Bought buddy's z28, needs work. Help.
 

Bought a '98 z28 M6 with pretty much all suspension work done except a watts link. Few things I need help:

1. Blinkers do not work but hazards do.

2. CEL blinks when car is warmed up. I did check the pigtails and coils to see everything is in place. Will diag codes today

3. Car smokes white, grayish, when fully warmed up. Buddy claims its because its cat-less and Needs an oil catch can because of the PCV.

4. Radio hasn't worked since my alternator went out. ( replaced that and also serpentine belt same day)

And will be replacing o2 sensors today to see if it leans out the Air/fuel ratio.

Any suggestions?

1. That'll happen when any of the bulbs are dead. Check bulbs and connectors.
2. No codes, no help.
3. White smoke is burning water (headgasket or cracked something). Blue tint in the smoke is burning oil (something is damaged).
4. Radio and alternator aren't connected, check the wiring and fuse panels.


Suggestions.... pull the codes, check ALL fluids, compression test, check the normal maintenance items.

Hope your buddy didn't screw you, good luck.

well here's the thing,

I started it today and let it idle til it up to operating temperature, revved a few times and only black smoke came out from being catless. CEL wasn't flashing. everything was working fine. but other days where I take it out for a drive, CEL will start flashing and car will feel slightly sluggish and then white and gray smoke will start appearing. oil pressure stays the same, nor does it overheat.


https://cimg0.ibsrv.net/gimg/ls1tech...e3238879c2.jpg

this is my engine. my buddy did the LS6 valley cover and intake swap. but the other picture displays the PCV visibly going into the intake manifold. could this be a reason my car smokes when its being driven and at stops.


https://cimg1.ibsrv.net/gimg/ls1tech...9c0aaf781b.jpg

picture as reference.

The connections look right but you are missing the PCV check valve. The valve is a one-way check valve to prevent clean intake air from going into the crankcase.

What you describe could be a lot of things, pull the codes to help narrow it down.

Pulled a code for cylinder 5 misfire. Replaced the spark plug. Runs great now. And less smoke but still noticeable. Will Install a check valve soon

Lack of spark could cause the extra rich condition (black smoke) but it won't cause white (burning coolant) or blue (burning oil). You still have more to diagnose and fix.

Check valve should cut down on the blue smoke.

Are you losing coolant? You said its not overheating but that doesn't mean you aren't leaking/burning coolant.


How many miles on the motor/car?

Haven't lost coolant. White smoke isn't present anymore. Now it's just more dark gray and blue tint. I'll do a compression test in the near future.

The motor is from an 02 z28 and has 130,xxx miles now.

Ok, lets back up a sec, its very rare for an ls to blow a head gasket. With 130k on the clock has it been given a tune up recently? Not to waste moneybut if the plugs wires and fuel filter are old then they could all stand to be replaced along with cleaning the maf and replacing the air filter if needed. That would eliminate a lot of possible causes of anything really.

Also you probably dont need a pcv valve. You have an ls6 valley cover (PO must have installed) in 2001 they uused an external pcv like the pic you posted, but in 2002-2003 they changed the cover to include the pcv underneath and then jst used a small hosefrom the cover to the intake, just like what you have pictured. So unless your buddy got a hold of a 2001 cover you dont need an external pcv because you have one under the cover. Now that doesnt mean you dont need a catch can, any pcv system on an ls leaves a lot to be desired so you could still be sucking up soil oil into the intake.

I have modified more ls motors than I can count and I have never seen cat delete cause it to run rich enough where black smoke is coming from the exhaust unless under wot. So like I said a tune up would be a good start. By that same sentiment I have seen cat deletes cause gray smoke usually at cold startup but at times even under normal operating temp. A dirty maf sensor can easily cause the extensive rich condition you're describing.

Next if you still suspect a coolant leak into the motor then smell the exhaust, does it smell like coolant? How about the oil is it milky? Does the coolant have oil in it? If all these things check out ok and you're not losing coolant like you said its 99% not a HG leak. If you really want to be sure do a leak down test (sucks on an fbody) or go get a testing kit that uses the blue dye liquid in a bottle from the auto parts store to detect combustion gasses in the cooling system.

Plugs and wires were changed 5k miles ago. Code is cleared and only pops up the two 02 sensors. And it was a pcv valve that was built in. I do not smell coolant or lost coolant. Oil looks normal. Just burns a quart every other drive which is about 30 min each. Will be conducting a leak down sometime next week. I forget that it also has an EGR delete. Haven't checked out fuel filter yet. Cleaned MAF sensor 2 weeks ago thoroughly. Cleaned air filter as well.

LS6 valley cover does not use a external PCV.

In regard to your turn signals not working but hazzards working, I'd bet money it is your T56 Reverse Back-Up Light Lamp Switch. Check to see if Fuse is blown 2nd fuse from front of car on top row. The switch costs 15 bucks from auto part store and is located on the passenger side of the transmisson, 22mm wrench fits it perfect that should fix your turn signal problem unless there is a short somewhere else.:)

Just so you know bad O2 sensors will make the car run rich causing the smoke, essentillay the PCM thinks the motor is lean and dumps fuel in it, How does it idle on cold start, O2's are not used during cold start and WOT, if upon warm up the idle is rough but smooth prior its probably bad O2 sensor. After you replace them maybe pull a few of the spark plugs to check for possible fouling.

Thought the LS6 valley just has a baffle under the port and no check valve at all. Learned something today lol

yup it was exactly that! Used an AC delco branded switch.

mine has no cats, the LS6 PCV conversion and it doesnt smoke at all..


I did have a catch can but that didnt really do much so I just run the LS6 setup

I'm the one that sold him the car. Are you sure you should be giving out your advice? You don't even know what a LS6 PCV system is...

Am I reading that right that you are burning a quart every hour of driving? That is some serious oil consumption.