3rd eh SCV

[Hammerhead800]

I have a John deere 4044r that I just installed a 3rd eh SCV on. It operates extremely slow and doesn't build any pressure. If I actuate the 3rd SCV and another SCV at the same time the 3rd SCV will operate at normal speed and builds pressure.
Any ideas as to what might be causing this problem?

 

[jenkinsph]

How is it plumbed in?

 

[Hammerhead800]

It is a factory eh SCV. It bolts right on to the end of the 2 spool loader valve thus adding the 3rd. This 3rd eh SCV has 3 ports on the mounting face that match up with 3 ports on loader valve . It has two other ports for the supply lines to a cylinder.