head scratcher

[WhatAmIDoing]

Have you jumped the fuel pump relay, just to rule that out? What is the fuel level in your tank? I've had problems with starting in the past when below 1/3 of a tank. Sometimes venting the gas cap helps. I think you should be holding more fuel pressure at the rail than that, as I have enough pressure to fill a few shot glasses after sitting for 48 hours.

[shegarty]

Are the fuel line connections good at the fuel pump?

The fuel lines coming from the pump looked in good condition when the pump was changed. Both lines came off without any problems and seated well on the new pump assembly.

[shegarty]

Have you jumped the fuel pump relay, just to rule that out?

When I replaced the fuel pump I installed a new fuel pump relay as well just to rule that out - it hasn't seemed to make any difference.

[WhatAmIDoing]

Have you jumped the fuel pump relay, just to rule that out?

When I replaced the fuel pump I installed a new fuel pump relay as well just to rule that out - it hasn't seemed to make any difference.

When my spare fuel relay went bad soon after it was installed, I went through 2 more KAE relays before finding one that worked.

[RickHaleParker]

but it would not explain the time sensitive nature of this problem.

I'm looking at your numbers. If you start off with 10+ psi you don't have a hard start. However when you started off with 0 PSI you had a hard time getting the first 10 PSI, Once you got to 10 PSI it took off. Why is it so hard to get the first 10 PSI .... ?

You might want to do a recap by publishing a list all the parts you have changes and everything you have done.

[shegarty]

but it would not explain the time sensitive nature of this problem.

I'm looking at your numbers. If you start off with 10+ psi you don't have a hard start. However when you started off with 0 PSI you had a hard time getting the first 10 PSI, Once you got to 10 PSI it took off. Why is it so hard to get the first 10 PSI .... ?

Both tests so far started out with an initial reading of 0psi at the rail. In the situation where it sat for approx 15 hrs it built the first 10 psi very quickly after turning the key to pos II. Then when starting it built the remaining pressure up to ~38psi quickly as well starting within 1sec at most.

Today, after sitting for almost 22 hrs it was again reading 0psi at the rail initially. However, when I turned the key to pos II the pressure built much more slowly and stopped around 4-5psi. Then when starting the remaining pressure was also slow to build taking 4-5 secs. The engine cranked during this time and then fired up when it reached ~38psi.

[shegarty]

Recap on parts changed and steps taken so far:

Within the last couple of weeks:
Fuel pump and new OEM relay
Fuel pressure regulator and associated vacuum lines
Replaced completely corroded main engine ground
Cleaned contacts from IDM to posts on coil
Swapped MAF for a known good unit (not tested but was on vehicle previously)

Prior to this:
cap and wires
ECT
cam sensor
cranks sensor
fuel filter

[shegarty]

Anybody have any ideas??? Is it possible that the new pump assembly has a faulty check valve? I am going to see if I can pick up a check valve tomorrow and install it if it ever warms up.

[RickHaleParker]

Inserting a check valve in the fuel line would, at the least, serve as a diagnostics tool.

[shegarty]

Inserting a check valve in the fuel line would, at the least, serve as a diagnostics tool.

From what I have read the best place to do that is just after the fuel filter?