Drag Strip Issues (W.O.T. Cutout)

[70grande]

So I took my car to the dragstrip for the first time today, and while I ran pathetic times, I had a blast. The only problem is that when I tryed to slam the pedal down, my car would sputter and start to stall out, so I never got better than an 11.5 on the 1/8 mile.

I cant figure out what could possibly be wrong. I would come up to the staging area, do a beastly burnout (with no problems of cutting out) and then line up. The, as soon as the tree turned green I would punch it out and the tires would spin a little, hook up, and then at about 40mph it just started to stall and sputter and backfire and pop and everything that would bring disrespect to a car at a dragstrip. It did this all three passes (with a bigger audience for each pass unfortunately). And, even when I let off the gas, it would stay in the disabled state, it felt/sounded like it wasn't even running on all cylindars. The only way I could get it out of this state was if I put the car in neutral (I have an A/T) and briefly put the car through full throttle, which it was perfectly capable of doing with no bogging down or poping or sputtering. After I did this, it would run like nothing had ever happened.


On my way home from the strip however, I was getting on the freeway and going from a rolling start of about 40, I punched it out and it slammed into overdrive and got all the way to 90 with no problems what-so-ever.

I cant figure out what on earth would cause this. Is it the fuel/air mix? Is it my timing, even though I have a Pertronix electronic ignition? What the hell is going on?

Thanks for the help!

 

[blown65]

So I took my car to the dragstrip for the first time today, and while I ran pathetic times, I had a blast. The only problem is that when I tryed to slam the pedal down, my car would sputter and start to stall out, so I never got better than an 11.5 on the 1/8 mile.

I cant figure out what could possibly be wrong. I would come up to the staging area, do a beastly burnout (with no problems of cutting out) and then line up. The, as soon as the tree turned green I would punch it out and the tires would spin a little, hook up, and then at about 40mph it just started to stall and sputter and backfire and pop and everything that would bring disrespect to a car at a dragstrip. It did this all three passes (with a bigger audience for each pass unfortunately). And, even when I let off the gas, it would stay in the disabled state, it felt/sounded like it wasn't even running on all cylindars. The only way I could get it out of this state was if I put the car in neutral (I have an A/T) and briefly put the car through full throttle, which it was perfectly capable of doing with no bogging down or poping or sputtering. After I did this, it would run like nothing had ever happened.


On my way home from the strip however, I was getting on the freeway and going from a rolling start of about 40, I punched it out and it slammed into overdrive and got all the way to 90 with no problems what-so-ever.

I cant figure out what on earth would cause this. Is it the fuel/air mix? Is it my timing, even though I have a Pertronix electronic ignition? What the hell is going on?

Thanks for the help!

Would it clear up after that one problem area? Or did it do it down track also? My guess is a fuel issue, I would think if it was ignition it would show up under load in the same area in each gear. How much fuel was in your fuel tank. Anyone see the runs and can say they were seeing smoke when it did it, or clean out the exhaust?

 

[70grande]

Would it clear up after that one problem area? Or did it do it down track also? My guess is a fuel issue, I would think if it was ignition it would show up under load in the same area in each gear. How much fuel was in your fuel tank. Anyone see the runs and can say they were seeing smoke when it did it, or clean out the exhaust?

So my buddy who was there says he thinks that there might have been white smoke but he wasn't really paying attention to it. I just filled up my tank before I got to the strip so I know it wasn't low on gas.

 

[D.Hearne]

Let me guess, you uncorked the headers at the strip ? Thru the full exhaust on the road ?

 

[70grande]

Let me guess, you uncorked the headers at the strip ? Thru the full exhaust on the road ?

Nope, it wasn't allowed, I ran the exhaust thru the mufflers, it sounds good enough for me anyways, I have spintechs on it.

 

[blown65]

So my buddy who was there says he thinks that there might have been white smoke but he wasn't really paying attention to it. I just filled up my tank before I got to the strip so I know it wasn't low on gas.

I would be looking at something with the fuel system IMO. Check your float levels would be a good start. Kinda odd at 40mph or so it shows up. I could see it close to right off the line. Not sure where your shift point is in relation to that issue, but if its close try shifting early. Really need some video.

 

[67efivert]

check floats and fuel delivery ov launch fuel moves around alot and could be drawing air

 

[70grande]

Ok so a couple of you have suggested I check out my float level. I know where it is and how to adjust the level, but I dont know how to tell if I want it higher or lower. Anyone want to explain?

 

[coolblue65]

check your fuel filter too

 

[70grande]

check your fuel filter too

I just put in a new fuel filter a couple weeks ago. I think it might be my tranny... When it goes into overdrive, it sometimes fails to shift up into the next gear, instead it just lets the engine rev all the way up and then it starts the cutting out and wont stop until I put it in neutral and rev it through once. It just pisses me off cause I've had the tranny rebuilt twice already, I though C4's were supposed to be beastly.

 

[blown65]

I just put in a new fuel filter a couple weeks ago. I think it might be my tranny... When it goes into overdrive, it sometimes fails to shift up into the next gear, instead it just lets the engine rev all the way up and then it starts the cutting out and wont stop until I put it in neutral and rev it through once. It just pisses me off cause I've had the tranny rebuilt twice already, I though C4's were supposed to be beastly.

They are if they are good transmissions. I have over 200 pass in the 10's on mine right now and it doesn't flare at all.

Guessing you have a Holley carb, but unscrew the plugs out of it, and set where it starts to get gas out of them. The clear ones I usually set just a bit below half way.

 

[65ShelbyClone]

And, even when I let off the gas, it would stay in the disabled state, it felt/sounded like it wasn't even running on all cylindars. The only way I could get it out of this state was if I put the car in neutral (I have an A/T) and briefly put the car through full throttle, which it was perfectly capable of doing with no bogging down or poping or sputtering. After I did this, it would run like nothing had ever happened.

On my way home from the strip however, I was getting on the freeway and going from a rolling start of about 40, I punched it out and it slammed into overdrive and got all the way to 90 with no problems what-so-ever.

The only difference I see between these two situations is that it didn't run badly on the rolling start, which implies to me that perhaps fuel slosh is causing a problem. Low float levels could cause the jets to be uncovered by fuel. High float levels can also cause flooding.

 

[66forfun]

power valve issues maybe, sounds as if the problem happens when the engine is under load

 

[70grande]

power valve issues maybe, sounds as if the problem happens when the engine is under load

Oh ya, the problem is definitely under load, and all other times the car runs like a champ

 

[iskwezm]

off topic, but where did you run at?

 

[D.Hearne]

I just put in a new fuel filter a couple weeks ago. I think it might be my tranny... When it goes into overdrive, it sometimes fails to shift up into the next gear, instead it just lets the engine rev all the way up and then it starts the cutting out and wont stop until I put it in neutral and rev it through once. It just pisses me off cause I've had the tranny rebuilt twice already, I though C4's were supposed to be beastly.

How do you shift into overdrive with a C-4 ? C-4's aren't "beastly", in stock form they're quite fragile.

 

[stonecoldtx]

How do you shift into overdrive with a C-4 ? C-4's aren't "beastly", in stock form they're quite fragile.

Good catch and good point! If you have an Overdrive, you don't have a C-4!

Also, it sounds as though there might be fuel feed issues . . . perhaps not enough volume to the carb.

 

[70grande]

off topic, but where did you run at?

Irwindale Speedway in California

 

[70grande]

Good catch and good point! If you have an Overdrive, you don't have a C-4!

Also, it sounds as though there might be fuel feed issues . . . perhaps not enough volume to the carb.

Hmm interesting, I guess I never thought about that, I'll have to get underneath and figure out what has been put in there. I'm gunna start by adjusting the float's and see if that doesnt help.

 

[12sec67]

do you have jet extensions?