89formula#1

Hey guys I put my Holley 750 double pumper on tonight and started it up and it was blowing alot of white smoke out the exhaust right away and the idle isn't stable, It usually varies 100 rpm at idle at liek 800 now its at 1200 and its jumpin like that. I thought that white smoke was lean so I changed the jets from the 71 that it cam with to a 74 and nothing happen, so i changed them to a 76 and put a 5.0 power valve in thinking it was blown but still nothing changed, but my plugs were really really fouled out so i changed them and tried it again and nothing and afte rliek 30 secounds of runing the plugs look black. I only messed with the primary jets and the idle mixture screws are 1 1/2 turns out, so what do you think is going on here with all this smoke, its liek i;m lean but foulin out plugs

I forgot to mention that last time I drove the car i put 2 gallons of 112 octane race fuel in it at the track but on the way home I put 10 dollors of 93 in it and that was liek 5 gallons or somthing and i had a little under a 1/4 tank when i put the 112 in so I don;t think thats makign a difference so u??

EvilCartman

iTrader: (1)

White smoke out the tailpipe means water in the combustion chamber. Blue smoke = oil and Black smoke = running rich. Maybe you blew a headgasket at the track. Check your oil and coolant for any signs of trouble. Put the carb back to stock and start over. The jets are not going to mess with your idle, that's what the idle mixture screws are for. As for the race fuel, I've got 110 in mine right now and had 118 in last month, no strange problems.

RB83L69

If it's fouling the plugs black at idle, it's too rich. Try setting the idle mixture with a vacuum gauge.

The smoke could easily be left-over combustion products. In no case does it mean that it's lean. That's a mistake.

Look through this forum under my userID, there's several posts where I describe how to tune a Holley. Sounds like you need some of that.

F-BIRD'88

Put the stock jetting back in.

White smoke does not indicate a lean condition.
water in the engine does create white *steam*.

Why would you start changing jets when you suspect a lean idle.

Main jetting changes tune the cruise and WOT fuel flow.
Not the idle.

Find the water leak.
White smoke also indicates transmission fluid getting into the motor. (vacuum modulator)

SSC

Ive had the white smoke you describe before but if you smell it and look closely its blueish and smells like burnt oil and raw fuel. My problem was caused by too little throttle blade opening causing the engine to suck more air then normal through the PCV system along with some oil preventing full combustion and coming out the pipes more white then blue. Of course you need to add plug fouling ect into that but its probably not water your seeing.

It just sounds like you need to tune this carb properly.

89formula#1

well i just wunted to report back that the white smoke was a lean condition, I put a 6.5 power valve in it and some 74 jets up front with the pump shot giving max travel by messing with cams and bending the arm and I put a .35 squrter in the back with some 82 jets and did the same thing with the accelerator pump and I will have to say that it feels like a totally different car, its so much faster and more responsive, From a roll in first I can floor it and it doesn;t stop spinning till a little into third gear, its insane, the rpms shoot to redline almost instantly. Man i am pumped to keep tuning it and geting more from it, I don;t think 12's are aproblem anymore. Thanks for helpin out guys...