abstruse1

I just had a Z06 fuel pump installed on my 2011 GS as required by the E-force blower I installed. The pump was furnished by Edelbrock as part of their "599 hp." kit.

It takes about 8-10 seconds of cranking before the engine will start. What's going on?

I have a similar situation with a Shelby in which I installed an aftermarket in-tank pump. That case was attributed to the lack of a check valve (or other detail), not maintaining fuel pressure in the manifold after shut down. Apparently the stock pump does maintain rail pressure. So is this what's happening? Is this a typical situation when replacing the stock LS3 pump with the Z06 pump?

Sorta annoying!

Eric D

Have you talked with Edelbrock? If they supplied it I would expect they would most likely have the answer for you.

realcanuk

I have the same pump with my eforce and have no issues. I watched the install and it is far from simple. It sounds like possibly something went wrong there.

Greenstealth

Id assume there is some type of internal fuel leak. It would be very easy to have happen when doing a fuel pump install on these cars. Does it crank "fast" for the 8 seconds or so? If so, it probably needs to be pulled down and reinstalled.

DSOMC6

E-Force install requires dropping the fuel tank and upgrading the fuel pump? Good God man...Why not just add a BAP and save a days labor/$$.

JoesC5

549 HP version uses stock C6 fuel pump. 599 HP version uses Z06 fuel pump. Edelbrock feels that the Z06 fuel pump is a better long term solution then a BAP. So does GM.

wallyj

I agree that something is probably bleeding off fuel pressure when the car sits.

I had a leak one of the many times I took something in the fuel system apart and that is exactly how it behaved. My leak was easy to find since it was fitting and dripped on the ground.

If you look at the thread Motorhead47 posted about fuel pump installs you will see there is definitely room for error during the install that could cause a probelm like this internal to the tank.

Motorhead-47

No it is not typical! Sounds as if you have a fuel pump install error. Inside the crossover tube are a forward and return fuel line that support transferring fuel from the passenger side tank to the driver's side tank. There are about 10 o-rings, spacers and ferrels between those two lines and the crossover tube itself. If one of the o-rings on the forward high pressure line (it is the upper line of the two inside the connection) is out of place (install error) then your fuel pressure will bleed off quickly and cause hard starts due to lack of prime in the line.

You need to get a fuel pressure gauge on the system to verify this. When the car is shut down you'll see about a 10psi instantaneous drop in pressure and then it should hold. If the fuel pressure continues to rapidly bleed off then you are probably in store for a do-over on the fuel pump job.

My two cents worth

j_digi454

I have no issues with starting as well and I have the 599 kit.

abstruse1

I took the car back to the pump installer (Dallas Performance). We noticed that fuel pressure at rail dropped to zero immediately after shutdown. Not good. They pulled the pump, etc., saw no problem, and put it back together. That was yesterday (they give good service). So far, things good. Pressure holds at ~35 psi after shutdown. 

Motorhead-47

Hard start problem solved?

abstruse1

As far as I know from brief driving yesterday, the problem is solved.

gfox

I installed a new Z06 pump on my C6 and having the same problem as well. Is it imperative to use OEM O-rings? I replaced a couple of the yellow o-Rings from a kit matching up the sizes. They seemed super close to exact but now I’m wondering go if that barely imperceptible difference is causing pressure bleed while she sits. [Note: I have not filled both tanks yet. Wondering if filling the passenger tank helps prime the upper or forward high pressure line and would solve the problem.]