Stock Fuelpressureregulator Vacuum Source

[MopàrBCN]

Hi,

Recently I got new injectors and today I figured that the vacuum line from the stock fuelpressureregulator was missing so obviously they have forgotten to put it in.

So far no problem. Suppose I tap into the manifold or throttlebody source and connect a line.

My question, what happens, if it is not hooked up. What problems could occur?

Thanks for the enlightning!!!

[chilort]

The fuel pressure does change with vacuum and boost.

At idle without the vacuum source, the rail pressure is around 55psi, but when connected to the vacuum source, it drops to 45psi. In other words, you are likely running very rich while you are in vacuum.

The opposite occurs when in boost, from 0lbs on up, the fuel pressure regulator adds one psi for every pound of boost, so at 10lbs you should be running 65psi of fuel pressure. When in boost, you are going lean (generally not a good thing).

I run a log intake and the source for the vacuum for the fuel pressure regulator is different from the newer cars, so you'll have to wait for someone else to chime in on that.

Hope this helps.

[BadAssPerformance]

The fuel pressure regulator vacuum line should be plumbed into the vacuum port nearest to it on the intake manifold plenum.

[MopàrBCN]

THANKS to all, ok, this explains a couple of things!