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Old 05-12-2009, 10:31 PM   #1
dvsone775
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Default VF39/Cobb AP Setup and Problems

Just recently I finished upgrading/rebuilding my 2004 WRX with a VF39 setup. Other modifications include: STi TMIC+Injectors, APS Turbo inlet, TBE, Up-pipe, Koyo radiator, Cobb intake, 255 Walbro, Perrin LWC pulley, ACT 13.9 lb. flywheel, ACT heavy modified pressure plate+clutch, polished ports and heads, all exhaust pipes wrapped (including turbo, UP,DP), and ppg 1-4 gears. I also went ahead and replaced my valve guide seals, water pump, all belts+idler pulleys, fuel filter, and NGK plugs (gaps checked). I am also running for the moment, the Cobb OTS VF39 Map (until I have time to get a pro-tune).

At idle, the wideband AFR registers 14.6-14.9. Revving at a standstill to 6500 RPMs, the wideband registers between 12-14. At cruising speeds in any gear and at any RPM range under 4K RPMs, the wideband registers between 14-15. The car feels fine when driving "normally" without going WOT. I'm also at 4750 ft.

The problem occurs when at WOT at 4800 RPMs (consistently), the car begins to "sputter" very rapidly; very much like the car is NOT getting enough fuel. The AP registers 17 psi of max boost (and boost comes on around 4100 RPMs) and the wideband will register 11-13. The car will continue to "sputter" at WOT above 4800 RPMs. The CEL will flash and AP will give me codes that BANK 1 is running lean and cylinders 2+4 are misfiring. I know my description of the problem is quite generalized and lacking in specific numbers and data but I have no way of data logging. I can give more numbers and data if needed but it'll be limited as to what the AP can obtain. For the moment, what could be causing the problem at WOT and above 4800 RPMs?
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Last edited by dvsone775; 05-13-2009 at 11:13 AM. Reason: missing text
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Old 05-13-2009, 12:59 PM   #2
dvsone775
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*bump*
I know how conservative, unreliable (?), and how people frown upon these OTS maps, but I'm suspecting perhaps it's the base map that may be causing the problem?
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Old 05-13-2009, 01:02 PM   #3
SYBugeye
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get rid of the ap map and get a custom tune it will solve all your problems
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Old 05-13-2009, 01:10 PM   #4
jcbluescooby
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yeh with all those mods you should be doing a custom tune..not an OTS map
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Old 05-13-2009, 01:26 PM   #5
dvsone775
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Thank you very much. I figured as much and I am fully aware that I am in dire NEED of a pro-tune. I just don't know if the symptoms are indicative of a mechanical problem or a tuning/map problem. If it isn't the latter, then I would not be sure what the culprit of the problems may be.....otherwise, I will be looking for a reputable tuner somewhere in the Bay Area (or vicinity of Sacramento).

Any suggestions/recommendations for a tuner? or perhaps another problem?
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Old 05-13-2009, 01:46 PM   #6
SYBugeye
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i just personally think the OTS maps are junk compared to a custom/pro-tune since. I just dont think they count for variables that occur with the car, every car is didnt and unique in its own way but remember that is just my opinion..

But it sounds like the OTS just cant get wrapped around something thus causing problems over 4800 rpms
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Old 05-13-2009, 01:52 PM   #7
zulater
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I was running that map on the exact mods required and I had lots of knock. My tuner was going to do a before/after road dyno but he did not want to run the car because of the knock. Get a protune asap and do not let it see much boost.
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Old 05-13-2009, 02:07 PM   #8
dvsone775
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I AM going to GET a pro-tune BUT what I am asking pertains to the fact that if the problem is coming from the map, then a tune will fix it; otherwise, getting a tune where the problem continues to persist will negate the time and cost of getting a tune--I'm just trying to get the car dialed in and problems solved prior to spending the money and time to get a pro-tune. Thanks again.
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Old 05-13-2009, 02:22 PM   #9
zulater
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Quote:
Originally Posted by dvsone775 View Post
I AM going to GET a pro-tune BUT what I am asking pertains to the fact that if the problem is coming from the map, then a tune will fix it; otherwise, getting a tune where the problem continues to persist will negate the time and cost of getting a tune--I'm just trying to get the car dialed in and problems solved prior to spending the money and time to get a pro-tune. Thanks again.
More than likely yes the map is the problem. Can you log the car and see the knock count? Changed fuel filter with the new pump? Reuse stock sock on the pump?
It could be something with fuel but you're able to flow more air with the intake, ported heads and the TGV deletes so you could just be running lean from that as well.
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Old 05-13-2009, 02:28 PM   #10
dvsone775
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I used the new sock that came with the new pump. And the heads were never ported--just polished throughout (combustion chamber on head and intake+exhaust ports). My buddy doesn't have a flowbench so I only asked the head and ports to be polished--don't know if it makes a difference but he did it out of kindness (and it was free). I am currently and temporarily using the AP VF39 base map. I don't know if it has the capability of logging anything that comprehensive. Any other suggestions or perhaps I should try running an AP map that someone has made that could possibly be more superior than the Cobb's?

Last edited by dvsone775; 05-13-2009 at 02:30 PM. Reason: missing text
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Old 05-13-2009, 02:39 PM   #11
SYBugeye
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you can try that but to be on the safe side have them downlaod your map so if it doesnt work you can change it back
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Old 05-13-2009, 05:50 PM   #12
SlouWRX
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You can log using a lap top and the AP v2......its free, u download the software at Cobb's website.
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Old 05-13-2009, 07:58 PM   #13
dvsone775
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I just checked their site and it appears that my dongle and AP needs updating. I'll update it immediately and hopefully I'll get some data logs up this evening. Thanks again.
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Old 05-13-2009, 08:11 PM   #14
spinningcain
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Clean your MAF
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Old 06-12-2009, 10:43 PM   #15
dvsone775
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A friend of mine just suggested to lessen the gap on my plugs (perhaps to increase spark?) to solve the misfire/detonation at high RPMs (however, the problem consistently appears at over 5K rpms or boosting above 15-16 psi); rapid sputtering (WG?) is audible from the cockpit. What I've done so far to diagnose the problem but to no avail are:
Plug gaps (I also swapped the plugs from the misfired cylinders with the cylinders that were not misfiring--but I still get misfire in 2+4), coil packs, vacuum/boost, MAF, O2 sensors, fuel system

I'm waiting for a 3-port solenoid to come in and have that installed and tuned to see if this may fix the problem. But, in the mean time, does anyone have any opinions or more knowledgeable facts as to how lessening the gap may fix the problem (misfire or detonation---I can't tell the the difference when I'm driving); I just don't see the relation with lessening the gaps when the misfire is consistent in cylinders 2+4 (regardless of whether I swap the plugs in as many combinations as I can).

Thanks,
J

Last edited by dvsone775; 06-13-2009 at 03:13 AM.
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