74 2.0L, Running Very Rich, owner quite confused, need diagnostic help Options

[drumsticks2112]

Car fires without a problem, but idles quite rough, and runs very rich, so much so that when the it settles down to normal idles, it floods out. MPS was replaced with a used but tested one recently. When it was last running ( a year ago) it ran a little rich, but nothing like this.

As of now, the CHT is not connected. When it is connected, the RPMs jump up to 4000 and stay there. When the CHT is bypassed with direct grounding of the harness, the results are the same as with the sensor being disconnected.

I have no reason to suspect the injectors, FPR, Decel Valve, or the MPS.
Any and all advice is welcome.

-Todd

[r_towle]

Start at the beginning.
Remove EVERY vacuum line from the plenum, put vacuum line covers on every port so you have no vacuum lines hooked up.

Now hook up JUST the mps.
Start the car...see if that cures it. If it does, its one of the lines.
Re-install ONE line at a time to find the system that is bad.

If that does not work (you can still get it to idle high)
you have to look at what you did...
That is specifically intake runners, throttle body, and all gaskets that go with that.
Check the bottom of the plenum for a rust hole...use a flashlight into the hole to see if there is a new hole that is not supposed to be there.

I have taken out the whole intake and I clean the head really well, then put a little smear of RTV Copper or Black on both sides of the spacer when I bolt it back to the head...that needs to sit overnight before you start the car.
Clamp the large intake runner rubber tubes on both ends...all of them.
Then, see if it still does it.

Throttle body gasket (is it complete, no missing pieces...use RTV if you have to to ensure you have no leak there.)

TPS setup...use the pic below to set it correctly at idle.
Idle circuit is special in Djet and you need to activate it by setting the TPS correctly...its a no adjustable thing...basically there is only one right way to set it...its not a variable...use the picture below.

Turn the knob on your ECU to zero...start there.
Go up one click at a time and wait ten minutes of running between any adjustment there.

Replace the CHT. check for shorts in the wiring going from the CHT to the ECU (pinout on Banders site)

Many times you will find the old wires break and short out...so its a good time to check the whole wiring harness...
Its time consuming, but simple to do with an ohm meter.

Rich