Bad Fuel Pressure Regulator.

[NICAT]

Hi.
If manifold referenced fuel pressure regulator goes bad, does it usually cause rich mixture or it can also cause lean mixture ?
I do not exactly know how it works.(at least not in details) So can't figure out what tear, wear and loosen spring would result in.
Regards.

 

[andyd]

The usual mode of failure is for the diaphragm to fail and engine sucks gas into the intake port. If you remove the vacuum hose and gas trickles out it is bad.

 

[NICAT]

Originally Posted by andyd
The usual mode of failure is for the diaphragm to fail and engine sucks gas into the intake port. If you remove the vacuum hose and gas trickles out it is bad.


Thanks for reply

 

[eljefino]

Originally Posted by andyd
The usual mode of failure is for the diaphragm to fail and engine sucks gas into the intake port. If you remove the vacuum hose and gas trickles out it is bad.


And when it does this it runs mega super rich, sometimes even looking like it's shooting liquid gas out the exhaust on a cold start.

My mazda b4000 (ford based) did this.