I have a 2007 HHR LT1 with a ecotec 2.2 non-turbo engine. It is hard to start but seems to run ok after it does start. I did a fuel pressure test and when I turn the ignition to on I get 30psi for 2 seconds the 0. While starting and eventually running I get 30 psi but immediately drops to 0 when I shut the engine off. I change the fuel pump and checked again with the same results. I put the old fuel pump in a bucket of water and wired it directly to the battery and got 60 psi which is what it should be. I did a voltage drop check on the new pump with .15 on the positive and .5 on the negative side. Although the negative side seems high it is within the .5 range.
I guess my next step it to look at the injectors.

Does anyone have a suggestion or had a similar problem?

Has anyone ever wired the fuel pump directly to the battery with a relay? i think I will hook up the new pump to the battery and see what pressure I get that way.

Thanks

 

If the engine is not running the pump only runs for 30 seconds. Should check it with engine running.

To narrow between pump and injector:
Test #1 ignition ON engine OFF, force fuel pump on pressure should be 50-60 PSI
turn pump off
If the pressure decreases by less than 5 PSI in 1 minute the pump is bad.
If it decreases by more than 5 PSI in 1 minute there is a leaking injector.

Test #2
Relieve the pressure to 10 PSI, if the pressure decreases by more than 2 PSI in 5 minutes the fuel pump is bad.


You should get the same results engine on, this assumes you have a Tech2 tool. There is already a relay

 

Welcome to the site, look for wet fuel lines to , believe me it’s much easier to change the fuel lines while you have the tank down to change out the fuel pump.

I had had the same issues a few years ago, I changed the fuel pump first then 4 months later in the dead of winter the vapour line started to let fumes out, then the pressure line developed a pin hole.
I waited 2 weeks for the fuel lines. and had to drop the tank again because the oring at the tank on the pressure line got nicked and leaked .

I wish I knew then , what I know now.

 

I have checked the fuel pressure with the engine running and it never gets above 30psi and drops as soon as I turn off the ignition.
I do not have a tech 2 tool so I wired the pump up to the battery direct and still only get 30 psi.
I guess I will replace the injectors and see what happens.
No wet lines and no sign of leaking anywhere.

 

Why the injectors? Is it running rich? Is there poor MPG. Is there black smoke out the exhaust? Gas in the oil pan?

Are you hooking the gauge up to the Schraeder valve on the fuel rail?

If enough fuel was pumping through the injectors to account for 25 PSI there would be other symptoms.

I would look for a leak in the vapor line and replace the fuel pump.

 

If the Vapor line was leaking wouldn't I get a EVAP fault code.

The only code I get id a P0171 which I have not been able to find a vacuum leak.

The fuel pump is new and I blew out the fuel lines to make sure there was no blockage.

I'm thinking injectors because the pressure drops to 0 within a couple of seconds.

I think I will drop the tank and check the lines before I change the injectors.

Thanks for all the help.

 

P0171 is a EVAP code Could be the EVAP purge valve is sticking open or a cracked vapor line.. You said no codes.

 

New pump, 30 psi, old pump in bucket of water , 60 psi.

Perhaps a bum new pump?

P0171

https://www.obd-codes.com/p0171

check low fuel pressure, it should be 50 to 60 lbs.

the vapour line in mine was corroded under the insulation hard to see.

 

I think it is a bum new pump, I reinstalled the old pump after I cleaned it and I now have 60 psi and the engine runs great.
It still drops to 0 when I turn off the ignition but at least it is running good again and it cleared the P0171 code it had.

 

I suggest you return that new defective pump, get you money back , then order a new pump.
What brand is that pump? I’ve had good service from AC Delco pumps, don’t for get RockAuto gives us a discount code, good for 5 percent off.