JNorris

iTrader: (4)

I am hoping you all can give me a few suggestions that might help me determine why I have black smoke at WOT.

My mods are listed below:

TEA stage 1.5 5.3L heads milled .015
TR224/114 cam
Stock length push rods
Stock (factory) timing chain
LS6 intake
30# SVO injectors
Mac headers
Ported TB
De-screened stock MAF
Fast Toys Ram Air kit
ASP pulley
Built 4L60E with a PT4000 stall converter

I use EFILive, Innovate Motorsports WB O2 meter, and LS1Edit to tune the car.

LTFT are between -.8 and -10 while at cruse and 0 at WOT.
WOT AFR bounces around between 12.7 and 13.1 depending on what gear and RPM.

My AFR looks good. I have confirmed proper operation of the WB on other cars.

I know black smoke is not always an indication of a rich condition. It can also be an indication of incomplete combustion.

Is it possible that maybe my pushrods are too long and are not allowing the valves to close completely?


Any suggestions?


Thanks

John

Hardtop

iTrader: (3)

Did you put thread sealant on the rocker arm bolts? Mine smoked until I sealed mine.

Bruce

02WSsicks

iTrader: (6)

Make sure your COT is turned off

Ragtop 99

iTrader: (7)

Does it happen in a sustained period at WOT or just at the beginning? Bad O2 sensors can cause the car to belch black smoke when you first hammer it.

shep28

iTrader: (4)

why would that stop the smoking?

Grimes

iTrader: (3)

black smoke usually means you are running rich for some reason, blue is for oil burning (hence the rocker arm bolt idea- sometimes in ported heads they break through to the threads of the bolt)

COT is a good idea; i would check the O2 sensors too

JL ws-6

iTrader: (50)

Where is the timing at, if the pushrods are too long, that's probably gonna mess with it

shep28

iTrader: (4)

[QUOTE=Grimes] sometimes in ported heads they break through to the threads of the bolt)

explain this

JNorris

iTrader: (4)

Thanks for the replies.

The rocker arm bolt threads are sealed and COT is turned off.

It blows black smoke as long as it is at WOT. What is strange is that if I am at 70%-80% WOT (but still in PE) there is no smoke. When I go 100% TP is when it smokes (black). The car seems to smoke more towards the end of the run or just more in 3rd gear. This kind of points to a bad MAF not reading the airflow correctly at the higher levels. However I would think that the wide band O2 would show this.
I have the WB in the right hand side of the exhaust. Maybe I have a bad injector on the left hand side and this is causing the black smoke. I will swap the WB to the left side and see what the AFR is,

My timing is set at the stock 28 degrees. When I go WOT there is no (<1) KR in 1st or 2nd gear but as soon as it hits 3rd gear I get 1.5 to 2.5 degrees of KR.