Hello everyone.

I am working on my 2007 2.4 ECOTEC HHR LT with 110K Miles.

On a recent long highway trip from Las Vegas to LA and back, my car started by throwing P0171 "Lean Code" and started running less than optimally. We made it home, but I knew we had an issue. The next day, it would only start after the ignition/starter is turned 3-4 times. BTW, it has not had the starter switch recall taken care of because it has not been an issue and the local dealer said we had to "pay for it and then get a refund for the recalled service item?" The recalled ignition is a separate issue, I believe.

I suspected a fuel pump/delivery issue. I put a fuel pressure regulator on and when the ignition was initially energized there is always zero PSI. Not sure if this is normal for an HHR 2.4 ECOTEC? Most cars/trucks I have worked on have fuel rail pressure at all times when ignition is energized unless there is a leak. At least they pump pressure when the ignition is energized and this is not the case on my car at this time. Also, when I cranked the car the first 3-4 times, there is not pressure then, usually on the 4th try, it will pop up to 35 PSI and the car will start and run normally.

I suspected a fuel pump as this is a common malady for HHRs with my kind of mileage and there is no external fuel filter. I ordered one on Ebay and installed with no problems. As soon as I fired it up with the new pump, it fired right up and seemed to be fixed. It ran fine for 1 full day and then it went back to not starting after sitting unless the ignition and starter are energized 3-4 times. After that, it will fire right up unless it sits for a few minutes. I will mention, it is very hot here in Las Vegas and also, I did bleed the fuel rail.

Here is what it is reading (fuel pressure) when I start it after sitting. I connect the fuel pressure gauge. There is zero pressure. I will energize the ignition (without turning starter) and there is zero pressure and no fuel pump sound. After turning starter 3-4 times, the fuel pump will suddenly produce 35PSI and the motor will start and idle and seem to run fine. If I turn off the ignition, the pressure goes back to zero immediately every time (not sure this is normal, suspect not). If I restart it at this point, here is what happens. I energize the ignition without turning starter and gauge shows zero fuel PSI. As soon as I engage the starter, the fuel pressure pops up to 35PSI and the motor starts. It will do this again and again without fail unless the car sits for 5 or more minutes at which point I will need to energize the started 3-4 times to get fuel pressure again.

I'm starting to suspect a fuel pressure sensor, if one exists external of the pump. What electrical signal tells the fuel pump to run? Is it the ignition being energized or does the motor need to be turned over?

I've been working on cars for ages and am a little perplexed by the fuel pressure data I am seeing.

Thanks for your time and help

Benny

 

Your other post in a separate thread has been moved here and deleted. Please don't post the same item in multiple places - it makes it impossible to follow the progress or determine which one to reply to.

 

You can try reading a few of the other related posts here - just use the SEARCH tool near the top of the page and look for p0171.

ie: https://www.chevyhhr.net/forums/prob...ressure-50695/

There can be several causes of the p0171 code, including the fuel pump as you noted, and as noted in the above link. Keep in mind though that the new fuel pump might have failed already - was it a brand name unit?

 

Benny , welcome to the site! Please check out this link.. P0171 relates to yes possible duty fuel filter, also a dirty MAF sensor( clean it with the proper MAF sensor save cleaner spray!
also the 1 O2 sensor reading lean, this is most likely due to a cracked or broken flex pipe , check just between the exhaust manifold and the first O2 sensor

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

If it the flex pipe there are repair kits on eBay like this example

Semi Direct Fit Exhaust Flange Repair Flex Pipe Replacement Kit w Gasket FX2061 | eBay


And here is the how to


https://www.chevyhhr.net/forums/how-...ex-pipe-31536/

 

You stated "energize the ignition without turning starter". I'm assuming you mean turning the key to the ON position without engaging the starter. If so, then you should be able to hear the fuel pump run(if it is). Get someone to listen or turn the key on while you listen at the filler door.
Make sure it is turned to On and not just Accessory. The pump should only run for a few seconds if working correctly.

If you don't hear the pump running, then it could be a number of possibilities.

 

IIRC; the fuel pressure should be something like 65 PSI.

P0171 means either a vacuum leak or a bad fuel pump.

The fuel pressure regulator is part of the fuel pump assembly in the gas tank, what did you replace? Did you try save money and only get the pump instead of the assembly?

The switch is part of the ignition recall, there has been a miscommunication.
Here is a link:https://my.chevrolet.com/recalls

The pump will only run for 2 seconds if you don't start the engine.

 

OK, just to clear a few things up...

Apologize for the double post, Whopper...won't happen again.

It has not thrown the P0171 code again since I disconnected the battery and put in the new fuel pump...which probably reset the computer. I am not concentrating on vacuum leak issues that cause that code because the vehicle is not even able to maintain proper fuel pressure to start the motor, as I have described. Unless there is some sort of sensor which would tell the fuel pump not to energize? I am investigating if there are other possible causes of (what I perceive as) the weird fuel pressure readings...before I assume a faulty pump. Though possible, it seemed like an unlikely cause, but not the first time this has happened. I was also thinking about rechecking the plug connections near the fuel pump installation location just in case it is loose and causing an intermittent fuel pump electrical power issue?

When I say "energize the ignition without turning starter", I do mean "ignition ON", not accessory. I was expecting to hear the pump kick on and the associated pressure build up on the gauge, then cut off, but that is not happening until I turn the starter on...weird, huh?

Again, thanks for all the responses...you guys are helping me think this through. I am leaning toward returning the pump and getting another new one.
I bought a complete fuel pump assembly online. It was a new "discount one" from Ebay and the idea that it is already faulty has crossed my mind. When first installed it did sound like it was firing up when ignition was switched to on and pumping pressure then cutting off as I would normally expect in other fuel injected cars, but I did not put the fuel pressure gauge on it at that time because it instantly appeared to fix the problem.

 

No problem with the double post - it happens. :)

I'd suspect the new pump - do you have a link to the ebay item? Donbrew might be able to spot something with it that does not sound right.

Hey donbrew - is there an easy way that you know of to test a fuel pump before installing it?

 

Don't know about testing.

Some brands are known to be junk.

Any thought given to relays?

And, evidently we are still ignoring the switch recall, which is another possibility. If you are still thinking "intermittent". LINK:https://www.chevyhhr.net/forums/gm-r...updated-49640/

35 PSI instead of 65 PSI is not an intermittent problem.

 

I d return the questionable pump assembly and order the AC Delco unit
AC Delco Fuel Pump
I found this at the Parts Geek site



Sale Price:
$213.33
with FREE Shipping



Part Number: 19079-05411404

Notes: GM Original Equipment