A question for you head and cam guys.

[johnsZ06]

Is anyone who is running a decent size cam and "supposedly" has a good tune, noticing your exhaust tips still sooty?

My tips will turn black after a few WOT runs even though I have 13:1 commanded and showing. The rear fascia of my car is constantly spoted with soot!

Maybe I need to hire a chimney sweep to correct this problem! :nixweiss:

[TAQuickness]

chimney sweep will help.

I had a soot problem for a while. would even leave exhuast tracks on my driveway during warm up. My problem wasn't in the tune. It was oil getting thru the pcv. During my last tear down, I upgraded to the ls6 valley cover and still run a catch can. I only get soot now when it's time to empty the catch can.

[johnsZ06]

chimney sweep will help.

I had a soot problem for a while. would even leave exhuast tracks on my driveway during warm up. My problem wasn't in the tune. It was oil getting thru the pcv. During my last tear down, I upgraded to the ls6 valley cover and still run a catch can. I only get soot now when it's time to empty the catch can.

Really? That's interesting. I already have an LS6 valley cover. When I removed my intake not to long ago to install new lifters, I noticed quite a bit of oil in the intake. I wouldn't have thought that would cause such a sooty exhaust. I guess I'll have to give the catch can a try!

[TAQuickness]

Oil does wonders in the combustion process

Does your oil smell like fuel? If so, you are running rich, part of the soot problem. Fuel in the oil will change the viscosity making it easier to get thru the PCV system.

You might also try an idea posted by Joecar (I think this post is in the lounge section). His thought, and a damn good one, is to re-rout the PCV to pick up from the oil filler neck. IIRC, the Dodge Caliber has a similar style PCV system.

[Dirk Diggler]

Could it be not enough timing in the PT areas causing an incomplete burn in the exhaust system

[johnsZ06]

I've never noticed fuel in the oil.

Do you think of just venting both vave covers and eliminating the PCV sytem would be worthwhile?

[johnsZ06]

Could it be not enough timing in the PT areas causing an incomplete burn in the exhaust system

I suppose anything is possible. I asked this very question yesterday on LS1tech about how much timing is enough and only got one response. A search wasn't helpful either.

I am running 28* at peak RPM's and 1* less around 4400 RPM which is where my torque curve peaks.

[Bruce Melton]

I had that problem when I had a bad MAF-- new MAF fixed it. I am olde school.

The oil in intake is a tough one and I have tried everything (ls6 valley, no PCV valve, breather vent, catch can etc) and still get it. For me the soot and "black ass" as I called it, was not related to oil in the intake as much as super rich startup.

[TAQuickness]

I'm not a big fan of breathers, as it eliminates the vacuum on the top end and tends to get oil everywhere under the hood. Although it has worked for some guys.

[johnsZ06]

I had that problem when I had a bad MAF-- new MAF fixed it. I am olde school.

The oil in intake is a tough one and I have tried everything (ls6 valley, no PCV valve, breather vent, catch can etc) and still get it. For me the soot and "black ass" as I called it, was not related to oil in the intake as much as super rich startup.

Bruce,

Have you since eliminated the problem?

Guys in the Corvette club nick named my car "dirty butt". :anitoof:

[Bruce Melton]

I'm not a big fan of breathers, as it eliminates the vacuum on the top end and tends to get oil everywhere under the hood. Although it has worked for some guys.

I hear you but I am currently using a newer GM part that has a check valve in it and looks stock. Works well and sits low.

http://home.new.rr.com/meltn/vcap.JPG

[Bruce Melton]

Bruce,

Have you since eliminated the problem?

Guys in the Corvette club nick named my car "dirty butt". :anitoof:

"black ass" -yes. Still gets C5 dirty quick but not sooty. Still get oil suck, esp during track days. I think when you are off the trottle at high RPMs the vac in the intake is too much.

[TAQuickness]

have a part number and ball park cost on that check valve?

[johnsZ06]

have a part number and ball park cost on that check valve?

Same here! Enquiring minds want to know!

[dfe1]

Have you tried getting more aggressive with DFCO? The overlap associated with a "performance" cam means a fair amount of fuel will be sucked right through the combustion chambers at low rpm. Part of the problem could be coming from raw or partially combusted fuel entering the exhaust port during deceleration.

[Bruce Melton]

Oil Leak Under Extreme Cold Temperatures (-34 Degrees Celsius, 30 Degrees Fahrenheit or Colder) (Install Vented Oil Fill Cap) #05-06-01-014 - (May 9, 2005)
Oil Leak Under Extreme Cold Temperatures (-34°C (-30°F) or Colder) (Install Vented Oil Fill Cap)
2004-2005 Buick Rainier
2003-2005 Cadillac Escalade Models
2004-2005 Cadillac CTS-V
2003-2005 Chevrolet Avalanche, Express, Kodiak, Silverado, SSR, Suburban, Tahoe, TrailBlazer, TrailBlazer EXT
2003-2005 GMC Denali Models, Envoy Models, Savana Van Models, Sierra Models, Topkick, Yukon Models
2004-2005 Pontiac GTO
2005 Pontiac Grand Prix
2003-2005 HUMMER H2
2003 Isuzu NPR/NQR Commercial Models
2003 Work Horse Custom Chassis
with 4.8L, 5.3L, 5,7L or 6.0L Gas Engine ( VINs V, M, T, P, B, Z, G, S, U, N -- RPOs LR4, LH6, LM7, LM4, L33, L59, LS1, LS6, LS2, LQ4, LQ9)
Condition (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1656273&psdid=297&evc=sm/lss1-1656273)
Some customers may comment on an engine oil leak under extreme cold temperatures (-34°C (-30°F) or colder). The customer may also comment that there may be some oil seepage out of the engine oil level indicator (dipstick) and/or out of the front or rear crankshaft seals during engine operation only.
Cause (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1656273&psdid=297&evc=sm/lss2-1656273)
Under extreme cold temperatures (-34°C (-30°F) or colder) and extended driving conditions, the PCV system may experience a freezing condition and shut off all crankcase gases to pass through the PCV system. This may cause crankcase pressure to rise steadily and, in some cases, this high pressure unseats (pushes out) the oil level indicator from the indicator tube and causes an oil leak during engine operation.
Important: If a visual inspection indicates that oil is still leaking from the front or rear crankshaft seals after this bulletin has been performed, then further diagnosis must be performed using the Oil Leak Diagnosis and/or Crankcase Ventilation System Inspection/Diagnosis in SI. Refer to the following SI document number(s) in this bulletin and print a copy for further assistance in diagnosing this condition.
•
Oil Leak Diagnosis (Truck) (SI Document ID #204344)
•
Oil Leak Diagnosis (Car) (SI Document ID #1406822)
•
Crankcase Ventilation System Inspection/Diagnosis (Truck) (SI Document ID #1246823)
•
Crankcase Ventilation System Inspection/Diagnosis (Car) (SI Document ID #954724)
Correction (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1656273&psdid=297&evc=sm/lss3-1656273)
Follow the service procedure below for diagnosis and correction of this condition.
Inspect for the oil fill dipstick being pushed out of the dipstick tube and that there is engine oil seeping out when the engine is under operation. This condition could be caused by the PCV valve freezing shut.
If an icing or freezing condition is found with a PCV valve inspection, then replace the oil fill cap with a vented oil fill cap.
Use a new vented oil fill cap, P/N 12589430. A vented oil fill cap will regulate the crankcase pressure between 15 kPa and 18 kPa. This will prevent the over pressurization of the crankcase under the freezing conditions of the PCV system. Once the PCV system thaws out, the crankcase gases will pass through the PCV system and normal crankcase pressure will be restored.
Inspect the engine oil level . Start and operate the engine under normal conditions and visually inspect that the engine oil leak has been repaired. If another engine oil leak has been detected, then refer to the above mentioned SI Document Numbers for further assistance in repairing the condition.
Parts Information (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1656273&psdid=297&evc=sm/lss4-1656273)

Part Number

Description
12589430
Cap, Oil Fill (Vented)

I am sure that that is more than you wanted to know but:
You need to cut the spring so it will respond under crankcase pressure which is easy to do. The cap is < $10 thru GM. I found it new on Ebay for $7.50.

http://home.new.rr.com/meltn/engcap.JPG

[johnsZ06]

Have you tried getting more aggressive with DFCO? The overlap associated with a "performance" cam means a fair amount of fuel will be sucked right through the combustion chambers at low rpm. Part of the problem could be coming from raw or partially combusted fuel entering the exhaust port during deceleration.
No I haven't. Actually, I've never bothered with that table. I've been concentrating mostly on VE and timing.

I'll have to take a look. Can you offer any suggestions?

EDIT..I was just looking at the table and it appears it wasn't meant for an M6.

[johnsZ06]

12589430
Cap, Oil Fill (Vented)

I am sure that that is more than you wanted to know but:
You need to cut the spring so it will respond under crankcase pressure which is easy to do. The cap is < $10 thru GM. I found it new on Ebay for $7.50.



Thanks Bruce!

[TAQuickness]

thanks Bruce ;) Looks a might bit nicer than the one I have now

[dfe1]

EDIT...You may have hit on something. I looked at the TPS for fuel shut off and it's set to 1.5 or less at any rpm. I know that when my throttle is fully closed it reads something like 4.5 with the EFILive scan tool! I've tried resetting my TPS but it always reads 4.5. I thought it was normal but perhaps I have a TPS adjustment problem or worse yet, my TPS has gone south?
My guess is that there's nothing wrong with your TPS. Don't forget, your car has ETC which means the IAC function is handled by throttle opening. My C5 normally runs 3.9 to 4.3% tps at idle. Yours should be a bit higher because of the cam. I'll e-mail you some DFCO tables to experiment with.

[bink]

Mine has the dirty butt thing going on, speedway white...............guess I need to hook up that LPE catch can I bought - last fall!!

:cheers:
joel

[johnsZ06]

Mine has the dirty butt thing going on, speedway white...............guess I need to hook up that LPE catch can I bought - last fall!!

:cheers:
joel

Ha...I thought I was a procastinator! :bash:

[Bruce Melton]

Mine has the dirty butt thing going on, speedway white...............guess I need to hook up that LPE catch can I bought - last fall!!

:cheers:
joel

It was not the catch can that cured "black ass" it was getting the pig rich MAF prob fixed. Dirty butt is part of the C5 design, me thinks.

[bink]

It was not the catch can that cured "black ass" it was getting the pig rich MAF prob fixed. Dirty butt is part of the C5 design, me thinks.

My MAF is an IAT sensor holder at this point in time.;)

:cheers:
joel

[johnsZ06]

My MAF is an IAT sensor holder at this point in time.;)

:cheers:
joel

I keep switching back and forth and to tell the truth, I don't notice much difference.