Codes PO 191 and PO 191, crank but no start?

Hi,

We need to focus on the fuel rail code. A pending code is a little different. Pending codes are typically generated when the vehicle's onboard systems detect a potential issue or anomaly but have not yet confirmed it as a persistent problem. They act as early warning signals for potential malfunctions that may develop into permanent trouble codes if the problem persists over a certain number of drive cycles.

The pending code, in this case, has become an active one already.

As far as the code, P0191, it can be caused by a few things. The sensor could be failing, there could be a fuel pressure issue, an engine vacuum leak can cause it or even low fuel.

When the vehicle is running, does it have a smooth idle? You mentioned it sits more than driven. Has it been a long time since it was driven?

Let's do a couple basic checks. First, the sensor is located on the fuel rail. There will be a vacuum hose going to it. Check the line to make sure it is good and not cracked or disconnected. See pic 1

Next, check for engine vacuum leaks.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know what you find. Also, when you check the vacuum hose at the sensor, make sure there is no evidence of fuel getting into it.

Take care,

Joe

See pic below.

Thank you for the reply.
The car has been sitting for a few months and is started every few weeks.

But now it doesn’t start. It only runs for a few seconds when starting fluid is sprayed in the air box hose.

I will check the regulator and hoses and will report back. Thank you

Hi,

If it starts with starting fluid and then stalls, it isn't getting fuel. The first thing we need to check is fuel pressure. I have a feeling there is low or no pressure and that is what is setting the code. If that isn't the case, we will need to trace injector wiring which isn't difficult.

First, we need to check the fuel pressure.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/radiator-pressure-test

You will need a fuel pressure gauge for this. If you don't have one, most parts stores will lend one to you.

Try this and let me know the results.

Take care,

Joe

See pic below for the manufacturer's fuel pressure specifications.

Hi Joe,

Thanks for the reply, but the link you sent me is for radiator pressure testing, not fuel pressure testing.
Can you send the other one? Thank you

OMG!!! LOL Sorry about that.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let me know if that helps.

Take care,

Joe

Hi Joe, would you be able to provide me with the correct procedure to replace the fuel pump/sending unit assembly? (I will be doing this on my driveway)

Thanks!

Hi,

If you are doing this at home, you will need to lift the rear of the vehicle a bit. Make sure you use good safety stands to support the vehicle.

Also, you will need a floor jack because the tank is heavy, especially if there is fuel in it. You don't want it to fall. If you use a floor jack to support and lower the tank, place something like a 2x6 between the jack to prevent damage to the tank.

If you look below, I attached the directions. Basically, the majority of the directions are the removal of the tank. I placed them first.

Let me know if this helps or if you have other questions.

Take care,

Joe

See pics below.