I have a 2003 Mazda Protege 5 that is coding out P0090. That is the Fuel Pressure Regulator Control Circuit. In the last year I have replaced the fuel pump in the tank, installed a new ECM, fuel relay, and all the fuel pressure regulators on the common rail. It still codes out the same code. My mechanic says the fuse box got overheated and he repaired the portion that got hot. Could this be the source of the continuing problem? Does anyone have any ideas of what it could be? I'm planning as a last resort, to take it to a Mazda dealership for diagnosis.
2nd issue: I installed a set of headers without a primary cat. I'm getting a code P0421, Warm Up Catalyst Efficiency Below Threshold. What are my options? Can I get the ECM reprogrammed to think it has 2 cats or can I just install another cat downstream of the headers and hook up both oxygen sensors.
I love the car, but the fuel pressure problem has been going on for almost a year and a half.
Frustrated in Texas.
2nd issue: I installed a set of headers without a primary cat. I'm getting a code P0421, Warm Up Catalyst Efficiency Below Threshold. What are my options? Can I get the ECM reprogrammed to think it has 2 cats or can I just install another cat downstream of the headers and hook up both oxygen sensors.
I love the car, but the fuel pressure problem has been going on for almost a year and a half.
Frustrated in Texas.
