Flew to Florida last night to check out and eventually drive back an 03 Cobra in Satin Silver. Made a judgment call, the gauge wasn't showing boost and although I had never had a Cobra before, it felt slow. However engine checked out, compression was good, no odd noises, no smoke out the tailpipes, no leaks, underside looked good and trans felt solid with no excessive shifter slop. So I took a chance that the boost issue was a minor boost/vacuum routing issue. Used the issue to talk the guy down further in price. Drove it home 8 hours, got about 280 miles to the tank going 83mph.
Go to investigate the vacuum lines today and through an old post I see someone mentioned the two lines coming from the bottom of the blower (red hard lines) should go to boost gauge and FRPS. Go to check mine out, one was going to FPRS and the other was going to a vacuum T by the passenger firewall. There was another nearby line as well with a black (vacuum I assume) line that looks identical to the boost gauge line, hooked up to where the boost gauge should be. Those black lines were installed in each other's places, it seems. I fix the issue and holy cow it feels like it has 150 more horsepower than yesterday. The only mods it has are 2.81 upper pulley (I did not measure and verify yet), midpipe, and mufflers.
Glad I went with my gut that it would be an easy fix. Pic of the two black lines that were mixed up.
The only thought in the back of my head is how I know previous owners probably drove the car hard with this errant setup. This error would also result in the FPRS boost circuit being exposed to a vacuum line, which would be negating the boost the FPRS is supposed to see anytime the throttle is mashed, resulting in a lean condition because the FPRS wouldn't be seeing the appropriate positive pressure. There was no check engine light at any point, no lights on the dash at all (they all work). It didn't make any noises or stumble, it just accelerated slowly in this condition. Anyway, glad I found the problem and it feels like a monster now, happy to be in my first 03. Disregard how dirty the car is in the pics, have not washed it since the drive.
I strapped the phone to my steering wheel for a pull to see where the boost would go, does this look right for a 2.81 upper only? I have no reference. Pics of the car, too.
Go to investigate the vacuum lines today and through an old post I see someone mentioned the two lines coming from the bottom of the blower (red hard lines) should go to boost gauge and FRPS. Go to check mine out, one was going to FPRS and the other was going to a vacuum T by the passenger firewall. There was another nearby line as well with a black (vacuum I assume) line that looks identical to the boost gauge line, hooked up to where the boost gauge should be. Those black lines were installed in each other's places, it seems. I fix the issue and holy cow it feels like it has 150 more horsepower than yesterday. The only mods it has are 2.81 upper pulley (I did not measure and verify yet), midpipe, and mufflers.
Glad I went with my gut that it would be an easy fix. Pic of the two black lines that were mixed up.
The only thought in the back of my head is how I know previous owners probably drove the car hard with this errant setup. This error would also result in the FPRS boost circuit being exposed to a vacuum line, which would be negating the boost the FPRS is supposed to see anytime the throttle is mashed, resulting in a lean condition because the FPRS wouldn't be seeing the appropriate positive pressure. There was no check engine light at any point, no lights on the dash at all (they all work). It didn't make any noises or stumble, it just accelerated slowly in this condition. Anyway, glad I found the problem and it feels like a monster now, happy to be in my first 03. Disregard how dirty the car is in the pics, have not washed it since the drive.
I strapped the phone to my steering wheel for a pull to see where the boost would go, does this look right for a 2.81 upper only? I have no reference. Pics of the car, too.
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