Maybe a thought from left field but does the carb have a fuel adjustment on it? It could be opened to the rich side if it does. Just a thought, beatr y head against the wall over one with similar issues and found carb was adjusted wrong.
I do not have a WC gauge, not familiar with the acronym N. am or EC. The regulator that was on the truck originally is long gone before my time. In addition, this truck was a mess. The ECU was bad, the temp sensor was missing, the FCSV was cracked, the check ball and elbow were missing, the MIL bulb was removed, the plugs were incorrect and the wire set was junk. In addition, the thermostat that is supposed be on the LP regulator is long gone. So needless to say I am up to my ears in parts on this thing and I still have a coding truck. The only good news is that it really runs good
Hi LTRM;
The Cobra vaporizer - regulator that was OEM original, was it built for N. Am. use or was it built for EC use? Then the next question is, your "primary" fuel pressure is good, but the "secondary" fuel pressure spring that is in use with the replacement vaporizer - regulator, is it the right one? The outlet fuel pressure from the vaporizer - regulator is susposed to be 6 inches negative W.C. at idle and 13-8 inches negative W.C. at full speed. N. Am. built Cobra aren't interchangeable with the EC's.
the fuel control is verified as 100% functional, if I run the vacuum line to the LP regulator directly to the port on the mixer that supplies the FCSV, the truck is still rich. All lines are confirmed correct including check valve. The LP regulator has been swapped reusing the original cover, I tried a second cobra brand new same problem.
Does the lp regulator have a vacuum port and line hooked up to the bottom of the cover? This system uses a fuel control solenoid valve to apply vacuum to the regulator to reduce fuel pressure, you will need an oem converter. I have swapped covers but service information says there is no rebuild kit for this converter so there must be something different from a model J or Cobra regulator. I would put on an OEM regulator, check the duty cycle of the FCSV, and check vacuum line routing.