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@Z06-GXP's suggestion about the timing chain makes a LOT of sense - much more so than a head gasket. You might start by pulling the timing chain cover and seeing how far off it is (assuming that's the issue). It's *possible* that the chain can jump without actually bringing the valves into contact with the pistons if it didn't skip too many teeth.

If your gasket goes and the engine overheats - which will happen very quickly - the resulting warpage in the head could very easily affect multiple cylinders. The pattern you mentioned indicates that there's a serious breach near cylinder #2. If it's bad enough to actually get ZERO compression, it would have to be a very large break.

Normally, for zero compression, I would suspect a valve (or even a loose spark plug). But, you'd have to have at least four bad valves on different cylinders in this case. And, a stuck valve wouldn't give you 85 or 100 psi. I'd bet a beer that it's the head gasket.

While you're in there, may as well do some ARP head studs. :)

Regarding tunes on a high mileage engine: I've been running RPM's stage 2 on my 105k mile LNF for awhile now with no issues. 165psi across the board.

Since it's easy, you may as well go ahead and do the oil test. Add a teaspoon or so of oil to each cylinder via the spark plug hole before running the compression test. Also, on the off chance this isn't obvious, compression numbers will be way off if the test is performed on a cold engine, and the gas pedal has to be on the floor when performing the test in order to keep the throttle open. Don't worry about fuel as the ECM recognizes this as a command to open the throttle while not injecting any fuel.

The oil in the cylinder will also give you more accurate numbers when testing a cold engine.
been thinking about a tune for my 07GXP with 66K. But probably just the GM version so I can pass california smog. thoughts?
 

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been thinking about a tune for my 07GXP with 66K. But probably just the GM version so I can pass california smog. thoughts?

I'm a more forgiving state (TX), but do they really download your ECM firmware and compare it to the stock image to determine if it passes?

All of the street tunes that are available, as far as I know, will pass emissions.

Or, if you're in an OBD-2-only county (as opposed to places that do dyno emissions tests), it's possible to disable the codes that would prevent the car from passing inspection.

For offroad use only. No statements presented herein shall be interpreted as legal advice or guidance. Do not attempt to bypass emissions equipment as this is against the law in many municipalities.
 

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Ray, I honestly don't know. I am not a mechanic, and where I live (north San Diego county) they no longer use dyno just the OBD device plus a visual inspection. I don't know what they can tell from the OBD, but I don't want to take the chance.

Ray, as far as I know, any changes between the air filter and the cat are prohibited in CA unless it has a CARB-compliant sticker. No bigger, free-er flowing intercooler, no bigger, straighter charge pipes, no CAI, no high flow cat, nothing.

I hope I'm wrong.... If someone who lives in California has done some of these things and passed smog PLEASE let me know!
 

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As far as the tune goes: if they're just testing via OBD, then you should be fine. OBD tests look for readiness monitors and trouble codes. If the monitors are ready and there aren't any DTCs (CEL), you should be fine. And, if you have the device (HP Tuners interface), you can always just flash it back to stock before inspection. :D

The CAI and charge pipes provide zero performance gain. (DDM has publicly said as much.) They sound cool and look neat, and make it less of a pain when removing your intake manifold (again) but that's about it. They're bling. (I have them and like them, but they're not a power adder on a forced induction engine.)

If they can spot a high flow cat, they must be paid more than the techs in Texas. But, it's California, so who knows. It's a great mod that lets the engine rev a bit faster.

There are quite a few owners here that have posted about Cali inspection difficulties, including one guy with a Mallet that had all kinds of problems.
 

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As far as the tune goes: if they're just testing via OBD, then you should be fine. OBD tests look for readiness monitors and trouble codes. If the monitors are ready and there aren't any DTCs (CEL), you should be fine. And, if you have the device (HP Tuners interface), you can always just flash it back to stock before inspection. :D
If you do a re-flash make sure you do it far enough in advance that you have driven a full "cycle". A re-flash would look like a DTC reset and they look for that along with the codes themselves.
The CAI and charge pipes provide zero performance gain. (DDM has publicly said as much.) They sound cool and look neat, and make it less of a pain when removing your intake manifold (again) but that's about it. They're bling. (I have them and like them, but they're not a power adder on a forced induction engine.)

If they can spot a high flow cat, they must be paid more than the techs in Texas. But, it's California, so who knows. It's a great mod that lets the engine rev a bit faster.

There are quite a few owners here that have posted about Cali inspection difficulties, including one guy with a Mallet that had all kinds of problems.
What you are saying about aftermarket parts makes perfect sense - anywhere but California. The rule there is that anything emissions related has to be approved, or you can't do it. And, it has to be approved for the model and year of car that you have.
 

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I hear that Oregon is pretty.
 

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Having owned my GXP that spent it's first 11 years in So Cal, I can tell you what I know from experience. I know there are guys that have modified their cars and are getting away with it, but I don't know how. You are right about "no modifications before the second O2 sensor".

Tunes are a gray area. GM came out with the GMPP tune in 2008 and it is not C.A.R.B. certified for a 2007. I don't know how strictly this is followed but it's a risk for your '07. The OBD test shows the vehicle calibration I.D. which would give away a tune, but I don't know if many shops look at that. The GMPP also has different MAP sensors which could be a give away. The Trifecta tune includes a stock tune along with the performance tune. I personally know a guy who would change it back to stock before test day and that worked for him. Just make sure you have run enough miles that your ECM has run all the tests. EVAP takes the longest.

I've failed inspection because the PCV nipple on the plastic intake tube broke and I fixed it with epoxy. That was a modification so I had to buy a new tube.
 

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The CAI and charge pipes provide zero performance gain. (DDM has publicly said as much.) They sound cool and look neat, and make it less of a pain when removing your intake manifold (again) but that's about it. They're bling. (I have them and like them, but they're not a power adder on a forced induction engine
One input on charge tubes. There was a lot of debate about the contribution or lack thereof from charge tubes. One member swore they gave him more HP while others were skeptical. Finally a set of cynosure data was posted that showed interesting results. The stock tubed appear to have a significant impact on high end power. There is a peak in the curve that levels out above 5000 rpm and actually drops hp as you approach redline. When the same car was monitored with after market charge tubes the roll off was gone, at least up to redline. The area under the curve was significant and obvious. So while the after market tubes did not MAKE power, they provided a significant improvement in power production

Mysense is the factory tubes have a negative impact but as a production compromise the negative impact is only seen at full power demand up near redline and for a relatively short time. But of course I HAD to have the better tubes and bought them
 

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Wow...the smognazi state of California. I was at several dealerships with my last job, and all 3 had a guy who had cars that were modded to the max. 2 of them were Supras pushing over 800hp, licensed in California, the other was a 300Z pushing over 1000hp, also licensed in the state of California. How did they get away with it? Were they the personal mechanic of the smognazi? Did they give him a little more green? Next door neighbor? Have pics of him and someone else? How????? I know a 4th guy was trying to expain something about military something. Basically the jist was if you had someone in the military, you could license the car in California and not have to have it inspected till they were out....or something like that. I can't remember the loop hole he was telling me about...
 

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Discussion Starter #32
Thank you everyone for your responses! I'm sorry that I asked a question and then went silent. I lost some Solstice "fire" through this one, haven't had the heart to even read the forums lately. I still haven't pulled the head yet, but will soon.

In the event that the engine needs replacing - what's the best call for a engine that runs a tune? LNF, LDK? What generation? Recommendation on where to buy one?

If I got new ARP head studs for a new engine - can they be switched out, one at a time, without changing the head gasket?

Recommend having the automatic transmission rebuilt while it's out?

37k miles on the car.
 

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The way through this is to start with diagnosing the problems and then make a decision on how to proceed. Its possible that the problem is not catastrophic and you can get the car back to running again fairly quickly. And you have lots of help.

If the existing low mileage block is ok, it may just need head work.

Talk with Dave at Werks who has a lot of experience with performance motors and can give you some good advice.

trust me, I know its frustrating to have a major failure like this happen, and even worse when its the beginning of the season, the new job is freeing you up for cruises . ..

but fear naught! Lets take a look at it and see hat needs to be done.
 

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:) Just remind yourself that it didn't take hyper-trained geniuses to build the engine, and they didn't memorize anything, they referred to manuals.

Hang in there, do this in manageable steps.
 

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Discussion Starter #35
The way through this is to start with diagnosing the problems and then make a decision on how to proceed. Its possible that the problem is not catastrophic and you can get the car back to running again fairly quickly. And you have lots of help.

If the existing low mileage block is ok, it may just need head work.

Talk with Dave at Werks who has a lot of experience with performance motors and can give you some good advice.

trust me, I know its frustrating to have a major failure like this happen, and even worse when its the beginning of the season, the new job is freeing you up for cruises . ..

but fear naught! Lets take a look at it and see hat needs to be done.
Thanks Rob. Ive been pretty discouraged since the whole problem but I'm starting to pull myself out of that funk. I should start pulling the head this weekend.

Ready, Fire, Aim! Thanks for reminding me to slow down!
 

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I tend to look at this as an opportunity. An opportunity to learn. To maybe put in some stronger parts and have more fun.

We have a member who is a retired professional mechanic. He pulled the motor on his 2.4 Sol and installing a turbo kit. He put it back together meticulously and sent us all pictures of the final product. Looked GREAT. He drove it for about a week then due to an installation error it over boosted and destroyed the block, heads etc. He was very upset. As a 35 year pro mechanic you just don't make errors like that . . . .! He put the car up for sale and was THROUGH with it forever!

A couple of weeks later, after no one wanted the basket case, he "found" a new and better motor. He rebuilt it, installed the turbo kit and is now enjoying the car very much.

Stuff happens. The goal is to have "new" stuff happen and not the same old stuff. :party::driving::driving::driving:
 

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Discussion Starter #39
I finally got the head off today!! Cylinder 2 showed 0psi compression before I tore everything apart and it looks like the edge of the piston in cylinder two is damaged. Additionally the cylinder looks stained from something. The edge of the piston is missing so much material so that I can see the rings beneath it. Attached you'll see pics of the broken piston edge, the nasty cylinder wall, a clean cylinder wall for comparison, and the valves.

To recap -
- 07 GXP w/ 37k miles, Car was stock up to 35k miles and since then its gotten - Trifecta tune, PAW tcm tune, DDM Edelbrock fuel filter, DDM CAI, DDM charge tubes
- While driving down the highway I blew smoke, lost power and threw an engine code so immediately pulled over and had the car towed home.
- I didn't have water mixing with oil
- Compression test showed cylinder 2 to have 0psi, whereas all other cylinders seemed to be low 100-120psi with oil added to the cylinder.
- With the head off i can visually see that the edge of the piston is missing, and the valves are all black compared to the other cylinders valves.

What could have caused this?
Have you ever seen this?
- Cylinder 2 was too lean?
- Could this be from faulty injector?
- Could this be from Trifecta tune being ran at Denver elevation? I never data logged the tune after it was installed like I had the opportunity to - mistake?
- Is it coincidence that this problem happened around 150 miles after I walnut blasted my valves?

I'm going to order a LDK block with LNF head from ZZP with a new turbo and ARP head studs. Should I buy a new injector rail from them?

It sure is tempting to drop in an inexpensive carbed small block Chevy! Unfortunately I think the car is too nice to drop in an old style engine instead of a newer LS motor - and thats something I can't afford now.
 

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