Need help quick!
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
Likes: 1
From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
Need help quick!
Hi all.
I was getting track time last night as I just refreshed my trans and I plan to race at Super Chevy this weekend.
Problem is this: First five runs went fine. Then the next three runs in a row, this is what happened.
Burn out same as always, stage the same as always rev launch at 1000 rpm. At the light I smash the gas as always, car lauches hard for about 3 tenths of a second picking front end up, then the engine just BOGS for about 2 tenths bringing the front end down, then it picks up and launches hard again, finishing the run with no problems going through the traps at 6000 rpm. FYI nitrous was not used at all.
Fuel pressure? Electric issue in regards to fuel delivery? Tank had same amount of gas as always too.
Where do I look/Start? Suggestions? I am taking it to a good friend/corvette guru tonight but suggestions as to problem will be welcome.
Thanks!
Matt383
I was getting track time last night as I just refreshed my trans and I plan to race at Super Chevy this weekend.
Problem is this: First five runs went fine. Then the next three runs in a row, this is what happened.
Burn out same as always, stage the same as always rev launch at 1000 rpm. At the light I smash the gas as always, car lauches hard for about 3 tenths of a second picking front end up, then the engine just BOGS for about 2 tenths bringing the front end down, then it picks up and launches hard again, finishing the run with no problems going through the traps at 6000 rpm. FYI nitrous was not used at all.
Fuel pressure? Electric issue in regards to fuel delivery? Tank had same amount of gas as always too.
Where do I look/Start? Suggestions? I am taking it to a good friend/corvette guru tonight but suggestions as to problem will be welcome.
Thanks!
Matt383
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
My guess is fuel delivery. It isn't a bad pump or a clogged filter, because they wouldn't have allowed you to finish the 1/4, well at all. My first guess is fuel level, but there could be an intermittant electrical problem in the fuel pump circuit. Or any other circuit, but *I'M* guessing, fuel. That is a classic low level fuel problem.
RACE ON!!!
RACE ON!!!
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
Likes: 1
From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
It's not low fuel. I had more fuel in it for testing than I do when I race 'cause I wanted to do a lot of rounds without adding fuel.
Must be elec?
Thanks.
Anyone else?
Matt383
Must be elec?
Thanks.
Anyone else?
Matt383
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
Originally Posted by Matt383
It's not low fuel. I had more fuel in it for testing than I do when I race 'cause I wanted to do a lot of rounds without adding fuel.
Matt383
Matt383
Originally Posted by Matt383
Tank had same amount of gas as always too.
RACE ON!!!
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
Likes: 1
From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
Originally Posted by CFI-EFI
Sorry. I merely took your word for it. Does anyone have the URL for the crystal ball forum? *I* need helpwith mine.
RACE ON!!!
RACE ON!!!
Thanks for trying to help, really.
All I was saying was that I don't think low fuel was the problem as I had the same I always run with (and a little more).
So what I'm thinking now is that it has to be in the fuel delivery.
Electric, low pressure, something.
Thanks again.
Matt383
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Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
[QUOTE=TheStef] water?
I doubt he does, either.
If you suspect fuel, regardless of the CAUSE, tape a pressure gauge to your windshield, and make a run. At least you'll be able to make a determination as whether to chase fuel, or to move on.
RACE ON!!!
Originally Posted by Matt383
Not sure what you are saying?
If you suspect fuel, regardless of the CAUSE, tape a pressure gauge to your windshield, and make a run. At least you'll be able to make a determination as whether to chase fuel, or to move on.
RACE ON!!!
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,905
Likes: 1
From: 2003 Points Champ Great Lakes Corvette Challenge; 2006/2007 Winner MSD True Street
Originally Posted by CFI-EFI
I doubt he does, either.
If you suspect fuel, regardless of the CAUSE, tape a pressure gauge to your windshield, and make a run. At least you'll be able to make a determination as whether to chase fuel, or to move on.
RACE ON!!!
If you suspect fuel, regardless of the CAUSE, tape a pressure gauge to your windshield, and make a run. At least you'll be able to make a determination as whether to chase fuel, or to move on.
RACE ON!!!
First off I want to say that you were right.
I went to my friend's place Thurs night.
Found a pinched vacuum hose and lose coil wire.
Tested fine after.
Friday went to Joliet, Rt 66 for the weekend.
First run...bogged down again!
Now keep in mind my fuel gage reads 1/2 full...same level I always race with.
Anyway, I added 6 gallons of race fuel.
Next run..went great!
Issue was the reason it tested fine is that on regular pavement the car launches level...smokes the tires.
At the track, the car launches harder pulling the front end up and causes the fuel to slosh back more.
Any way the culprit was a faulty fuel gage.. reading 1/2 a tank when there was actually less, causing starvation on launch.
So in effect you were right. I never would thought my fuel level reading was off. So I believe in giving credit when credit is due.
YOU WERE RIGHT!
Matt383
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
Yep! "G" forces caused by a lot of traction, and not enough fuel to keep the pick up covered. The gasoline gets pushed to the rear of the tank, with the same force as YOU do into the seat. After the initial launch, especially with the short loss of power, the forces aren't enough to keep the pick up uncovered. How much force and how long it lasts depends on the fuel level. *I* race with a full tank. I know it may cost me a tenth, but I get the max weight over the rear tires, and I never run out. Not that any of that matters with a Crossfire.
RACE ON!!!
RACE ON!!!