I am baffled!! 95 blazer 4.3 CPI OBD1.

Symptom: Raw fuel smell at rear of blazer, both sides and fuel washing on passenger side with puddles. Also some puddles on the drivers side. Starts perfectly and runs great with very Poor MPG maybe 11 MPG. Very slight, maybe 50 rpm hunt at idle. Off idle up to 1500 rpm the engine will hunt more when not moving and foot steady on the peddle. My guess what because of the super rich condition the PCM is trying to adjust. Above 1500 no problems.

Spider: Less than 12 months ago replaced the spider. Pulled intake not leaks under 60 psi.

Nut kit was not needed no leaks under 60 psi. NO leaks today under 60 PSI.

Fuel pressure leak down test. Looses 20 psi in 20 minutes.
1. crimped off fuel delivery line and performed a leak down test. lost 20 psi in 20 minutes
2.) Crimped off return line. 20 psi in 20 min lost.
3.) Crimped both return and supply off. Lost 20 psi in 20 min.
4.) Pulled poppets out, to see if they leaked, and applied 60 psi. Lost 20 psi in 20 min.
5.) Engergized spider, got good delivery with no stud open poppet. No noticeable leaks at the fpr and no washing directly below it.
6.) Replaced fuel pressure regulator, cause I didn't not what else to do.
7.) Washing and puddling returned with raw fuel smell.
8.) I did find lower intake to head bolts that were lose.
a.) Not sure how that could cause extra fuel to be in the intake?

PLEASE HELP I AM LOST!!!!!!

 

When i replaced my spyder on my old '95, i had to also replace those 2 small plastic fuel lines that are under the intake as well. They rub together and create holes. I also noticed a couple pinhole leaks in the fuel lines on the top of the fuel tank that was spraying into the frame then pooling and flowing out of random holes in the frame and onto the ground which made finding the source kind of hard, lol.

 

Thanks for your ideas. I haven't noticed anything dripping from the blazer at all. I do have some rub marks on the internal fuel lines but I visually inspected them with 58 psi in those lines and no leaks that I could see. I also isolated the tank to make sure I knew it was the intake or the tank or pump. I feel pretty certain its in intake. I appreciate the idea and I will check the tank out just in case.

 

Maybe the filler neck has a hole in it or the vent is clogged. That could explain the gas smell.

 

How did you pressurize in step #3?

If your tests and results are accurate, the 3 steps that you described, narrow the problem down to the nut kit, and or the regulator. With no visible leaks from the poppets, it should hold pressure indefinitely.

 

What is a 'nut kit' ?

 

I pressured using the fuel pump lead that is energized to activate pump. Used a fuel pressure gauge to monitor pressure. I agree with holding pressure but it doesn't and I replaced the regulator using the same logic you stated.

 

You already know the poppets are not leaking, so,
To isolate the nut kit and regulator:
Activate the pump using the red pump prime lead.
While the pump is activated, restrict the pressure line and the the return line simultaneously. This needs to be done to bleed all air back to the tank so your leakdown test will be accurate.
EDIT: If you have fuel pooling in the lower intake manifold, either the spider lines, nut kit, or the injector housing is leaking.


LeWhite, this is the "nut kit". Both lines are inside the plenum and carry fuel to and from the injector housing. The service port is in the pressure line, just as it enters the manifold, visible in the image below.

 

I did restrict both the supply and return lines. See my original post. I observed the nut kit and the spider poppet fuel lines. I even completely disassembled the sided units hoping to find bad oring or crack. I found nothing. Inused the service pump lead to run the pump as I crimped off both fuel lines then watched the lines for 20 minutes and not a drop of fuel came out from anywhere. ???

 

I'm thinking about getting some fuel dye and then trying to see where the leak is. Has anyone tried that?