I believe I'm getting bleed through either in my injectors or my fuel pressure regulator diaphragm. One source says to remove the vacuum hose to check pressure, another said do not. Can someone clear this up for me ?

Thanks in advance...


And BTW...How long should the pressure hold with the engine off ? 5, 10 minutes ?

 

Well yes you definitely should check that no fuel is coming out the pressure regulator vacuum supply. Pulling the hose off to check isn't going to hurt anything.

It should hold pressure. I don't think there is a specific time interval. If everything is working properly it really shouldn't bleed off.

GD

 

A really good fuel pump and tight lines will hold pressure overnight but 45 minutes is acceptable. If it drops like a rock when you shut off the motor you have a fuel pressure leak.

Bleed through injectors meaning the injectors are leaking fuel is entirely different than a fuel regulator diaphragm leaking vacuum.

Injectors leaking fuel will give you engine run-on and run rich.

Fuel regulator leaking vacuum would raise the fuel pressure at idle and low RPM making engine run rich and wet the plugs - foul the plugs to.

Post your symtoms and maybe we can help..

 

The regulator doesn't lock on pressure when the engine isn't running. That's the job of the injectors, and the check valve in the fuel pump.

 

Thanks for the input guys...Yea...My 89 didn't start a couple of weeks ago...Turned over fast and fired one time, then the engine would just turn over and over with no fire. Let sit for a few minutes, and the same thing over again. Verified spark with tester on plug wire #1, and fuel by cracking the Schrader valve on the rail, but I have yet to pull a plug due to access through my headers. My next check though. Checked my TPS voltage, and it's in line. As I understand it, too high of voltage sends a flood signal to the ECM. Anyway I plan to put a gauge on the fuel rail, and check the plugs. I was just wondering what to expect if I see pressure drop on the gauge. Sad thing is these are new multitec, (OEM) injectors with about 2,000 miles on them.