Fuel Pressure Regulator
 

Hi everyone,
I'm new to the forum, and hope to use it alot.
I have a 1995 Blazer 4.3L that runs rough.
I have replaced plugs, wires,distributor cap,rotor,idle air control unit, throttle position sensor, egr valve,map sensor and is still running rough.
Decided to do a leak test, and determined "what I thought" was a leaky FPR.
Pulled the plenum off and found that the entire passenger side of the intake is CLEAN, no carbon, while the drivers side is black with carbon.....as it should be.
no fuel sitting in the bottom of the intake on either side. Did the fuel pressure key trick, and didn't see any leaking of any kind.
Not from the FPR or any from the two fuel lines going into the spider injectors. Pressure side or return side.
So, now I'm stumped.
If there are no leaks inside the plenum/ intake........what is creating the clean brass look, in the intake? Is there a chance the FPR is faulty without leaking? And if so what's cleaning the intake? Something is cleaning the inside of the intake, but I don't detect a leak. What's going on?
Can anyone help?
Cheers,
Paul

Welcome to the forum.

Have you performed the fuel pressure test in the sticky?

Do you have any codes?

Do you have a scanner with live data?

Has there been a compression test recently?

What did the plugs look like?

George

Have not done a fuel pressure test in the sticky. Don't know where or what the sticky is.??
Not showing any codes.
I don't have a scanner with live data.
Haven't done a compression test.
Plugs were black. Which tells me the engine is running rich.

Also, wondering what's cleaning the inside if there doesn't seem to be a leak?
Cheers,
Paul

You will find a procedure at the top of this forum in a sticky post to test your fuel pressure and most importantly the ability of the entire system to hold pressure. That will help you determine if you have a leak. That will not help you determine if you have an injector problem under normal operation, that's where a proper scanner comes into play. You can get good scanner function pretty cheap with lots of guidance here. You should start with fuel trims once you get set up.

George

Hey Paul, do you still have the top of the intake apart?

Yes I do.

Upgrading to the MPI would be an upgrade, and since you already have it apart...