Fuel pressure problem
 

Has anyone had a problem with low fuel pressure when the fuel pumps have both been replaced along with the regulator? The dealer says the computer is fine and communicating all information correctly. The HHR SS cranks and "wants" to start but wont.

Whopper loves you.

"
Ouz

Dear Whopper, I am not an internet person so I'm not sure how this site works. Sorry that I have a life outside of the computer. I thought this forum was for people like myself to GET help with problems such as my low fuel pressure problem. Thanks for nothing. I'm glad the Silverado SS people and the Vette people are a much more polite and helpful bunch."

Dear Ouz

Well I am sorry we have not lived up to your expectations. But Like I have said on your original post (while trying to remove your other two duplicate threads on the same item - all posted within minutes of each other), we can't help you. Using the site here is not rocket science yet it seems way beyond your capabilities. So therefore I recommended you call GM and escalate the problem with them. Yes, we can continue here and go round and round with you opening new thread after new thread, with you repeating yourself over and over without adding new info, but that would be counterproductive. All that would do is make it more frustrating for people trying to help you - and not get you anywhere. So please give GM a call and escalate it with them.

What is the fuel pressure from the tank to the high pressure fuel pump(HPFP) ?
Measured at the HPFP inlet.

What is the pressure output from the HPFP ? I know it won't crank, but the HPFP is a mechanical pump so it will achieve some pressure when turning over.

As a wild guess. Have you checked for contaminated fuel ?

Sorry. I haven't been here in a bit. Just had to make a note to this^.

:winner:

That is all...

The pressure into the HPFP is 35-40. The HPFP only bumps it up to 65-70. All three HPFPs are the same. The car does crank. It shouldn't be contaminated fuel as it didn't quit or anything. It wasn't a new tank of fuel. It was driving and running great. No power loss or sign of any problem. Normal day. I stopped for lunch and when I came out it wouldn't start.

The ECM signal to the pump is only 7 volts which I think might be a problem but the dealer says that's normal. I've also been told that it may be 12 and drop immediately to 7 without a load.

The dealer also thought the ohms were too low across the pump but again all three pumps were exactly the same.

10. Ignition ON, command the fuel pump ON with a scan tool. The fuel pressure should be
between 345-414 kPa (50-60 psi).

Step no.10 from the repair manual. Sounds like you may have a low pressure issue going to the HPFP.

Fwiw. Mine shows 72 psi on the RPD with the key on, engine not running. This is fuel tank pump pressure.

I misspoke before....the pressure into the high pressure fuel pump is 68. Out of the high pressure fuel pump is 70. The pump is not bumping the pressure. All three pumps are the same pressure output. To my thinking it has to be a computer issue but the dealer says its not. What else could it be?

As said, the high pressure pump is mechanically driven, so if it isn't working then something broke.