and boosting to 12 psi the afr is pegged at 11.2 . looking at both o2 sensors they are both made by Denso, but the aftermarket one part number is way off, they both look physically identical, wire coloring and all. i did a comprehensive search on the aftermarket o2 sensors but haven't found much forum wise. My tuner told me it is pretty common issue with wrx's and sti's and its a very common thing to run in to while tuning.

any one else run into this issue?
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Old 03-05-2013, 01:52 AM   #22
t-rex03
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Quote:
Originally Posted by dollar5th View Post
Are you looking at the front o2 sensor or a wideband for your AFR's?
The tuner had a up the tailpipe o2 wide band sensor, but mostly ive been going by the ap.
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Old 03-05-2013, 02:16 AM   #23
dollar5th
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Everyone should have a wideband installed with a guage, the access port is looking at the front o2 which is a wideband but due to the pressure cannot read accurately while under boost. This being said, I can believe you were seeing 13 afr in boost. This is why it is necessary to have a wideband in the downpipe. Also whenever modifying a car or buying a car thats been worked on outside of a dealer. Put time in researching exactly what is on the car, both are great ways to prevent having to build engines.
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