SSMOKE

I bought my 2007 Z06 in 2009 with 2,900 miles. At 10,000 miles and because I was paranoid, I upgraded to WCCH Stage 2 heads and added a TORQUER 110 cam. (560 RWHP and a competent tuner.) Prior to that, and at around 7,000 miles I added a CAI, headers and a tune.

I am a weekend warrior and have never driven on a track. Generally my cars sits Mo through Fr. She now has 17,000 miles and after sitting for five days she does what you see and hear in the video. In addition, if she has been sitting, I get CHECK COOLANT LEVEL on the DIC. The coolant level is always good, like the rest of the fluids and the 50/50 DEXCOOL/water is fresh enough.

If I started her everyday I wouldn't notice a problem, meaning she fires right up and does not smoke. Further, I have never gotten the CHECK COOLANT LEVEL unless she has been sitting. However, as you can see in the video, something is not right. I did a search on the CCL warning and from what I can tell, it is an algorithm that initiates the warning. Just in case, I just disconnected the battery for a re-set because it is definitely a VERY ROUGH idle after she finally fires after five days off. I am sure some may ask is it white/coolant or blue/oil smoke. Honestly, I do not know.

LMK what you think. Unfortunately, the competent tuner/mechanic that I mention above is no longer on the island and it is a real challenge to find competent help. Chevy dealer is not really an option.

http://vid284.photobucket.com/albums...pst1g5gbp9.mp4

marco383

It sounds like a leaking valve seal problem. If enough oil gets past the seals during the dormant period, it will take a few seconds to burn it out, which could account for the rough running.

Michael_D

Start with the basics.... Make sure the plug wires are seated on both ends. Check your air intake, make sure it hasn't come undone.

So was / is the coolant level low?

SSMOKE

Thanks marco383 and Michael_D. The battery disconnect reset did not solve the problem because I still get CHECK COOLANT LEVEL. The coolant level is not/has not been low. All the plug wires and CAI are GOOD to GO! I took all the plugs out today and while they were looking more oily than I thought they would, they (All eight.) were mostly consistent.





The single plug picture is from cylinder #6. This plug has some oil pooled at the very top of the threads. Is this abnormal?

Michael_D

The start in the video, was that after sitting a day? And no, there should not be any oil on the plugs.

It's pretty quick, but it appears to fire/miss, then it catches. First a puff of blue, then black. The blue could be from oil, but the black is from too much fuel because it was cranking too long.

Not sure why you would get the coolant CEL. I need to study up on that.

pkincy

Given no problem with a one day start and only the problem on a 4-5 day start, I would concentrate on what would be leaking down that slowly. A hard start problem after heads/cam would normally be a tune problem but the good one day start rules that out. Marco 383s suggestion of bad valve seals sounds possible and at least very easy to fix by putting in new seals with an air compressor holding the valves up and a valve compressor and 16 new seals and a 6 pack.

BWFitz

Since there is no problem after sitting for just a day, I am convinced that the next thing to do is a leak-down test. That will tell you if your valve guides are worn enough to allow oil to seep past them into the cylinders. That is a common problem with after-market heads after you put a few miles on them.

spra4u

Michael_D

Leak down will not tell you if the guide clearance is excessive, or if you have bad seals. The springs will hold the valve on the seat. It is an excellent test to quantify leak rate past rings or valve seats and if you have a crack in the cyl liner, head or head gasket. Or the piston as well.

Turbo-Geist

My guess would be valve seals or worn valve guides. You could have the valve guide clearance checked. If the stem to guide clearance is within spec then more than likely it only needs valve guide seals. The seals are cheap to replace and can be done with the heads on the car. Valve guides will obviously require the heads to be removed for service.

Another note, supposedly there was a run of factory titanium valves that had a very rough chromium nitride coating. Even a routine tumble polish wouldn't smooth the surface properly and therefore the new guides would experience premature wear.

If you are going to do some inspection, I would start with the #6 cylinder first since your plugs seem to indicate it has the greatest issue.

SSMOKE

Thanks guys. This is disappointing to say the least. marco383 the Check Coolant Level CEL may just be a coincidence, but I always get ALL three (CEL, hard start and smoke) or NONE of the three.

I guess that I will start with the valve seals. Not something that I feel comfortable doing, but will figure something out.

SSMOKE

I just talked to WCCH and they are pretty confident that the valve seals they use (Viton) are not the problem. They mentioned that the guides could be worn again.

This is crazy. Only 7,000 miles on my new heads and the problem/paranoia continues.

RamAir972003

Check the heads for just safety precautions in sure wcch will help you if guides are worn....

rio95

Wow these are some odd symptoms. Your plugs definitely suggest its rich in my opinion based off the dry flat black color. Wonder if you have a vacuum leak. A scanner would help things.

What more did they say about the guides possibly being out of spec already? Have they seen that happen in 7,000 miles? I've got 14k on my wcch heads and my plugs don't look like this.

Michael_D

No reason to jump to the conclusion valve guides are shot. Lot's of wild assed guessing going on at this point. You need to follow a process when trying to diagnose a problem.

How long has this car started up like what your video shows? Always, or is this something new? And again, is the video after the car sat for five days?

Do you have a code reader? I'd like to see the actual code(s). The 'check coolant level' may be a red hearing, but it may also be causing the ECM to do weird things. It does happen.

How many miles/years of use do the plugs have? And what's the entire plug number? (they look like crap btw and should be changed)

08mojo

Really good questions that have not been answered.

Tech

Long start could be cause of pressure bleeding off in the fuel lines. You can test this by turning the car to the on position (press the start button with foot off of clutch), then off, then on, then off, then start the car. If the car fires immediately, it was likely air in the fuel lines.

Over time, you can get gunk in your radiator that attaches to things, including the coolant temp sensor. Perhaps the car runs and circulates the coolant enough for clean off the temp sensor until you shut it down and gunk accumulates back on it. I don't believe the coolant temp sensor is related to rough/long start.

Tech

Btw, the plugs do look too dark. What injectors are in the car?

SSMOKE

I was talking to Deb who works in the front and when she went to get the guy in the back (Dave) I think, he was busy, so she was relaying information between the two of us. (Meaning Dave and I.) What I got, was that Dave was telling Deb to tell me it is either the guides or the rings. Obviously, not ideal circumstances for over the phone diagnostics.

I thought that I replaced/changed the plugs when I did the heads and cam. However, since they are AC Delco, I think that they are the original plugs. Meaning nine years old with 17,000 miles. 10,000 miles and then heads and cam for the last 7,000 miles. The full number is 12571165. Thanks, I will definitely change them.

Stock injectors. Car is a 2007 with 17,000 miles. Also, I switched to REDLINE 5W30 when I had the heads/cam done. One more thing. I have KOOKS 1 7/8" headers with NO cats.

Michael_D

I have similar logistical / competency challenges as you do living in Alaska. That's why I do my own work, and why I learned how to tune. Too bad you are not on the Big Island. I go there often, and would be happy to lay hands on the car for you on my next trip. I will work for booze

With your latest round of answers, I would start with the plugs. Change them. Go cooler than stock. NGK TR7's (non-iridium) are probably the least problematic plug, and they are cheap.

That "check coolant level" message has me stumped. It may just be a bad sensor.

Hard starting after it sits for a week, and not just overnight makes me suspect an injector. You may have one or more leaking, then the fuel puddles on the piston or in the intake, not fully evaporating. They when you go to start it, it's basically flooded and you get the smoke when it catches. - That's just a theory. One way to check the injectors, is a pressure test. Cobble up what you need to connect the fuel rail to compressed air (with a gauge) and see if you have bleed down.