Our tanks have no baffels so it sloshes around and doesn't pick up the fuel when it gets low.
low fuel level = stumbling?
Thread Starter
Intermediate
Joined: May 2008
Posts: 36
Likes: 1
From: Sonoma County California
low fuel level = stumbling?
Usually I fill up my gas tank around 1/2 tank . However, on a recent trip, the fuel level got down to 3 or 4 gallons, and the engine started to stumble badly. Filling up the tank solved the problem and the engine ran fine again. I tried testing it again , and at about 3.5 gallons left, it started stumbling again.
It acts exactly like it did a couple of months ago before I had all of the injectors replaced. And, as I said before, with a full tank down to 3 or 4 gallons, it runs perfectly. Does anyone have any ideas why this is happening? Thanks!
It acts exactly like it did a couple of months ago before I had all of the injectors replaced. And, as I said before, with a full tank down to 3 or 4 gallons, it runs perfectly. Does anyone have any ideas why this is happening? Thanks!
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Fuel starvation. This topic has been beaten like a rented mule.
Pull fuel pump assembly and ensure the sock isn't twisted or misaligned. Also make sure the fuel pump is fully seated on the sender assembly.
Pull fuel pump assembly and ensure the sock isn't twisted or misaligned. Also make sure the fuel pump is fully seated on the sender assembly.
Team Owner
Joined: Aug 2005
Posts: 34,988
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From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
There got to be something wrong. I can drive my Vettes with less than 1 gallon of gas and unless I don't take
a sharp turn all runs smoothly. 3-4 gal of gas in the tank should not produce any hesitation.
This topic has been discussed here before, and these Vettes have a fuel sender problem. How do you know you have 3-4 gallons inside the tank? I trust my gas gauge because I opened the tank and manually measured the capacity line-by-line. I calibrated my sender to show two lines/reserve light with two gallons left in the tank.
There is a splash guard there, the pump sits inside that compartment.
a sharp turn all runs smoothly. 3-4 gal of gas in the tank should not produce any hesitation.
This topic has been discussed here before, and these Vettes have a fuel sender problem. How do you know you have 3-4 gallons inside the tank? I trust my gas gauge because I opened the tank and manually measured the capacity line-by-line. I calibrated my sender to show two lines/reserve light with two gallons left in the tank.
Thread Starter
Intermediate
Joined: May 2008
Posts: 36
Likes: 1
From: Sonoma County California
Frankly, that's also what I was thinking. The previous owner said that he replaced the fuel pump, but since I've had to fix everything else he said he fixed, I'm not surprised :-)
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Safety Car
Joined: Aug 2009
Posts: 3,752
Likes: 278
From: Melbourne, Victoria, Australia
There got to be something wrong. I can drive my Vettes with less than 1 gallon of gas and unless I don't take
a sharp turn all runs smoothly. 3-4 gal of gas in the tank should not produce any hesitation.
This topic has been discussed here before, and these Vettes have a fuel sender problem. How do you know you have 3-4 gallons inside the tank? I trust my gas gauge because I opened the tank and manually measured the capacity line-by-line. I calibrated my sender to show two lines/reserve light with two gallons left in the tank.
There is a splash guard there, the pump sits inside that compartment.
a sharp turn all runs smoothly. 3-4 gal of gas in the tank should not produce any hesitation.
This topic has been discussed here before, and these Vettes have a fuel sender problem. How do you know you have 3-4 gallons inside the tank? I trust my gas gauge because I opened the tank and manually measured the capacity line-by-line. I calibrated my sender to show two lines/reserve light with two gallons left in the tank.
There is a splash guard there, the pump sits inside that compartment.
I have cable tied the container to the fuel pump/bracket to help the situation but getting another tank with the container still secured is the best way. I have tried all sorts of adhesives without luck.
Thread Starter
Intermediate
Joined: May 2008
Posts: 36
Likes: 1
From: Sonoma County California
I'm not using the fuel gauge to check the level. For example, the last time it stumbled, it took 16.5 gallons to fill the tank, leading me to believe that there were 3 and a half gallons left.
Thread Starter
Intermediate
Joined: May 2008
Posts: 36
Likes: 1
From: Sonoma County California
I'm absolutely agree with everyone that fills their tank at half a tank or so. It was only by accident I discovered this problem. If the solution is to always fill it up at half a tank, I can live with that :-)
Thread Starter
Intermediate
Joined: May 2008
Posts: 36
Likes: 1
From: Sonoma County California
Been there the plastic bucket that the pump sits in is glued to the tank and mine had come loose, even with a gallon or two of fuel it will starve the pump when going around a corner or heavy acceleration.
I have cable tied the container to the fuel pump/bracket to help the situation but getting another tank with the container still secured is the best way. I have tried all sorts of adhesives without luck.
I have cable tied the container to the fuel pump/bracket to help the situation but getting another tank with the container still secured is the best way. I have tried all sorts of adhesives without luck.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
I think it would be worth your while to double-check his fuel pump install. The C4 pump lifts out of the top of the tank. Very straight-forward. I wouldn't be surprised if he has the sock wadded up on there.
Team Owner
Joined: Aug 2005
Posts: 34,988
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From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
The C4 tank's capacity is 20 gal. If you take an empty tank to a gas station, the nozzle with release around 18+/- gallons. I don't know why, but it happens. I think is the new BS environmental green stupid BS nozzles gas stations have now.
The only way for you to be 100% is opening the tank, inspect the fuel pump components, and calibrate your gauges with a 2 and 5 gallon red containers.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
I got bad news for you.
The C4 tank's capacity is 20 gal. If you take an empty tank to a gas station, the nozzle with release around 18+/- gallons. I don't know why, but it happens. I think is the new BS environmental green stupid BS nozzles gas stations have now.
The only way for you to be 100% is opening the tank, inspect the fuel pump components, and calibrate your gauges with a 2 and 5 gallon red containers.
The C4 tank's capacity is 20 gal. If you take an empty tank to a gas station, the nozzle with release around 18+/- gallons. I don't know why, but it happens. I think is the new BS environmental green stupid BS nozzles gas stations have now.
The only way for you to be 100% is opening the tank, inspect the fuel pump components, and calibrate your gauges with a 2 and 5 gallon red containers.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
I do this and go by mileage. The gauge is somewhat accurate but not 100%. I never race my car under 1/2 as fuel starvation is a issue on C4's. It has been well documented.
Instructor
Joined: Nov 2000
Posts: 179
Likes: 2
From: Detroit Area
Before I replaced the fuel pump, I never had any problems with stumbling. Right after I replaced it, it started, when down to a 1/4. I took pictures during the removal, and when I installed it, I set the sock perpendicular to the small baffle, as in the pictures I took. It did not make sense to me, but that was the way it came out. When the stumbling started, I pulled the pump out and turned the sock parallel to the baffle, but no change. It is still stumbling. It is a NAPA pump. I used it, instead of a GM one, because all of the mechanics I know said NAPA’s Chinese fuel pump was no worse than everyone else’s Chinese fuel pump.