Dear Fellas,

I have a new issue now, I had code 45 before but that got sorted with my new injectors, new O2 sensor new map sensor, and generally all sensors, but now I have a Code 44.

According to Haynes book, It means I have a lean exhaust, previously it was rich now it is lean... Strange. However my fuel pump makes a strange noise now, like a turbine or something else would be in my tank, actualy its 3x louder then my engine, it is a new pump actually, it had this noise but now it gets even louder. Today, I have come to a state where my car starts to die if it reaches above 2000RPM in "OD" and can not get any higher then 3000RPM when in "N" or "P". The strange thing is, when I accelerate I can hear the pump working, but reaching towards 3000RPM in "N" The engine started to di e and the gas pump became silent or nearly stopped working, I kept the gas pedal pressed until it nearly stopped, when I released the pedal, the RPM got back to the stable Idle and the gas pump started to make the noise again on the same loudness.

So I assume, that the strange noise is pointing me to the fuel pump, and its malfuntion, I guess my fuel pressure drops at higher RPM and that is why its stopping. I will surely get this replaced to a new ACDelco pump. However I just wanted to know, if there is any other option that can cause my pump to nearly stop when I accelerate.

Should you had any similiar issues and a solution, please let me know. Thank you so much!

 

Replace the fuel filter first, then see how it is. If a new pump is required a Bosch replacement is a better choice then AC Delco. While AC Delco pumps were being made here is the USA they worked.

Not so much now that they aren't.

RBob.

 

Just some more detail to the story, the installed pump was an airtex one, with a new stainer and Acdelco fuel filter.
Tank was totally cleaned before the whole process, because the car sited for so long ago.

I think we got some of the followings:
- Airtex pump failure (my opinion 90%)
- the stainer clogged
- the fuel filter clogged
- some electrical failure?

Just want to mention the pump after the installation was quiet for the first 2 or 3 start, and after started making this annoying noise.
But it worked ok for until yesterday. Pump is 5-6 months old! And car was rebuild and was painted so it was moved minimal, it wasn't in road use just a few miles! So it has minimal work hour in that pump!

 

*** Update ***

We made a test with the fuel pump, the fuel inline has been disconnected and the fuel pump has been manually turned on using the fuel relay.

While getting the fuel out, the pump had no noise, when the fuel line has been connected back, the whining noise came back. Is this because the pressure is too high when connected that the fuel pump must struggle to keep the pressure make the fuel flow?

Any experience with this?

 

*** Update ***

Today we made a test. We shut the engine and manually operated the fuel pump, and the fuel was coming in in the inline and going out on the outline. The Vacuum hose has been removed from the regulator, and as the there was no vacuum, based on my knowledge the regulator should be closed and the fuel should not comeback to the tank. However, it does, which is I guess a malfunction.

I found that when the engine has been shut, there was no fuel coming out from the fuel rail when I removed the inline, where as previously I remember it did.

Tomorrow I'll get this regulator replaced. But in the meantime any comments are welcome.

Cheers

 

This is OK, the FPR regulator should still be regulating the fuel pressure to between 43 and 47 psi. The vacuum hose along with the engine running will lower the fuel pressure.

In this case the fuel pressure will change 1:1 to the manifold vacuum.

RBob.

 

Thanks for the clearing, I had then a completely wrong understanding about its operation.

Now I just don't understand why the pump whines when the engine runs? Cause if the running engine lowers the pressure, then the pump should have an easier job... or thats the cause? Like the running engine puts the pressure and tries to slow down the pump and that is why it stuggles? I am not sure but I feel clue less now.

I am afraid, if I change the pump the fault will remain...

Anyways, thanks for your attention and support!

 

*** Update ***

We have swapped the fuel rail completely, and since that I have no issues no codes no stalling. However the pump still whines, but it needs atleast 15 minutes now as before it took it 1 minute to start and its a bit more quite than before. However I have around 1/8 fuel in the tank whereas before the tank was full.

Do you think that can make and difference in any ways?

Thanks

 

Today the fuel pump will be replaced. I hope that will not start whining... fingers Crossed!!

 

Find the cause! - the filter has fallen off from the end of the Fuel Pump. All the crap that remained at the bottom of the tank got into the pump making it have a lower fuel flow and making it have a whining noise.

Problem solved after replacing the pump!