2002 4.6 crank no start

[Stevo1111]

Hi All,

I'm new here. Picked up an 02' 4.6 with 100K miles for a such a good price I couldn't pass on it.

Ran strong until I parked it yesterday. I filled up the washer fluid and it all ran out right under the passenger side door. I only mention this because it seems like its right near the ECU.

Started last night, ran for about 1 second, then died. After that, crank no start.

Checked fuel pump relay, switched out with one I know is good, jumped pins 87 and 30. Nothing.

Checked fuel pressure. Had some fuel in the rail which came out, but 0 psi under key, 0 psi at crank.

Connected a scan gauge, but was unable to pull any codes although it did seem to connect.

When keyed on, the fuel pump will run for about 0.5 seconds, go "coooo", and then nothing. No sound.

All points lead to a bad fuel pump, but before I drop the tank, any way to verify if its a bad ECU?

Thanks!

Steve

 

[Bedrck47]

So far you now know why you got it at a good price Now get ready to get a loan at the bank.

Get a can of starter fluid and have someone crank the engine while you spray JUSY A LITTLE INTO THE THROTTLE BODY JUST A LITTLE

Let us know if it tries to run

 

[Bedrck47]

You most likely need a new fuel pump But do the starter fluid test

 

[Bedrck47]

Did you test the fuses?

What was the voltage at pin 30 of the fuel pump relay?

Have you replaced the fuel filter?

 

[Bedrck47]

It is not unusual for the fuel pump to shut off if the engine does not start

 

[docraymund]

A definite way to tell is to pull it out, if a burnt odor is noticed, open it up and check for burned capacitors. Just follow static electricity precautions when handling the ecu.

 

[stamp11127]

Right.... 0 psi on the fuel rail so let's take a look at the ecu internals.

How about checking for voltage on the fuel pump relay connector for pin 30 first. If voltage is present then jumper 30 to 87 and read fuel pressure again. If no pressure drop the tank and check for voltage going into the pump. If voltage is present then either the ground or the pump is bad.

My rule of thumb is at about 100,000 to 150,000 miles start getting ready to swap in a new one.

 

[Stevo1111]

Thanks for the replies so far!

Forgot to mentioned, I jumped from 30 to 87 earlier also, still just cranked.

I will test the voltage from 30 to ground to make sure the ECU is supplying a signal. That could be a way to tell for sure if the ECU is at least partially functioning, I suppose.

Can you pull a signal from near the pump without dropping the tank? Is there a connector back in there that I can squirrel myself to?

 

[stamp11127]

The ecu/pcm controls the control side of the relay, 30 should be hot at all times. I've read where the harness may be accessible from the wheel well but haven't verified it.

 

[Pappy]

When I did my fuel pump, I have an '02 5.4 XLT 2WD, I dropped the tank, but I learned that the plug to the fuel pump is accessible with the tank still in, IF, you jack up the back end, support it with jack stands and let the rear axle hang on the shocks. It is kinda like a contortionist circus act - but it can be done.