One for the CIS experts

[balleta]

Sometime ago I was having hard starting problems when hot. Did the ceremony of opening the hood, take out the air filter and move up the flapper every time to start it. Tired of that I changed the fuel accumulator and solve the issue.
Later the car went to the shop for some general maintenance and while there the fuel pump went out so they put on a new one.
Long story short now it has the same hot hard starting issue.
I solved it activating the cold start valve(7th injector) with a micro switch at the end of the throttle linkage. It activates putting the pedal to the floor with the ignition switch on. Works perfect.
Then, I found the new pump box in the trunk and by chance checked the part number and found it needs an external check valve. The original one had an internal check valve. I check it physically and does not have the check valve.
That explains why it regained the hot hard start issue.
Am I correct?

[PeteKz]

Short answer: Yes.

Longer answer: Do you have a CIS pressure gauge/valve setup? If not, get one. The loss of residual pressure would have indicated the problem too.

After installing the the check valve, remove/disable the micro switch, or you may inadvertently flood the engine.