The_Ghost

First off, I'm coming here for some extra help. I have an '08 Solstice GXP, which has the same LNF motor that the '09 and '10 Cobalt SS and HHR SS have. I'm coming here because nobody seems to know how to get rid of this code!! So here's my story:




I have been struggling with a p2188 code now for almost ayear. I have exhausted everything I know and need more technical advice. I have no boost leaks. I have other issues. It started with the p0101 and then the p2188 together. The p2188 is too rich at idle. My car is now approaching 80k and not many Solstice and Sky owners have that mileage yet. So my resources are limited on the Solstice/Sky forums. Let me give you what I have done and know about my issue....

I am dyno tuned by ZZP. I have IC piping and a Fujita CAI. I also have Solo Performance Street Race exhaust and a DDM silicone intake elbow, but no other real mods. When this first showed up I tightened all of the my t-bolts on my intake system. I have put several containers of Techron through the car. Which I might add gave my car a terrible issue because it seems to be tuned right at the edge of 93 octane. I also have a backfire issue on decel with the car in gear. It will bang several times on coast down after being on the gas. (I’m thinking this might be carbon buildup on the intake valves) I have replaced the camshaft solenoids to get rid of the p0101, which it did. I have replaced my MAF sensor as the other was really erratic. I have pulled the connectors at the HPFP and cleaned them as I was told that the connectors corrode and cause an issue. I do have an erratic tick from the HPFP (I can post a video of this if needed). It’s not consistent like it was several years ago. I still get this p2188 code…and it’s usually during coast down in gear. If Ipull the car out of gear during coasting, the code never appears. I did smell the oil, and it does smell a bit like raw fuel. I’ve been told it mightbe my HPFP…


Any advice on this nasty p2188 code would be greatly appreciated!!!

exninja

iTrader: (1)

Have you datalogged to watch your fuel trims? Did you take a look at the valves to see how bad the coking is? 80K w/o a valve scrubbing means they are likely going to be really fouled up.

The_Ghost

I have not. I know that my STFT seems to be fine till coast down in gear. Then it sits at -70 and does so till I blip the throttle...then it will hover at idle between -6 and 6. I don't have HPTuners...yet. I use Torque. I know that the valves probably need a good walnut blast, unless you guys here know something we don't on how to clean them!!

Tdubbs

Just for ***** and giggles I looked up your car at work on Identifix with that code just to see if anyone in the professional world had found anything. Seems the most common hit was for the High Pressure Fuel Pump leaking internally into the crankcase, and the pcv was sucking the fuel vapors causing it to run rich.

Now, I'm not going to say this is a fix, so don't just go buy a pump and throw it in. But you can check and see if the oil on the dipstick is higher than it should be, or if it has a raw gas smell. Just other things to look into since you have been chasing this down for some time.

As to cleaning the valves, the walnut blast does work best, but there are many(myself included) that have done it by hand with chemicals and scrapers/brushes. If you do go the hand route, the more time you spend the cleaner it'll be. So if you did all 4 cylinders in 2 hours, you almost guaranteed didn't do a good enough job.

The_Ghost

I appreciate it Tdubbs. I was thinking HPFP as well. But didn't want to throw $350 at the car for the pump. But, I think I might be stuck at this point. Here is a vid of the erratic tick from HPFP.

Tdubbs

Sounds a bit odd, but videos of noises are always harder to discern than being there. Tell you what though, let it run for a bit to get hot, then drive it for a few minutes where your Torque app says fuel trims are rich, then park it and pull the dipstick and see if it has a raw fuel smell to it. That way if it is fuel inside the crankcase, you have the best chance of smelling it. If it smells raw, it's probably the pump.

Sharkey

iTrader: (1)

did this start happening after you got the tune done?

exninja

iTrader: (1)

If it ends up being the HPFP, and you don't want to spend $350 on it, you can try to find someone swapping an LDK and see if they'll sell you their old HPFP. Just a tip.

The_Ghost

The first code I got was for a bad MAF sensor, which I replaced, then I got the p0101 and p2188 code together about 5k after my dyno tune. I did replace both solenoids and got he p0101 code to go away. I've been struggling with it for over 10k miles now and a just over a year. Funny part was I was going through the GM service manual at work this morning and nowhere in the diag/repair for a p2188 does it say anything about the HPFP. One of the last operations is to throw 4 new fuel injectors at it. No wonder GM dealers can't fix the LNFs properly!

Tdubbs

Like I said I wasn't saying it was a guaranteed fix for it, but it was interesting info. I included the supposed diag from Identifix for that code, and it shows what the most common repairs have been. I didn't include everyones descriptions, but all the HPFP replacements are stated from fuel contamination in the engine oil. Would still need to verify that is the issue though.

ForceFedDork

to summarize you had p0101 (maf rationality) and have P2188 (too rich at idle)... and nobody questions the intake? or the tune?

was the car tuned WITH the intake? if a canned tune, was ZZP aware you had this intake? does zzp have a canned tune that comprehends that intake?

most likely you have an air measurement issue, i'm guessing due to the intake (maybe misaligned with the tune).

on this forum i've also seen some cases where the wide band o2 sensors drift, could be O2 sensor???

"gurgling / popping" on decel, with an open exhaust when NOT in DFCO i would say that is normal, irrelevant to this issue, but you mentioned it and seemed to be concerned about it.

your profile states Waterford, is that Waterford, MI? if so, i could log your car with HP tuners if you want.

umrdyldo

iTrader: (1)

I agree, check for boost leaks first to clear up the P0101 and I'll guess that clears up the other.

Tdubbs

The only reason I wasn't questioning the intake/boost leak was because he said the car no longer had a P0101, it only has the P2188. Now I can't say I trust someone over the internet, but he did say he went through all of his t-bolts, and I'm just assuming the vehicle was tuned with the parts he listed on the car by his wording.

Still, even in his original post he said the oil smelled like raw fuel, and while running pig rich could cause that, so could the HPFP. I only looked at Identifix for him just to give him more things to check into so he didn't buy more parts without diagnosing what the issue was.

Sharkey

iTrader: (1)

so i guess my post doesnt count?