03 Cobra Falls On Face When Boosted

Discussion in 'SVT Tech Forum' started by keroseneburner, Apr 3, 2017.

  1. This is going to be a heck of a first post but here goes. I recently rebuilt the engine in my 03 cobra, I went with MMR 18cc pistons but otherwise stock internals. From day 1 it ran ok, didn't make as much power as it used to, as soon as it get hot (normal operating temp) it started to lose power. If you press the accelerator enough to get the boost up, it falls on it's face. I found a small vacuum leak and repaired it, no change. while it was apart I stock piled fun parts jlt cai, sct 2600maf, accufab tb and plenum, ford 60lb injectors, 2.81 sc pulley and kennebell boost a pump, an sct x4 tuner pre tuned for these mods and recently installed them hoping the tune would fix the issue. No luck. It finally threw a code the other day P0174 bank 2 lean. I replaced all the coils also when this started. Now I loaded the x4 tune on the pcm and was trying to datalog to get more info when the x4 bricked on me (not a huge fan of sct at this moment) So the brand spanking new x4 is back at sct for an unknown amount of time getting repaired. I do have an actron scanner that can datalog some pids. I am at loss as to where or what to check next.
    thanks for reading my wall of text!
  2. I'm not much help other than with a boosted car, there is no way I would be running a canned tune. Find a reputable tuner and schedule a dyno appt to get it dialed in correctly.
  3. That is my final plan, my local tuner's shop burned to the ground and they are not up and running yet. I had this problem with the factory setup and tune and the mods and canned tune. I was just trying to get it running decently so when they get their new shop we can put it on the dyno.
  4. I would honestly go back to all the basics I would check your spark plug gapping make sure that is correct for your current build also check for fuel fouling and lean staining. Do you see full boost? May have a leak in the intake system or the vacuum lines are not routed correctly. What are your long term fuel trims for both banks. The 02 sensors may read lean but the 02 sensors only see 02 so a misfire will allow fuel and air to bypass combustion. And these cars are crap at setting codes. I had to diag misfires on this vehicle before with no codes.
  5. It was like the steering wheel in the pirates lap....it drove me nuts. I finally found that my intercooler pump had quit working. That explained why it ran fine while cool but when hot it ran like crap. The computer would pull the timing out when all that hot air was entering the engine. Fixed the intercooler, the back end tried to pass the front end with all of the additional power :) I never even thought of the intercooler system, heck I even resealed the intake manifold looking for a vacuum leak.
  6. I just fixed that same issues. IAT2 was sitting at 185° on a 80° day. Sucks that my $300 tuner cant read what my $5 app and $10 obd reader can.
  7. This is my first vehicle with a air to water intercooler, I didn't even think about it. Maybe this can help someone else with the same problem.