Got a winner, Check Gage, no defects in fuel, temp or pressure gauges though. Flashes intermittently.

[corerftech]

Just finished a carb.HEI conversion on 2001 Explorer 5.0.

I had to drop the tank AGAIN and remove the pump, add a stainless siphon straw, frame mount a fuel pump. All wnet flawless.
Had to install a carb manifold, install a new Dorman T-stat housing (has a 16mm port for a coolant sensor and I utilized it), installed the old EFI gauge sending unit.
Had to cut, solder splice (NASA quality) and shrink tube/reharness the Oil Pressure sender wire.

So I have tampered with all three of the gauges that Check Gage are involved with.

I filled the tank for the first time since conversion. Note: the fuel gauge has never OVER indicated. Today it is WAY past F. This is a first and highly unusual and consistent with the intermittent CG flashing light which seemed to disappear as the ride preogressed today.

The Coolant temp is in middle and remians there, no full scale, no fluctuation.

The Oil Pressure is NOT falling below 6 PSI. I would hear rods knocking with how I have driven it today. Oil gauge is dead center and stable.

Now------ there is a ground strap from approximately the windshield wiper motor mount to the EFI intake manifold.
That strap broke during removal and it is the only wire not replaced during the carb manifold install- on my to do list.

I find it highly unusual that I have a CG light and my fuel gauge is uber full, but it is not behaving in accordance with traditional defects associated with cg light.

Anybody want to offer a guess?

 

[bobbywalter]

i dont remember if a 01 has separate sending units for temp....if it has two...you dont need the efi temp gauge unless the tcm wants it.

just use the gauge sending units.

gauge peg is wrong ground or wires backwards or the float jammed up when you installed it.

deepending on how you wired the gauges that may be the issue using pcm sender with cluster.

 

[corerftech]

Just one sending unit in service.
EFI uses an insulated two wire (isolated ground) for coolant temp to PCM. Gauge uses one wire sender.
I am only using the one wire sender.


I used a pipe dope for the sender, very little. Then I used anti-seize on t-stat housing and manifold bolts. Curious if there is a high resistance ground path forming for the sensing unit ground. Again, coolant gauge has no defect visually, it’s spot on.
The ground strap from intake manifold to firewall missing has been haunting me since tear down.
I’ll add the ground strap back tonight and see how it behaves.

I think it a huge stretch that I could insulate a manifold with 12 bolts well enough with anti-seize to create a sending unit ground issue (but maybe the pipe dope was the kicker).

 

[bobbywalter]

i usually use tape now, especially on switches so i can keep it off the first 2 threads and have had great luck so far. one of my universal style fan switches i thought had failed.....then failed again...and again.....turned out they were simply getting corrosion issues. tried copper base...no better luck...then went to tape. so far so good with the tape and those switches i have been using...

not saying it will help as this may not be an issue for you. just a new ettiquette developed by trial and error with modern parts.

there are also different voltage regulator scenarios over the generations and that could have been janked up. the fuel gauge being maxed is a clue. those are simple enough.