P0500 and P1518

[rjrutzky]

I recently bought a Legacy GT race car, motor built and tuned by Cobb. Ran great for 8 races. I needed more power for my class so I added a 16g and an intercooler and had it tuned locally. Car didn't make any more power, so I was bummed, but it ran well on the dyno. During the first race it goes into limp mode with the P0500. I checked all my connections that could have been messed with during the install and even changed the 2 VSS sensors from my spare tranny. Now I don't know much about the motor since I bought the car fully assembled, so not sure what the old map had unchecked. All of my maps are locked, so I can't read them. I emailed my new tuner and he said it might be a ground problem. Any idea where the ground problem could be? I test drove the car after installing the parts under light boost and it had no problems. Could it be a total coincidence that the car runs great, before the new tune and after, I get a "ground problem". I've emailed Cobb in Plano that built the motor and tuned the car and no reply at all. I'm grateful for any help because I have a race in 2 weeks and if I don't show, my points lead is gone. THanks all!

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[Cobb Tuning]

Originally Posted by rjrutzky

I recently bought a Legacy GT race car, motor built and tuned by Cobb. Ran great for 8 races. I needed more power for my class so I added a 16g and an intercooler and had it tuned locally. Car didn't make any more power, so I was bummed, but it ran well on the dyno. During the first race it goes into limp mode with the P0500. I checked all my connections that could have been messed with during the install and even changed the 2 VSS sensors from my spare tranny. Now I don't know much about the motor since I bought the car fully assembled, so not sure what the old map had unchecked. All of my maps are locked, so I can't read them. I emailed my new tuner and he said it might be a ground problem. Any idea where the ground problem could be? I test drove the car after installing the parts under light boost and it had no problems. Could it be a total coincidence that the car runs great, before the new tune and after, I get a "ground problem". I've emailed Cobb in Plano that built the motor and tuned the car and no reply at all. I'm grateful for any help because I have a race in 2 weeks and if I don't show, my points lead is gone. THanks all!

What year LGT? Can you list all your mods? The 05-06 LGT (and other earlier Subarus) will throw at least those two codes (P0500 and P1518) along with 3 others when you still have the green test mode connectors connected (what you would do when you are reflashing a new map).

Bill

[rjrutzky]

Thanks Bill. It's a 2005. And I had read about the connectors, so I checked that and they are disconnected.

Not sure on the mods as Plano Cobb built the motor and they haven't responded to my email. From what I was told by the previous owner, it's a forged piston, forged rod motor. Unknown if it still has TGVs. Was bone stock save for a cobb short ram and gutted uppipe until I added the BNR 16G turbo and process west intercooler

[rjrutzky]

I should add that the p0500 doesn't automatically pop up after resetting the codes. The p1518 does, but the p0500 os random. Sometimes after a mile of driving, sometimes after several laps.

[Cobb Tuning]

I passed the details of your problem to the rest of our Subaru group. I'll see if they have any suggestions and pass them along (keep in mind that we are closed on the weekends so I may not get an immediate response).

Bill

[rjrutzky]

Originally Posted by Cobb Tuning

I passed the details of your problem to the rest of our Subaru group. I'll see if they have any suggestions and pass them along (keep in mind that we are closed on the weekends so I may not get an immediate response).

Bill

Thanks Bill. I really appreciate Cobb having you keep an eye on this thread and give so much advice. I'm gonna scour through the wiring today to see if I see anything out of place.

[Cobb Tuning]

Originally Posted by rjrutzky

Thanks Bill. I really appreciate Cobb having you keep an eye on this thread and give so much advice. I'm gonna scour through the wiring today to see if I see anything out of place.

One of our calibrators suggested checking the trans-to-firewall or trans/starter-to-battery grounds.

Bill

[Cobb Tuning]

PM sent.

Bill