Will not stay running, possible fuel pump issue

I should have said that I drove the car to a friend's house, shut it off and when I went to leave the car would start and shut off. So tried to figure it out then had it towed to my house. Then I got a new fuel filter to put on. Then I got a new crankshaft sensor to put on. Then I got a new fuel pump and put that in and nothing, it did not not change a thing. Still the same as when it first started not running.

Hi,

When you jump the relay, will the vehicle continue running? If so and you checked the relay, we need to go backward to the main relay in the under-hood fuse block.

I attached the schematic below showing how power goes from the main relay to the fuel pump relay. Check to make sure it is good as well as the engine CNTL 3 fuse in the under-hood box. When checking the fuse, also make sure there is power to and from it. Here are two links you may find helpful when testing the fuses and the relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Let me know what you find or if you have questions.

Take care,

Joe

See pics below.

Okay, jump the fuel pump relay and try starting the car and it does the same thing starts then shuts off. So, if the pump is running it won't start or so it is not a fuel pump problem. And I checked the main relay and the engine CNTL fuse all good.

So, if it isn't the fuel pump what is not letting it run. I don't know what to check?

Hi,

It could be a couple of things. Next, we need to confirm the fuel pressure is within the manufacturer's specs. Here is a link that explains how it's done:

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

If you look at the attachment, it provides the manufacturer's fuel pressure specifications.

The reason I'm suggesting this is because it starts and then stalls. The pressure may build enough to first start the engine but be unable to maintain it.

Let me know what you find. Also, if you don't have a fuel pressure gauge, most parts stores will lend one to you.

Take care,

Joe

See pic below.

Do you think it is ECM malfunction how do you check the ECM.? I have had negative off the battery for a bit and that didn't do anything. I have a code reader but there are no codes. I am at a loss. Thank you for your time.

Hi,

Anything is possible but chances are that isn't the issue. I suspect it is a fuel pressure issue.

Are you comfortable testing the pressure using the link I provided?

Let me know.

Joe

Okay, with the key on it goes to 35PSI. So, it should have at least 45PSI. But I just put a new pump in it.

So, does that mean the fuel pressure regulator is bad?

Hi,

If the regulator is bad, chances are the pressure would be high. However, if a fuel injector is leaking, it will lower pressure. Do me a favor. Try starting it and then shortly after, remove one spark plug at a time to see if any are wet.

Also, when you check fuel pressure, did it drop off quickly when the key was released?

Let me know. Also, record it cranking and upload it so I can hear it.

Take care,

Joe

On this V6, the spark plugs are under the intake and coil pack over spark plugs. So it would be hard to pull plugs one at a time.

Also, the pressure dropped off right away.

If it drops off that quick, there is a leak. If there is no evidence of a fuel leak that can be seen or smelled, the injector or injectors are likely leaking.

Sorry about that. I forgot the intake needs to be removed. Also, I had an afterthought. If you remove the fuel pressure regulator vacuum hose and turn the key on, does any fuel come out of the vacuum connector location on the regulator?

I attached all the diagnostics below for fuel-related issues. Take a look through them and see if there is anything you feel may help. Based on what you told me, there has to be a leak at some point. Otherwise, it would hold pressure for at least five minutes before starting to drop.

Let me know.

Joe

See pics below.

I am trying to send you a video so you can listen to it when I start the car. But I'm not sure how to do that.

You should be able to make the video using a cellphone and then upload it to your computer or send it from your phone. I'm not the greatest with phones, but I know it can be done.

Let me know if you can figure it out and I will see what I can find.

Joe

Sorry sent the wrong thing, but I am getting close.

Car starting.

Hi,

Is it starting now and continuing to run? Let me know.

Joe

Nope, still doing the same thing. I have not got anywhere with it. I guess I need to go after injectors?

Hi,

I need you to recheck for an RPM signal when cranking. When you first turn the key on, the fuel pump primes. When cranking, if there is no crankshaft signal, the PCM will not turn the fuel pump back on.

Let me know.

Joe

Yes, I put a new crankshaft sensor in it and it didn't change anything..

Are you getting spark to the plugs or an RPM signal when cranking the engine?

Let me know.

Joe

How do I check for that? I think since it starts that it's getting fire at the plugs.

Can a Knox sensor shut down the fuel? A friend of mine told me a Knox sensor made his car not get fuel just like mine. But I thought it would throw a code for that?

Hi,

The Knox sensor would set a code and you would likely hear excessive noise from the valves. The Knox sensor system enables the control module to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. In essence, it changes ignition timing to meet the needs in the best possible way.

I'm not sure what kind of vehicle he has, but I've never seen the sensor shut fuel down.

Let me know.

Joe

You asked me if I was getting spark at the plugs when it is cranking. Well, I was thinking that since it starts then shuts off that is getting spark or is that not what you mean. When I am turning it over my tachometer does not move until it starts..

Hi,

Yes, that is what I meant. But I'm questioning if spark or fuel is lost when it first starts and then stalls.

You mentioned that the tachometer doesn't move until it starts. Does it drop to 0 right before it stalls?

Let me know.

Joe

Well, it doesn't move until it starts, and it shuts off right away. It doesn't run long enough to tell. So, it goes up and back to 0 can't really tell. But if it was what would that mean?

Hi,

Often times if there is an issue with the crankshaft position sensor circuit, the RPM signal is lost. If you could get your hands on a live data scan tool, we could check to see if it drops. Also, if you can record it and upload what you are seeing, it may help me.

Let me know.

Joe