So I bought an 03 WRX today. SEE END OF THIS POST FOR THE BOTTOM LINE The facts: Mods: TBE, bov, huge tmic, "boomba fuel rail", grimmspeed up pipe, GRIMMSPEED BCS So now I have to play the, what did I just buy game... The good: everything is new and clean. New timing belt, plugs, sensors cleaned or new, compression is perfect. The car had a tune at DB a few years ago. It sounds and feels great at speed. PROBLEMS: the boost gauge shows 5psi when I'm just cruising. Cruise control at 65mph. It will dip down a bit, but it's pretty steady. COULD BE THE GAUGE? Vac is low. -10 off throttle and about -5 at idle. Shows I'm spiking about 20psi and normally hitting about 15 during high boost, but doesn't feel that quick. I have an 05 with 235k miles that I'm trading for this that feels much quicker. PROBLEMS: my 05 has tbe and bov. It's got the v3 Cobb ap at stage 2 91 tune. It runs amazing. I plugged in the AP to the 03 to get boost reading and it maxed the boost reading at idle (525psi lol!). This is UNMARRIED. I will marry the AP to the 03 tomorrow and post my reading. BOTTOM LINE: can I run the AP stage2 map with the GRIMMSPEED BCS and other mods listed? If the boost doesn't read on the AP how can I test the boost gauge itself and boost/vac on the car quickly and/or easily? Me: tuned car driver for 12 years, very little mechanical knowledge. Thank you!
Take it easy until you get things sorted to avoid a blown engine... On the 03, do you know if the DB tune was done using an AccessPort, and I'm assuming that the seller didn't include the AP with the car? If so, when they unmarried the AP it reverts to the OEM tune which is a Bad Thing when using an 3-port ECBS!! Is the boost gauge mechanical or digital (pneumatic tube into the back of the sensor or an electronic harness)? If the latter, when you start the car turn it to On and then let the gauge initialize, instead of cranking the starter right away. If you start the car right up without letting the gauge initialize, the 'zero' will be wrong leading to the vac/boost reading getting shifted. Try what I said above and see if the readings make sense. Do you know if the fuel injectors are stock or not? The cobb stage 2 map will not work with the ECBS. You can download a map from cobb that is supposed to if your car matches the parts the map was made for, but I'm not sure if if trust it - ask @JNendza003 about his experience with it. If I was you, I'd unplug the vac lines from the ECBS and go back to the stock 2-port BCS (with the pill in the vac line) and run the normal cobb stg 2 map, or if you're not comfortable doing that then do the same thing except run a vac line from the turbo outlet nipple directly to the wastegate. This is the safest form of boost control around, it won't boost spike and will limit boost to about 7psi. Then you can figure out the boost gauge reading, make sure that the AP is showing good fuel trims and no knock. After that is sorted you can set up your choice of boost control and get the right map on their and/or get it protune. You can test the boost gauge carefully with a bike pump that has its own gauge.
Not sure that this will help at all, but when I got my AP for our car Cobb had a Stage 2+ map. Basically stage 2 mods plus a Cobb ECBS. I have a Grimmspeed ECBS and was told the map should/would see it as the same. Obviously a pro tune would be ideal, but it's been fine for me for several months.
OK so when I tried to install the AP it told me that an accessport was already being used. If I continue it will delete my previous tune and it will be unrecoverable. I called the previous owner and he does not know anything about this. He said he got the tune done in 2013 and was not aware they used an AP... But back to reality I think it is just a vacuum leak. So no matter what I do I need to track down the leak. Once I find the leak then I can either do a pro tune or use the stock BCS and run the same tune that I had on my old car which I really liked.
UPDATE: definitely a vacuum leak. That's fixed. The vacuum is normal at idle, off throttle, and cruising. The AP shows all parameters are normal. Amusing that the AP shows I peaked at 527.16pounds of boost! The tune from the prior owner was conservative, likely why the car feels a bit slower than my old car. I like the idea of a more aggressive protune.
You might be encountering the AP V3 bug where the min/max boost levels are wacked out, update the firmware and that should be fixed: https://static.cobbtuning.com/support/releasenotes/AP3-SUB-003.html
That's not it. It's the grimmspeed bcs I believe. I am lucky to currently have 2 WRX's to play with. The AP shows the correct boost in the other car.
