Car stop's running during hard Launches

[onebadgrandprix]

There seems to be alot of experienced people on this board, so I will give this a try!

The problem I have is that when the car get's up in the air is shuts off, when I spin the tires a little and get a bad 60' it does not miss a beat. The MPH is the same hooking or not! I've got a BBC with NOS fogger, 1050 dominator, Magna Fuel 500 pump and regulator, Digital 7 box. I've relocated the ground's for the fuel pump and ignition system. Put a hose connecting the vents on the carb with no luck. I'm lost, does anyone have a suggestion on things to look at or what could be wrong!

Thanks,
Paul

[Monty Mikho]

Do you have jet extensions in the rear of the carb?
Also check the micro switch for the nitrous system on the carb..
Also check to make sure the fuel floats are adjusted correctly.. Should show around 1/4 of the window when motor is at idle..

[onebadgrandprix]

Do you have jet extensions in the rear of the carb?
Also check the micro switch for the nitrous system on the carb..
Also check to make sure the fuel floats are adjusted correctly.. Should show around 1/4 of the window when motor is at idle..

Thank you for your response.
I have jet extensions in the rear, float bowls are good.
I have not changed the microswitch off the carb yet, cause it did
not make any sense to me that the motor would shut off just cause
the nitrous was deactivated. Again thank you. If you have any other
suggestions I would greatly appreciated it!

Paul

[Jim Monson]

Check for loose ground wires.

[Chris Uratchko]

You say floats are good... do you have a tube running from air vent tube to tube? I've had my car up pretty high before without the hose from tube to tube, but I have the baffles for the vents...

[Monty Mikho]

Man you really mean turning off eh? What style of battery are you using? Are you using an alternator?

[Six_Shooter]

Man you really mean turning off eh? What style of battery are you using? Are you using an alternator?

On this line of thinking...
Which way is the battery installed. I.E. is the long direction of the battery going from front to back of the vehicle, or accross the vehicle?

[onebadgrandprix]

I'm running an alternator with an optima battery in the trunk terminals facing the back of the car! Do you think the battery is shorting out itself when the car raises up?

Chris: I do have a vented hose linking the two float bowl vents.

You guy's rock!! that is the most input I've gotten so far!
there is a video of the car on putfile, I will see if I can post a link so you could see what the car is doing!

Thanks
Paul

[onebadgrandprix]

Here is a vid of the car cutting out. hopefully this link works!

http://media.putfile.com/onebad-and-nova

[onebadgrandprix]

On this line of thinking...
Which way is the battery installed. I.E. is the long direction of the battery going from front to back of the vehicle, or accross the vehicle?

Do you think it makes a difference on which direction the batter is mounted?

[katman]

If the battery is marginal and you launch real hard and the battery is long side front to back, the plates in the battery can short out against each other. You might try a different battery. If it fixes it and your battery is front to back, change to left to right so it doesn't happen again.
On another thought you don't have a long rod w/handle on your battery cut-off switch that could move enough on launch to kill the battery but not actually throw the switch?
This isn't a newer car with a roll over switch that kills the fuel pump is it?
When it dies, does it sputter and die or just cut out instantly? How far out of the gate does it happen?

[Beyond]

One of the drag radial cars around here had a problem with that a while back, when it hooked hard his main power wire would hit the header or something and eventually started to short out only at launch. They chased a lot of things till they finally found it.

[onebadgrandprix]

If the battery is marginal and you launch real hard and the battery is long side front to back, the plates in the battery can short out against each other. You might try a different battery. If it fixes it and your battery is front to back, change to left to right so it doesn't happen again.
On another thought you don't have a long rod w/handle on your battery cut-off switch that could move enough on launch to kill the battery but not actually throw the switch?
This isn't a newer car with a roll over switch that kills the fuel pump is it?
When it dies, does it sputter and die or just cut out instantly? How far out of the gate does it happen?

If you see the video you can hear the car shut off, but sometimes it sputters. (i've got the gold GP in the near lane). Great Idea on the battery, With the responsed I've gotten, I think I'm gonna have the car rewired over the winter. In my mind I can't see a "silver bullet" to kill the problem.

Thanks for the Feedback!
Paul

[Tom McDunnah]

Have you fixed the car?

I got an idea that the Tachometer is shorting out,and if it is still doing it in the spring, try unhooking the Tach,,see a few guys have intermitting problems like what you are experiancing. That might be your culprit

Let Me know.

Hope it helps........Tom

[onebadgrandprix]

Have you fixed the car?

I got an idea that the Tachometer is shorting out,and if it is still doing it in the spring, try unhooking the Tach,,see a few guys have intermitting problems like what you are experiancing. That might be your culprit

Let Me know.

Hope it helps........Tom

Last time out it still did it!
Holy Crap! that is one hell of an Idea! I will give it a shot!
Thanks,
Paul

[K*A*B]

i had one of my cars shutting off during hard launches and it turned out to be a wire in the steering column was loose , when the car spun , it wouldn't throw me back into the seat and the column wouldn't flex causing the wire to lose contact
i was getting out of the car one day and pulled on the steering wheel to climb out and the car stalled
i'm not saying this is your problem but it is stupid things like this that are really hard to troubleshot or easily over looked

[onebadgrandprix]

You guy's are giving me a great list of things to run down!
Thanks

[Duner]

Mine was acting the same way - and would only quit if it made a good 60'. It turned out to be the simple spade connector on the ground wire of the coil. On launch it would move the wire just enough to make a bad connection. If you popped it into nuetral it would start back up again.... only to screw up again 5 passes later! (usually just in time for 1st round) I got rid of the spade connection and it's been fine every since.

I know how frustrating a deal like this can be.... Hope you find it soon!

[Jay Allen]

The only time I have seen a car do this is when something is amuck in the fuel system.

I'd check EVERYTHING associated with fuel. Even the spring and diaphram in the regulator. Unhook the the fuel supply at the carb. Check it flowing.

Even re-think the fuel supply at the pump. On a hard launch is the fuel doing stupid $h!t in the cell or tank? Do you have the foam in the cell? Home made sump?

[onebadgrandprix]

I'm in the process of rewiring the car right now!

I've replaced the entire fuel system with the same results!

Thanks for the input!
Paul