Is fuel coming out f the vacuum portal of the inlet fuel pressure regulator bad? I suspect it is. Furthermore... could this be a contributer to a low power issue I think Im having? Until today Ive had roughly 30lbs of pressure at idle on the outlet side of the fuel rail. It would drop 5lbs as the throttle was appllied. Today its just zero. It is appearent the regulator has failed completely. I think. Would a failing reg. cause loss of power.

 

And you would be correct


A failed regultor could cause low power, yes. Too much or too little fuel pressure...either one is a problem.

Cheers
DD

 

ding ding ding. Better power, better MPG, less of a chance for a fire. That will be a fun little fix.

 

Thanks guys. it always helps to get a little feedback. I spent the extra money and bought the Bosch reg from parts geek. Hopefully this will be the win sidescrollin suggests. ive read in other threads that the outlet side regulator is more or less a dummy set up. If so, why couldnt one just eliminate it altogether and join the fuel rail lines to the fuel coolant line?

 

No! It's the inlet regulator (RH side) that you can get rid of. The outlet regulator is the one that actually controls the fuel pressure seen by the injectors

Um......

We are talking about an HE V12, right? Just checking.

Cheers
DD

 

Fuel coming out of the vacuum port may mean the diaphram has cracked.

You can get rid of the inlet (left side) regulator. I've had mine off for over a year and taking it off makes no difference (on the V12 at least)

Thanks,

John
1987 XJ-S V12

 

The inlet regulator is the one on the *right* side of the engine !!


Cheers
DD

 

I really appreciate everyone's willingness to help. It was the regulator that first receives the gas from the tank that has a leak. It would of been cheaper for me to just connect the fuel line directly from the tank but what done is done there is a new RH rev on the way. The stoppage of fuel began there. I removed the fuel line that connects the rev to the rail with no gas movement. I then went back to the truck to check gas flow at the filter. I did follow the depresure procedure by removing the relay. Nonetheless I was treated to a gas shower in the trunk. Wife unhappy. The showers cause revealing that there was pressure that far. I was under the impression that the first regulator in line was the functioning one. This belief supported by the cost diff between the two during my search. The RH generally costing more then the LH unit. At this point I will just install my new RH unit and see what happens. Again, everyone's input is greatly appreciated!

 

I can't think of what they look like right now... are they really handed???

If you think about it the LH side one has all the pressure behind it, so it is dictating whether to let pressure build up or not, which is determining the rail pressure.

I guess the RH side is just letting it through to just double check that pressure its allowing past, it probably just makes everything a little more consistent. If it is leaking then it is losing pressure and not flowing properly, so it should still probably run a bit better.

if you did exactly what you said that isn't enough. Pulling the relay isn't doing anything to the lines. What you need to do is pull the relay or fuse and then start the car until it does nothing, so it pulls as much fuel out of the lines possible, but without any more being provided. This takes the pressure out of the system.

Been there, done that. Its a pretty high pressure shower, mine was right into my eyes.

 

Now that I'm thinking about it. (Maybe should of done more before the shower). If indeed the RH reg was the cause of blockage then the pressure relief procedure would not of made a difference. No fuel could of gotten to the rail to be used by the motor. The pressure soley existed between the pump and the regulator. Oops. Glad I still have eyebrows!

 

i thought you said it was just running poorly? I didn't know it was completely stopped up.

Either way, lesson learned. Always wrap a good sized rag around the hose you intend to pull on a injector/high pressure setup.

After having to mess with my pump and tank I got a set of hose clamps from harbor freight to hold them closed anyway

 

Duh!!! My bad, the useless regulator is on the right hand side.

Thanks,

John
1987 XJ-S

 

It occurrs to me that the RH unit does regulate fuel pressure but only during malfunction.

 

i didnt like the jag regulator so i added this return line SX fuel press. adjustable regulator.

works great i can change pressure,in couple minutes, right now i'm running 45psi(and readjust computor), higher pressure improves atomization mist!