Theservicegroup777

Good day folks ! I've got a head scratcher on my hands so I'm reaching out to the wonderful folks on here to see if anyone may know something I've missed. I've searched my code on here and those results I've already went through.

2010 HHR 2.2L Auto 140K Flex Fuel ( not running and never will run FF)

Im getting p0171 lean code however its definitely running right by the coal I'm rolling . Haha I havnt had the car to long but ill give back story and what i know. I bought it it was barely running, ran way rich as in woukd even idle and cat had failed ,so off to the shop for major tune up. After tune up it is drivable if you don't get embarrassed easily . Cause it will die out at the worse times. Drive thru and middle of intersections haha

Replaced:
Catalytic converter
Both 02 sensors
Coils and Plugs
Evap Purge Solenoid
Map and Maf sensors
Injectors and Insulators
Throttle body
Air filter

P0171 yet its running extremly rich , can smell out the exhaust and horrible fuel mileage, stumbling , rough idle and acceleration. On hard accel you can see black smoke.

Diagnostics-

Fuel PSI 55

Confirmed Map and Maf are working via scan tool.
MAF was reading 6.2 g/s . I think this is way high but I could be wrong. I typically base 1 gram per 1 liter of displacement.


Fuel Alcolhol Content was at 73% - I reset that and it's at .5 %

Instantly upon start up Short Term and Long Term Fuel max out. 32% and 26%. Forgive me on the actual numbers I'm not near the data right now.

Engine at idle will be stumbling and instantly as I reset Fuel trims , I can hear her idle up smooth out and sounds perfect. Fuel trims creep back to max in about 10 seconds.

I suspected a major vac leak causing engine to add fuel to compensate.

Sprayed everywhere with carb cleaner no change in engine rpm.
Plugged off brake booster and evap no change .
Evap command is 22% at idle. Commanded to 0% no change. Commanded 100% engine dies . This is to be expected and confirms evap is functioning.
Checked and sprayed intake boot for a cracked near the hose connections . Its good .

Maybe Bad MAF off shelf reading high ?
Cracked intake or bad gasket ? I dont hear any whistle and carb cleaner sprayed all over intake and gasket area doesnt change engine behavior.
Dead Head or Cylinder ?

Thanks in advance for the help folks

Oldblue

Check the fuel pressure, it’s possible the fuel pump is failing

greg8453

Not sure how a failing pump would cause high pressure. Maybe the regulator but I would be looking at the load PID's. Does it set the code at idle or is it running rich under load?
How does it do with MAF unhooked? What is TPS at idle?

Theservicegroup777

Hey guys ,
oleblue fuel psi is at 55psi. Static and at idle

Greg, after clearing the code it will immediately come back as pending on the first start up. I drive it ( best I can lol) maybe 2O miles MIL comes on. Load at idle with A/C on is 28%

donbrew

Why did you replace all of those parts that have their own codes? Just more money than you need?
Did you use the correct ACDelco 41-103 plugs?
Have you done a compression and leak down test?
The MAF should 2-6 g/s at idle
Have you checked the MAP? The BARO should agree with actual.
Check the flex pipe and the flange connection. Which way was the cat replaced?
Look at all of the vac tubes, including the brake booster and the air horn. The air horn can get cracks around the PVC connection or the clamp is on backwards so it does not seal.
I have found spraying stuff around is pretty useless, especially if it is already rich.
STFT should be +10 to -10.
LTFT should +10 to -10, near 0 is optimum.
Did you de-coke the injector ports?
Is the ECM original to the engine? Correct firmware? Maybe someone replaced it with a pre-2009 unit.
Has the Alcohol content finished relearning?
Correct O2 sensors for FF? The alcohol content is measured by the O2 sensors.
Have you been clearing the codes frequently? That is bad, codes clear themselves after repair and the OBD2 testing has to start over the EVAP test can take 2 weeks.
What is the I/M readiness status?

greg8453

Load PID's are TPS, MAF RPM. These are what the PCM uses to determine fuel delivery.
6 plus gps at idle is more than double what it should be. Are trims going/staying high while cruising? Try unplugging the MAF. The PCM will calculate load and substitute a value.
At idle smack the MAF. if engine stumbles it's bad.

Theservicegroup777

Don,
Yeah parts are cheap for this car and its good insurance as I travel the nation for work. So I'd rather spend a few hundred in my driveway than get stranded out in the heat spending a whole lot more.

Yes, correct plugs were used .
Map and Baro checked out respectively
I have not done a comp leak down, this was one of my thoughts in my original post and I'll put that on the to-do list .
Flex pipe and flange are ok no leaks
Ive checked all Vac Tubes
Air Horn ? What are you calling the air horn?
ECM I havnt checked, I'll check
Bosch O2 Sensors i can post up part # but im sure they were for this specific engine.
P420 code is why cat was replaced.

I have cleared the codes a few times . Im not clearing them every 5 minutes in hopes my problems go away. Typically after service or a repair was made . Either way it's going to take months to relearn if all I can get it to do I lope in my driveway puffing out Blake smoke . Somethings not right still.

Greg,
I'll have to load those 3 pids first chance I get and report back results .

I'll check trims at cruise and post back.

Unplugging the MAF does nothing to the engine. It's stays running with its sketchy idle . Scan tool no longer reads it and I get the MAF code. I can try another MAF and alway return it .

donbrew

Bosch sensors suck (opinion). NGK/NTK are much better, they make ACDelco.
Air horn is the rubber tube between the air filter and the throttle body.
Until the Alcohol content is re learned nothing will be right assuming the ECM is not from a non-FF.
One member had a broken brake booster connection on the manifold. Another had a cracked check valve on the booster.
Don't need to clear codes ever. It might make thing run better for a time but fixes nothing. After a repair a permanent/historic code will remain for about 100 key cycles. Many codes need multiple istances to set the CEL.

Oldblue

55 psi, what’s the leak down time ?
fuel injectors are they good and clean? Any air leaking past the orings? Cracked insulator?

Theservicegroup777

The air horn/ intake boot is fine I've checked. I've already isolated the brake booster as stated in my original post . I understand how codes work . Codes cleared or not , can't relearn a thing for a car that isn't drivable. I'll look into the o2 sensors although personally there's nothing wrong with Bosch IMO. I'll also check the ECM as you suggested. I never though about that , but you could be on to something. Thank you so much for your help. I'll let ya know what I find out .