CallawayOwnersGroup.com

Hello all,
I am starting to think I have the dreaded c6 fuel pump crack. I have long cranks at start and smell gas. I’ll be doing a fuel system leak down test later today.

Anyway, if I’m replacing the fuel pump do you have any suggestions on something better to replace it with? I have the stock pump with magnavolt right now. Is the Kenne Bell boost a pump and lingenfelter replacement fuel pump a good plan? Or something else? The new boost a pump has a transducer for boost pressure measurements I believe…. Does that fit in the same location as the boost reference tube on the car now?

Any important insight for me?

Thanks,
Justin

Callaway has a stock pump for sale on eBay right now. Username: fastervettes

I checked that pump out. That’s a stock Chevy take out pump. I’m hoping to avoid the stock pumps due to the high failure rate on the plastic elbow. I’m also looking at dealing with the magnavolt fuel controller due to the fact that it appears as though it will fail at some point in time.

-Justin

I think you can sub in a Z06 pump and eliminate the boostapump. 89x2 can verify

What is the fuel pressure?

SurfnSun wrote: ↑Sun Nov 28, 2021 4:53 pm I think you can sub in a Z06 pump and eliminate the boostapump. 89x2 can verify

On the SC560/SC580 cars, I believe the spec for most, if not all, was a stock pump + Magnavolt.

On the SC606, it was the Z06 Pump + Magnavolt

On the SC620/SC652 cars, it was a specially built Callaway pump, no boost-a-pump

I finally got caught up with work and am working on the Callaway today. Here is a video of my fuel pressure testing. If anybody has any insight I would appreciate hearing it.

https://youtu.be/WFf3lo1HEFk

Thanks,
Justin

On the Corvetteforum it was suggested that the fuel pump prime delay or minimum fuel pressure before crank may be set incorrectly in my tune. Does anybody think that’s a possibility? It would be the time that Callaway put in the car.

The way the pressure drops instantly to zero upon shutdown makes me think it’s an issue in the pump.

-Justin

Rudevette wrote: ↑Mon Jan 10, 2022 1:11 pm On the Corvetteforum it was suggested that the fuel pump prime delay or minimum fuel pressure before crank may be set incorrectly in my tune. Does anybody think that’s a possibility? It would be the time that Callaway put in the car.

The way the pressure drops instantly to zero upon shutdown makes me think it’s an issue in the pump.

-Justin

It's not the calibration. No way, not unless something was changed. Now something mechanical, I'd go with that.

I'd call and ask Scott @ Callaway on how to bypass the magna volt to verify pressure drop is due to that - I had something similar with fuel pressure loss on the SC580 and proved it with a paperclip.

I spoke with Scott at Callaway and he is helping me out. Here is another twist on this situation:

The receipts for all of the work done on the car came with it. The original owner (possibly the second owner...I'm not quite sure yet) still had the car on March 17 of 2017. It went to Dimmitt Chevrolet in Florida and states on the work order-
D C/S HE HAS A STRONG FUEL ODOR SMELL
CAUSE: SPECIAL POLICY
9900358 Evaporative Emissions Smoke and Flow Testing

At that time they replaced the fuel pump, an exhaust gasket and clamp, a lower control arm suspension nut, the fuel lines from the pump to the crossover tube in the drivers side tank, and the o-rings on the crossover tube.

The car has about 30,000 miles on it now. I can check the exact mileage when I get back to my shop later today. It should be noted that it still has a strong fuel odor, particularly after filling with gas. So it's quite a mystery.

-Justin

Very interesting. I will be following...

Do Corvette tanks have the check valves in the tank like other GM vehicles? Could that be a problem? Check your canister to see if it has gas that comes out of it when unhooked.

DA

It is my understanding that there are check valves built into the tank modules. Thank you for the tip on checking the vapor canister. I had not thought about that and will do that.

-Justin

The check valve can fail and create flow issues.

DA

Big problem then is I think there check valves in both tanks, correct? If so, how do I figure out which one is the problem?

So I isolated the fuel line from the tank by putting a manual shutoff valve in before the fuel rail. I ran the car and shut the valve off with the car running, then shut the ignition off. The fuel pressure dropped to zero immediately upon shutting the engine off. I have the following information on the fuel system:

http://www.hessh.de/Corvette/FuelTankSystem.pdf

Judging by this information it appears to me as though the pressure could leak down at either the right or left tank fuel pressure regulator, or the right side fuel tank check valve, correct? Considering the drivers side fuel pump was changed at a Chevy dealer recently do I just plain pull out the passenger side tank and change the fuel pump module on that side????


What do you guys think,
-Justin

What if the dealer installed it wrong?

DA

If check b both!

I think I’m just going to have to pull both tanks. That was my gut feeling but the horror stories on the internet had to hoping otherwise. Oh well.

-Justin

Make sure you replace both fuel level sensors while you’re in there…or the right tank at a minimum