As most of the elders here know I've been fighting with a P2188 - Too Rich At Idle since I was dyno tuned last year. I have been watching for some commonalities now that it's less frequent. Many have thought that maybe it was due to my Fujita CAI....a common issue creator by this company for our cars. The P2188 has gotten less frequent since the replacement of my intake and exhaust solenoids. So here's what I've witnessed happening just before the code is set.....
1) A/C is on and motor is around the 205 degree mark. If left in gear I will get some backfiring and then the CEL while costing down in gear and coming to a stop.
2) Several miles (about 10-20 miles) the vehicle won't go to full boost. It seems sluggish and slow. I get 13-14psi of boost at WOT, when I'm normally getting 23-24psi and able to light my tires up in 2nd and 3rd. I DO NOT have a limp mode that I'm aware of. Once the code is reset, I get my 23-24psi of boost again.
3) I will usually have a real crisp snap to the exhaust when pushing in the clutch to shift, usually about 5-10 miles and does this continuously, as it does with #2.
So, what I'm getting at is I'm wondering if it isn't deeper then my CAI. I have yet to find a factory one to swap mine out with. Any suggestions guys???
Soooooo.....time to revisit this. The CEL for this code is coming on more frequently now. My average run home from work is causing it to come on about 3 times. It's about a 24 mile commute now. It's getting worse. I have been "logging" as best I can with Torque and have found some rather interesting things. My AFR when idling is now down to an average of about 12.3 - something that seems a bit low to me. So that tells me right there, yes, I'm "too rich at idle" per the p2188 code!! According to what I've read on diagnosing this code, the STFT are within parameters, but on the lower end of that "normal" range. According to the freeze frame when the CEL is set, they have averaged -19.2, they are supposed to be > -20. Which could be the reason of the backfiring on decal after the CEL is set. My next step is to try and find an OE airbox or purchase a different CAI, whichever I can do in the next 2 months. Another thing I noticed this morning while letting it idle after a hard drive on the freeway was a sound that it was making. It sounded almost like timing chain slap.....but the fan turned on before I could really get in there to listen. My 2 biggest concerns on this code are the fuel pump possibly going (or the regulator pushing too much fuel) and carbon buildup on the valves. Both are a bit more money then what I want to spend!! I really need to find someone that hptuners in the Detroit area so I can datalog and try to sort this out.... Thinking I may replace the O2 sensor this weekend....
While I don't have any advice on your situation, I would like to share my experience with code p2188... it's been a real pain for me. Unfortunately, it only happens for me in the summer during hot days. When I first got my GXP a few years ago and it started happening, I thought it was related to having a full gas tank but then it would happen with half a tank, finally I figured out it happens on hot days. My car would start just fine in the mornings and afternoons after work, but if I drove it to running temperature and then parked it for an hour or two, when I go to start it again it would start but die instantly and then act like it's vapor locked. The only way I've found to start it during this period is to have the gas pedal down half way while starting it, and then most times I'll smell gas once it starts. I've posted about it here on the forums and found no solution as of yet, I've replaced the purge valve three times over the years and no permanent fix. The dealership keeps telling me it's this or that, most recently they told me the MAF sensor, so I replaced that yesterday and will give it some time to see if the issue still occurs. Thankfully I haven't seen the CEL since last year, but the issue is still happening on hot days where it won't start after sitting for an hour or two (usually coolant is around 140 when it fails to start). I haven't replaced my O2 sensor yet, the next steps if it continues to happen for me is to have the dealership run another diagnostic and possibly have them replace the pressure regulator. I asked about replacing the fuel injectors and man do I hope it doesn't come down to that... they quoted me at nearly $2400 to have all 4 replaced.
I hope you get yours fixed, this code seems like real trouble for anyone with these cars that get it!
I don't know if you're tuned...or if you have a CAI. I have both. I have a CAI - Fujita, and a dyno tune. When my dyno tune was done, it was about 40 degrees outside. And this CEL sees to come on more when the weather is warm. All indicators seem to point toward the CAI or the tune I have....but can't prove either yet. Mine did start and die yesterday....the first time it's ever done that!! But started right up after that.
Maybe someone can help me understand this a bit more. I datalogged a longer (35 minutes) road trip with many different speeds. What I have noticed is that the AFR fluctuates all over the place at idle. One idle it's at 14.7, after another stop light its 11.1 or less. My STFT also dramatically fluctuates with that. Sometimes it's < -10 and > 5 while other times it's stuck at -30.47. So I'm thinking maybe 1 of the following:
- Split IC
- Bad HPFP regulator since it does tick eratically
- Bad O2 sensor since I seen fluctuations of .67mV to over 2mV from one of them.
- Major carbon buildup on the intake valves
Any ideas guys? It is getting worse. I turn on the A/C and the CEL comes on within 30 seconds. If I run without it, it can take up to 30 minutes before I get a CEL depending on how I drive...I'm actually thinking with the way the readings are moving so much that it's a sensor that's going bad....
Thanks Latin....I managed to get the ear of a GM Engineer that specialized in the LNF and owns 4 LNF powered cars including a Sky. He told me first to try and fix my erratic HPFP tick. And that is done by cleaning the plug leads on it. He listened to my video, looked at what little info I have from Torque and said, "I can tell you for 90% certainty that your HPFP leads have corrosion....and that probably will even fix your p2188 code. What happens is that when the ECM doesn't have a good connection to the HPFP, it automatically opens the regulator and goes full rich. Thus the reason you have an erratic, inconsistent tick and very inconsistent STFT at idle." Which is what is happening as he showed me. He doubted that I needed to replace it as it sounded okay. He also proceeded to say that many people have replaced their HPFP unnecessarily due to this issue. I will do this tomorrow as soon as I get home from Boston. If nothing else, I have his phone number and he told me to bring it by later this month and he would help me with it.
I believe I have fixed it!!! I pulled the connector to the HPFP and cleaned it. I drove our cruise last night, no code!! Not even pending. All of the STFT look good and the AFR has gone back to normal. One more test today and that's to drive it with the A/C on. Even the HPFP has gone back to ticking normally.
I can say with 99% certainty, it is fixed!!! I ran with the a/c on yesterday for 40 minutes, no code, no pending code!!! 23psi of boost the whole time. I'm so thankful my path crossed with this new co-worker. One side note that I did mention before that was told to me. If ANYONE is having issues with HPFP codes, please, clean your connections before replacing your HPFP. He told me that many people have replaced their HPFP unnecessarily due to just dirty connectors. Thanks everyone for your help on this, I really appreciate everyone helping out with suggestions. This not only fixes the odd tick, p2188, but will most likely also fix erratic STFT readings and erratic rail pressures. My whole issue started out with a back-fire. Then the CEL started coming on. It got more and more frequent as time went on until I couldn't even drive it 22 miles to work without getting a CEL 2 to 3 times. I hope my experience can help someone else out there that is chasing a CEL consistently!! Clean the plug and connector first!!!
Well...over 600 miles, no light....until yesterday with the A/C on. The car has been running great. No issues and my love affair and my permagrin are back!! Was sitting in traffic yesterday in 85 degrees and had been there for a while and decided to turn on the A/C. Car steadily climbed to 208 degrees within a few minutes and when I took off I noticed a lot less power. Checked and sure enough, p2188 pending.... With that now said, I would have to now agree that I'm pretty sure it's my tune now. So I've contacted Trifecta to see if I could have the selectable tune installed with my dyno tune....we'll see....
I found a solution to my problem, hopefully this helps someone out there with similar issues. As it turns out, there isn't necessarily a problem with my car, but more with the fuel I use on a daily basis. I had someone suggest to me to try Ethanol free gas, because Ethanol has a lower boiling point, it could be causing a form of vapor locking in the gas lines during those hot months and messing everything up, throwing codes when things get out of hand. Sure enough, I switched from my regular gas station, using the Super 91 octane fuel to an Ethanol free option and the starting problem went away. My only real concern is that this gas station shows minimum octane rating of 86, which is too low, but it doesn't show what the actual octane rating is. In either case, after two months of running Ethanol free gas and no issues, I switched back to my regular gas station and the problem came back that very day! I switched back more out of desperation because I let it run way too low and didn't have time or enough fuel to travel to the Ethanol free pump across town. In either case, if I can find a high enough octane rating Ethanol free fuel, I'm definitely switching to that! Especially during the summer.
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