1998 Mercury Mystique Repair Question
Mileage: 196,000 miles.
Mercury Mystique Engine Problem
Asked by RMcPhersonAnswer
Do you have any codes in the computer?
That fuel pressure drop could cause the the fuel lines to bleed down all the fuel and cause excessive cranking and start time.Try this in the morning before starting it.Turn the key to the run position wait about 3 four seconds then turn it off then repeat do that about 5 times then start the car.Does it start better?
I cycled the ignition switch 6 times allowing the fuel pump to pressurize each time then tried to start the car but it had no appreciable affect on accelerating the engine start time. As I press and depress the accelerator pedal I do get some backfire through the air intake at sporadic times.
Do you have a scan tool that can read live engine data?The next thing i would be looking at was coolant temp sensor reading when your starting it cold?You could have a bad coolant temp sensor.
I have an CAN OBD2/EOBD scan tool but not one that will read live engine data that I am aware of. However, I had previously purchased a coolant temp sensor but had not installed it but went ahead and installed it. However, it did not make any difference regarding the cold start problem.
Just because you a new sensor doesnt mean its reading correct thats why i asked to read the coolant on the scan tool.Which engine do you have?
please do the trouble shooting i posted.
Regarding the trouble shooting tests:
1. Everything checks out ok.
2. Fuel Pressure at idle = 32PSI; @ 2500 RPM = 32PSI (Spec is 27.5 to 33.5 w/Vaccum connected) (There is about a 6 PSI rise when I step on the accelerator quickly.)
3. Engine off cycle 4 times fuel pump pressure = 38 - 40 PSI;
Fuel Pressure drop with engine off after 1 minute = 12 PSI.
Recommends checking the Pressure Regulator and Fuel Injectors for leakage. The Pressure Regulator is new and there is no leakage from it. I do not know how to test the Fuel Injectors for leakage?
Thank You