I have a 2000 New Holland 7610. When close to full throttle roughly 1700-2200 rpm it starts blowing air into the fuel tank through the fuel return line from the injectors. It doesn't do it at lower RPM's but only at the high end of the RPM range. The fuel from the return line looks fine until it hits the higher RPM then air bubbles appear. It has electric fuel pump that I've replace twice, had injectors rebuilt, new filters and I can't figure out where the air at high RPM's is coming from and nobody else knows either. It pressurizes the fuel tank and the caps (replaced 4 new ones) can't keep up with venting and spits fuel out of them. Anybody have a suggestion?
Can you post some pictures of the fuel system, especially the fuel injection pump?
Leaking injector or valve adjustment?
Depending on what inj pump u have, there’s a booster on the top cover that activates from the turbo.. it has a rubber diaphragm that blows out and instead of the pump getting more fuel, the turbo boost goes into the fuel tank.. It sounds as if u didn’t go far enough down the line in ur diagnosis.. The inj pump is A DELPHI..
That was exactly where I was headed.
I figured…
So it took awhile as I had to order a 5 star bit rather than a 6 but Mr.wrench and thepumpguy you were completly right!
So thanks for all your help as this has been going on for 6 years. Blessings, Ken
Glad you found the problem.