Help !! Losing power when cornering
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 45
Likes: 0
Help !! Losing power when cornering
I have a 1987 corvette and just installed a new motor in it, new factory fuel injectors, new fuel pump etc,etc. My problem is when cornerning, not in a racing venue just on the street I lose power like it's starving for fuel, I have to give it a lot of gas pedal then it picks up and starts to run ok until I have to make another turn either right or left it does it. On cold mornings it starts then dies a couple of times and sometimes it dies when warm at stops. Does anybody have any insight as to what could be causing this very troublesome condition? Any help would be greatly appreciated. Thank You and GOD Bless.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
How full is the gas tank?
On stock C4's it is fairly common for fuel starvation during cornering if the tank is about 1/2 full or less. It does not have to be on a track. On one of my favorite on ramps it happened to me several times. I corner fairly hard on the street, but not at racing levels.
On stock C4's it is fairly common for fuel starvation during cornering if the tank is about 1/2 full or less. It does not have to be on a track. On one of my favorite on ramps it happened to me several times. I corner fairly hard on the street, but not at racing levels.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
On my old '87, I would see some of the same symptoms when the tank was down to around a 1/4. But this was at autocross and track day events. Didn't really see a problem on the street.
Did you replace the fuel filter? Did you replace the "strainer" at the bottom of the pick-up? What is the fuel pressure? Hook up a gauge to the valve on the passenger side fuel rail and turn the ignition to ON but don't start the engine. You should see somewhere around 40-45 psi. If the gauge has a long hose, you can tape the gauge to the windshield so that you can see the gauge. Drive around and duplicate the problem. What is the fuel pressure when the stumble occurs?
You can "rent" a fuel pressure gauge at AutoZone (pay a deposit and when you return the gauge, you get your money back). The fuel filter can be a PITA to change but it's well worth doing. If your car also has a filter on the return line, change that one too.
Did you replace the fuel filter? Did you replace the "strainer" at the bottom of the pick-up? What is the fuel pressure? Hook up a gauge to the valve on the passenger side fuel rail and turn the ignition to ON but don't start the engine. You should see somewhere around 40-45 psi. If the gauge has a long hose, you can tape the gauge to the windshield so that you can see the gauge. Drive around and duplicate the problem. What is the fuel pressure when the stumble occurs?
You can "rent" a fuel pressure gauge at AutoZone (pay a deposit and when you return the gauge, you get your money back). The fuel filter can be a PITA to change but it's well worth doing. If your car also has a filter on the return line, change that one too.
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 45
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Baffle in fuel tank?
[QUOTE=kocoach;1593736257]All of those things have been checked out, we believe it may be somewhere a broken baffle in the fuel tank that when cornering without the assist of a baffle the fuel is allowed to move away from the fuel pump when cornering. We are going to check all of the aforementioned much appreciated suggestions over again as we are only human and may have overlooked something. Thank you guys so much the forum is the best.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
If you pull the fuel pump, you should see a sort of "box" at the bottom of the tank where the strainer would be located with the pump assembly installed. With the tank empty, you should be easily able to see it by looking straight down.
It's designed to retain some amount of gas to keep the pump providing gas into the line. Unless there is rust or corrosion inside the tank that could have broken down the box, it should be there and holding some gas.
It's designed to retain some amount of gas to keep the pump providing gas into the line. Unless there is rust or corrosion inside the tank that could have broken down the box, it should be there and holding some gas.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
Last edited by aklim; Dec 26, 2016 at 03:57 PM.
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Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
This is most likely a fuel pump problem.
The fuel pumps lose pressure over time and start to push less and less. If this is the original, Id think of swapping it for a new one.
Of course, filter, screens and such...
The fuel pumps lose pressure over time and start to push less and less. If this is the original, Id think of swapping it for a new one.
Of course, filter, screens and such...
Melting Slicks
Joined: Dec 2009
Posts: 2,236
Likes: 286
Get one of those holley fuel pump strainers. They call them hydramats.
https://www.holley.com/products/fuel_systems/hydramat/
https://www.holley.com/products/fuel_systems/hydramat/
Last edited by ex-x-fire; Dec 26, 2016 at 06:10 PM.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
Get one of those holley fuel pump strainers. They call them hydramats.
https://www.holley.com/products/fuel_systems/hydramat/
https://www.holley.com/products/fuel_systems/hydramat/
Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Spark or fuel..
Consider the act of a turn, what moves inside the engine compartment? The steering shaft, suspension a-arms, some g-forces....
What can shutdown the engine? Pinched line that closes when turning. Or ignition source? Loose or pinched wires?
Maybe setup up a FP gauge to monitor pressure when driving..
Consider the act of a turn, what moves inside the engine compartment? The steering shaft, suspension a-arms, some g-forces....
What can shutdown the engine? Pinched line that closes when turning. Or ignition source? Loose or pinched wires?
Maybe setup up a FP gauge to monitor pressure when driving..
Melting Slicks
Joined: Dec 2009
Posts: 2,236
Likes: 286
Nope, never tried one. I never looked at the price of them, but I'd get one next time I have the pump out.
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 79
From: Monroe OH
NCM Sinkhole Donor
Something else to check is your connections from the fuel pump to the the junction on the underside of the sending unit. Just pull your complete sending unit out and look at all the wiring and connections. I have had so many issues with the fueling system in my 91. It was autoxed so it was always cornering hard and if there was a weak point it would show up. Most of the time it would be easy fixes but sometimes would take some time to find. And most of the issues would be the wiring from the pump running up to the junction. Good Luck.
Burning Brakes
Joined: Nov 2009
Posts: 828
Likes: 103
From: Olney MD
Cornering and fuel starvation
I took the fuel pump out to see if the 'tray' had been knocked loose, since that was cited by others as a primary cause of starvation on cornering. The tray was right where it's supposed to be, and was not at all loose. If I'd thought about it, I think I would have replaced the fuel pump while everything was out, but I didnt. The starvation issue only occurred when I was lower than a half tank, so when I autocross, I fill it up before the event. Still, I'd like to solve the problem permanently.
Team Owner
Joined: Jul 2004
Posts: 28,472
Likes: 3,290
From: Hartford WI
I took the fuel pump out to see if the 'tray' had been knocked loose, since that was cited by others as a primary cause of starvation on cornering. The tray was right where it's supposed to be, and was not at all loose. If I'd thought about it, I think I would have replaced the fuel pump while everything was out, but I didnt. The starvation issue only occurred when I was lower than a half tank, so when I autocross, I fill it up before the event. Still, I'd like to solve the problem permanently.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The symptoms described are usually caused by a leaky connection between the fuel pump and the supply line to the fuel rail. When the leaky spot gets exposed to air by moving fuel, the fuel sprays out instead of going up the pipe like it's supposed to do.
Common causes are a short fuel pump that doesn't allow the pulsator to make the connection to the supply line. Another thing that can cause this is non submersible fuel line replacing the pulsator. Your fuel line might look like this:
Common causes are a short fuel pump that doesn't allow the pulsator to make the connection to the supply line. Another thing that can cause this is non submersible fuel line replacing the pulsator. Your fuel line might look like this:
