Quick question... Is it possible for the fuel pressure test port to get clogged? I'd much rather hook my accurate fuel pressure gauge to the port in the front of my engine than try to read the probably inaccurate gauge on the AFPR which is mostly hidden by my upper plenum (which requires unbolting from the bulkhead to read ). Problem is that the last time I tried to use my gauge, I couldn't get a reading from the test port while I had a reading on the FPR gauge, and I know my pressure gauge is good as it's been used several times now.

Anyways, if it is possible for the test port to get clogged, how do I clean it out?

 

If you push the needle on your test port and you hear no air being bled off then maybe there is no pressure.?

You can test the fuel pressure using scope analysis. You can attach the scope trigger to a ignition wire, attach amp clamp to jumper wire on fuel pump fuse and finally use a fuel pump transducer on the fuel rail. I have never used this method but it seems to be a easy way to test the fuel system. 1A per 10psi of fuel pressure.Low pump speed with high current draw indicates restriction is downstream of pump, and high pump speed but low current draw indicates restriction is before pump. I haven't used this method for testing and only have experience by the notes that I took. If you are interested in this method I suggest educating yourself on using a scope to test the fuel system. Don't just take my word on this

 

You should be able to take the valve insert out with a tire valve stem tool. Same tool can be used for the A/C access port valves.

The tip of the tool is hollow with two notches cut across the end. The notches engage the flats on the valve insert.

For an example search for this at your favorite auto supply:

Longacre Racing 50272

RBob.

 

That's one thing I was wondering. So the valve is basically a tire stem valve? Do you know if they're interchangeable as I have 2 spare tire valves? I already have the core tool.

The thing is that the gauge hooked to the test port is showing NOTHING when the INLINE gauge on the FPR IS showing fuel pressure. And the engine runs (or it will run again when I get the fuel pump I ordered a full 2 weeks ago). I will double check the gauge (I've had issues with it previously but not the last time I used it before I had it hooked up to the test port on the 3100 rail) and then I will pull the core out of the test port and make sure it's not clogged.

I'd rather use the pressure gauge hooked to the rail as opposed to the one on the FPR for 2 reasons... 1, it's easier to see, and 2, it's more accurate where I need to reset the fuel pressure (45 PSI).

 

I haven't pulled the core out of a 2.8 or 3.1l port, but have pulled out others with the tire valve stem tool. Yes to it being just like a tire stem valve. The only thing would be the type of sealing material used. I have no idea if ones made for tires use a material that is OK with fuel.

On the FP gauge, make sure that it has a nub to push in on the valve. I use a length of A/C manifold hose between the access port and the FP gauge. One end has the nub while the other doesn't.

RBob.

 

The test gauge (Actron sold at Advance Auto) has a brass pin which is retained by some sort of rubber sleeve to push on the schrader valve. For some reason, the pin has come out of the valve connection before and I have had to push it back in a couple times now. I have been keeping the adapter (for smaller test ports) in the connector to help keep the pin from falling out when stored.

Since I can't do anything else without the fuel pump I ordered 2 weeks ago and hasn't shown up yet, I'll remove the valve core from the test port and make sure it's clean along with the bore it's installed in.

 

Another question...

What size are the external threads on the test port and can I possibly get a 90* adapter for it? I can't get the pressure tester on the port because the upper plenum is in the way... Stupid 3100 parts .

:edit: In case you're wondering, I had originally set up the pressure gauge on the test port without the upper plenum installed...

 

test port on my 2.8 has a cap...

 

-4 AN fits the port, also an R12 refrigerant hose/fitting fits.

RBob.