LS3 cold start problem

[edcmat-l1]

When I didn't see a tune/log I was waiting for this...lmao

It comes in handy LOLOL

[edcmat-l1]

HZow long does it take to show good oil pressure? After priming the fuel pump for 2-4 sec. upon key on, I *think* that the ECU doesn't enable the fuel pump again until it sees "good" oil pressure.

If the rail is fully pressurized and the system has a functioning check valve it should fire almost immediately regardless of if the oil pressure is high enough to trip the sensor to activate the fuel pump. And being a swap vehicle it most likely does not have the feature you're talking about. Not a GMPP engine package.

[JimLev]

There is no check valve in the fuel system.
I took the regulator apart this morning just to make sure there wasn?t any crud in it. Looked fine.
While running its at 58. As soon as I turn the key off it drops to 44psi.
I?ll order a check valve.

Why can’t I post a pic? Is there a file size limit or do I need more posts?

[gtstorey]

There is no check valve in the fuel system.
I took the regulator apart this morning just to make sure there wasn’t any crud in it. Looked fine.
While running its at 58. As soon as I turn the key off it drops to 44psi.
I’ll order a check valve.

Shouldn't it drop to zero with no check valve?

[edcmat-l1]

So we're on page 2 now with no data log or tune file. E'ry body still guessin.....

[gtstorey]

So we're on page 2 now with no data log or tune file. E'ry body still guessin.....

This is the one that doesn't have HPT. I'm doing a lot of water system modeling at work today, so I don't have anything better to do between model runs.

[JimLev]

So we're on page 2 now with no data log or tune file. E'ry body still guessin.....

No HPT so no data log….that info was in post 1.
Just ordered a check valve, be here on Tuesday.

[JimLev]

Shouldn't it drop to zero with no check valve?

Probably more than you wanted to know….
It does go to 0 eventually. Inside the regulator the center of the diaphragm has a ball on it. That fits into a seat with spring pressure keeping it closed, not really a good seal. The fuel pump pressure pushes the diaphragm up, so when the pump shuts off the spring pushes the diaphragm and ball back down on the seat. The seat for the ball has a hole that goes to the return line to the tank.
I’ll put the check valve on the output of the regulator to keep the rail pressurized.

[JimLev]

Check valve is installed, didn’t fix the cold start problem.

[edcmat-l1]

Time to buy HPtuners so you can move on to the next step.