New car...first time at track....need help
 

Hey guys....

KCIR had a test & tune session last night. Took the new Nova up there and made some passes. Did a great burn out....staged up and hit the gas at the green.

Thats when the gremlins appeared.....so thought I would tap the experience and knowledge here for some things to begin checking on to figure this thing out.....

So when the car launched it almost immediately nosed over and sounded like I had a bad miss and would not climb above about 5500 RPM....in first or when I went to second. In park you can rev the engine to 7K with no problem....so the problem seems to be under load.

Thought I might have a fuel pressure problem....we checked the gauge at the carb and it reads about 6.5 pounds...now that is in park with reving the engine up to 6000 rpm....again not under any load.

We checked the timing at 3000 rpm and it was at 28 so I adjusted it up to 34 degrees advanced.

Ran again and really no change.

The car is also having some difficulty starting and idleing....especially in drive.

Car specifics:
78 Nova backhalfed on 9" ladder bar. Running a small block 358 with a PG.....Holley 4150 750 cfm carb..huges 6000 converter. Ignition is an MSD 6AL w/Mallory blaster coil. I was foot braking the car last night and not using the trans brake yet.

I plan to check on some things today....here's my thoughts

* Check carb - verify butterflies wide open at full throttle (peddle)
* Pull & check all plugs
* Check valve springs for any valve lash
* Recheck timing

Any other thoughts/suggestions about things you would check? I figure its a process of elimination.

BTW...even with the problems....loved it!!....and working out the bugs is all part of the game.

Thanks!

???
 

Check and see what Chip is in the 6AL Limiter??
Later
G 8)

Sounds like fuel starvation...

Ya have a healthy flow of fuel when you WOT with engine off?
Accelerator pump intact / sufficient ?
Float level correct ?

Jet extenions :?: :?:





'' JUST MY TWO CENT'S WORTH''

Put bigger squirters and accel pump cams on the carb. Like Mopar said, jet extensions on the rear and make sure your vent tube plastic thingy is on the front metering block. If it's a Holley.

And float level.

Curtis

Re: ???
 

No chip at all.....adding a 3 step this weekend. My assumption was that there would be no limiter with no chip.

Bad assumption?....cause a problem?

HEY MAYDAY,It sounds for sure your motor is starving for fuel.fishmanjoe

Dang guys.....I think I just figured it out. The throttle cable is a little to long and when you put the peddle to the floor the rear butterflies barely open and the squirter is not pumping......the front is wide open but the rear is not. So thinking about that would have me believe that the front half of the engine is getting plenty of fuel and the rear is not ...the engine is trying to come up on the RPMs...but the rear cylinders are crapping out due to fuel starvation.

Am I tracking??

Kind of embarrasing :roll:

In your first post you said you verified that the peddle was bringing it to wide open throttle???

No...that was one in the list of items I was going to be checking.....good thing I did that first :D

from past experiance , if a motor only misses under load it just might be the coil wire or perhaps the plug wires or even the wrong heat range plug,,,for what its worth , at least try these things and I think you will solve your problem...the throttle not opening all the way is not going to make it stumble..

I'd bump your timing up more to 38 degrees and lock it out first.

Fixing the WOT issue will help it get going down the track better but will do nothing for your stumble.
To me it sounds like the accellerator pump circuit(s) need attention.
Make sure you dont have any slack in the arm(s) that operates the pumps, adjust the screw (longer) till you have zero slack and your getting a full shot as soon as you move the throttle blades.
I'd also reccomend a 50cc pump kit in the front of any all out racemotor, especially footbraking it.
There's more to tuning a accel pump circuit than meets the eye, different cams profiles, many different squirters sizes, etc it can get pretty involved in a hurry if this is uncharted territory with you then you might do well to get someone in the know to look at it with you.

Now you say it's hard to get cranked and keep running, especially in drive?
Is it loading up? idling to rich? Black smoke? Your eyes tearing up?
If it is then you'll get a bad bog simply because your plugs are all loaded up with fuel, You need to correct that as well either by setting the float levels correctly or by adjusting the idle mixture screws in or you could have blown power valve. Check for fuel drippiling out of the boosters at an idle.

This is going to be a process of elimination, only do one thing at a time if possible even though it may be a multitude of things causing your problem.
Next time you go to the track be prepared to make adjustments between rounds, leave what helps and put back what doesn't.
Goodluck, Cp

Thanks guys.....great thoughts and suggestions. I'll keep digging.

MY CAR WAS DOING THAT LAST YEAR, I WENT TO A FUEL CELL WITH A SUMP BUILT INTO IT, UNDER LOAD MY FUEL PRESSURE WOULD DROP RIGHT TO NOTHING. THE SUMP KEEPS MY FUEL LINE FULL NOW EVEN WHEN LOW ON GAS.. GET YOUR FUEL PRESSURE GAUGE WHERE YOU CAN SEE IT WHEN YOU RUN IT..

Banging out under load
 

I ran A ChevyII A few years back & had the same problem--This guy came over & handed me a set of plugs,The ones I was Running was too cold-I swear it fixed it the very next run--May not be your problem but its cheap to try-I also ran a msd6al-I also ran a little more timing than your running-38degrees