markm75

I have a v4 AWD LT 2010 equinox with about 135k miles on it (engine was a lemon and also changed around 50k).

I frequently have been getting that error code.. and more recently misfire on #1 code.. and now hit with more constant service stabilitrack errors which i think does something to the throttle power when its showing..

I can usually restart the car to clear the service stabili track.

I had what was believed to be throttle body issues in the past.. had it cleaned but didnt help.. car will often still run for about 5 seconds after turning off the key (not always), sputtering.. it used to sputter on startup too, but hasnt lately.
I also tried getting better gas but that didnt help.

I'm concerned on the stabili track.. worried about getting stranded as well.

From what i've seen online some suggested throttle body replacement, but its my understanding since direct injection this shouldnt matter and in most cases didnt help.. the end result for many was a whole new computer (which one, cost must be high i assume if this is it).

I'm taking it to the dealer for diagnosis next week, which they also charge $50 just to check codes and hook up to a computer.

Any suggestions?

Thanks in advance

ruley73

If you are not also seeing an ABS light, I'd ignore the Service Stabilitrak warning since it primarily relies on ABS components to function. Diagnose and fix that misfire first and foremost. That is likely causing a domino affect. A misfire introduces more unburned fuel into the exhaust stream which will cause a rich running condition to be detected. The computer can and will disable Stabilitrak if it believes the engine is running in a manner that would compromise the computer's ability to implement Stabilitrak during an emergency steering maneuver (i.e. suddenly turning the steering wheel to avoid an accident). The computer is programmed to believe that no Stabilitrak at all is safer than trying to apply a handicapped Stabilitrak during an emergency steering maneuver.

Check the basic things first like spark plugs, air filter, and ignition coils. Some other possibilities could be a bad upstream oxygen sensor, an exhaust leak, bad MAF sensor, clogged/dirty fuel injectors, or a clogged catalytic converter. If you are not seeing any throttlebody-related trouble codes, then it is probably fine. A throttlebody's fundamental function (controlling intake air volume) never changes, regardless of whether or not an engine uses direct injection so you can ignore that advice as well.

markm75

Thanks for the reply..

I took it to my dealer today.. not sure my dealer knows what they are doing or has a clue how to fix things on this issue.

They couldnt find the same codes.. though the misfire code did show up, this time two different cylinders.

They started off recommending a "tuneup", changing spark plugs (just did and prior to this had the issue too), induction service (had the throttle body cleaned recently too, didnt help)...

Then said they'd get into "swapping coils" (not replacing either, swapping) to rule out coils.. (so they at least touched on this one)

They also hammered on, if you dont put the same brand/model spark plugs can have issues, well i'm pretty sure the place that did them did and the issue was there prior.
I'm leaning towards either they or another place testing new coils to rule that out i guess.

I asked about the throttle position sensor, they said no codes showed up for that.

markm75

update: the dealer decided to check the plugs and try some coil swaps..

They said i'm using something other than AC Delco and thats why i may be having issues (from other shops around with good knowledge i dont think this is the case, plus i had these issues prior to having the plugs changed).
They said they found fuel in the oil.

They tried swapping coils, no luck (not adding new ones in the mix but trying the others).. now i have 2,3,4 misfiring apparently.

Back to the drawing board

markm75

From another source, it sounds like my systems match that of a "high pressure" fuel pump failure.. i'm guessing the one in the fuel tank (which i had thought about replacing before, but skipped as i think its sealed in the fuel tank). (IE: might be expensive)

ruley73

There is actually a second fuel pump near the engine that ramps up the fuel pressure so fuel can be injected directly into the combustion chamber. This pump is known to fail on early direct-injected 2.4 liter engines. In fact, GM recently issued a voluntary recall for this exact issue.

http://gm.oemdtc.com/6491/43180-prod...ox-gmc-terrain

markm75

Thanks for that link. I had high hopes but when I called the dealer they said based on my vin it didn't apply, which seems unreal given the symptoms. I guess now my only choice might be to call gm and see if they can help and or have a shop check with a gauge to prove it's the culprit, though seems a no brainer. Skeptical that GM will but I will try.

markm75

I tried contacting GM first.. gave them the link and # for the recal.. they said the same thing.. well first they said the link is 3rd party and doesnt always apply.. then said it doesnt apply specifically to my vin.. which is ridiculous. They said all their recalls are vin specific too.

I still might try another deal just to see, either way i'm probably out $500-$650 if not covered and confirmed to be the issue (gauge check still needed, but seems like a dead ringer to me).

markm75

Update: Went to my regular trusty local shop, they put the gauge on the HPFP.. nothing out of the ordinary showed up, which is odd considering all these symptoms seem to suggest it was at fault.

They put injector cleaner in the tank to try, nothing changed so far. They are suggesting it might be the catalytic converter or related..

Interestingly, now my error codes are showing P0420 Catalyst System Efficiency Below Threshold, along with the usual P0172 System too rich.

HeelandToe

I've had the fuel in the oil problem on my 2010 LT FWD twice and replaced the HPFP mounted on the engine. It fixed the issue the first time (I had scavenged one from a wreckers) and the second time I replaced it with a new one. That seemed to fix it for good in that regard as I've put 15000 miles on it since. The recall notice came out a few months after and boy was I peeved...