How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Ron Your Own Question
Ron, ASE Certified Technician
Category: Mercury
Satisfied Customers: 35610
Experience:  ASE Certs and Ford Certs
Type Your Mercury Question Here...
Ron is online now
A new question is answered every 9 seconds

My name is ***** *****. I have a 2000 sable with the 24v

Customer Question

Hi my name is ***** *****. I have a 2000 sable with the 24v dohc engine .Now always but sometimes it won't start. The engine will crank . I can crank it several times. as long as I don't turn the key to off it won't start. If I turn it to off it will start and run. Many times it will run fine. twice it has stalled when backing up and the same cranking thing happens. It has a code p0191
JA: Thanks. Can you give me any more details about your issue?
Customer: what details do you need?
JA: OK got it. Last thing — Mercury Mechanics generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: Mercury
Expert:  Ron replied 1 year ago.
Hello and thank you for your question,The code P0191 indicates you have a fuel pressure concern usually meaning the fuel pump is slow to prime. Will it start and stay running if you cycle the key off and on a few time before you try starting it?
Customer: replied 1 year ago.
Hi , I haven't tried cycling the key without starting it. If I turn the key off then on it will start and run.
Customer: replied 1 year ago.
Today it is running fine.
Expert:  Ron replied 1 year ago.
The common cause for this type of problem is in most cases caused by the fuel pump loosing its prime, the fuel pump has a built in one way check valve that allows the pump to hold pressure on the first turn of the key so the car can start and when they fail it take a few cycles to get the correct pressure to start the engine. You can usually check this by cycling the key of and on a few time before you crank the engine , if it then starts the problem is usually a failing fuel pump and replacement is needed. I have also enclosed the complete testing steps if you want to test it to verify before replacing it. Copy and paste the link to your browser to open and view it. Post back if you have more questions and or need more help.
Customer: replied 1 year ago.
Thanks , sounds like you are leaning toward the pump. There is a pressure reg on the fuel rail , then a short hose to a round diaphragm. could there be a problem there? I am changing the fuel filter also and swapping the relay with the one next to it.
Expert:  Ron replied 1 year ago.
Yes the regulator simply regulates the running pressure and if the pump is slow to prime the regulator can not regulate the pressure. This dose sound like a failing fuel pump which is the most common cause and will also cause the fuel pressure code P0191 to set. Running the test steps will verify this as well.
Customer: replied 1 year ago.
Thanks Ron, I don't have a gauge. I will have to get one. I am a old muscle car guy. Was that yes to pressure reg could be the problem? there is junk yard near by that has one sitting that I could get those 2 parts from . tank is 3/4 full .
Expert:  Ron replied 1 year ago.
Its not likely the regulator is going to be a problem, it most likely the fuel pump loosing its prime which is very common on the 2000. Cycling the key a few time when it will not start is a pretty good test as well. If it starts after cycling the key a few time your looking at a bad fuel pump.