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All grounds clean & tight. I'm beginning to doubt everything & trust nothing including my meter.
No min/max settings though, just peak hold.
This is with engine off, 200 vlt AC setting:
For giggles, I started checking other vehicles handy, my mustang, 27+.
Neighbor's 2001 Lincoln 26, only my wife's 11' Escape shows zero (0 vlts ac) engine off.
I can tell the vref is spiking cause the individual fault codes are exactly what I feel when it acts up. Pretty sure the bang shifts with no code is the TPS fault.
Pretty sure the bang shifts with no code is the TPS fault.
I replaced the speed sensor and the MLPS in the ‘94 Bronco and I would still get the occasional transmission issue. The TPS eventually got bad enough to set a fault code. After that it seemed to be ok.
this is a excerpt, This test is used to isolate excessive resistance in the wiring leading to and from your load. To check the "hot side" of your circuit hook the positive lead of your Voltmeter to the positive side of your battery. Hook the negative lead of your Voltmeter to the "hot side" of your load. Operate the circuit and read the voltage displayed on your Voltmeter, I wonder if you could use VREF as your 'hot side" and monitor one of the codes your getting, and see if it shows you a peak. Excerpt came from our Misc/Electric Classic Broncos .com - Tech: Basic Vehicle Electrical Diagnosis for 66-77 Early Ford Bronco
... The TPS eventually got bad enough to set a fault code. After that it seemed to be ok.
The TPS is one of many getting an "above 4.67 vlts" code which is most noticeable when accelerating (trying to).
Check Engine light literally flickers to full illumination as you press the gas pedal & acceleration increases as it "catches up", then bang 1-2 shift.
Ease off on the gas, engine settles down, light goes out, 2-3 shift normal.
Thanks. I really let the diode in the fuse box get by me but I was looking a Haynes diagram & didn't think.
See below why I got distracted.
Here's the deal so far... The replacement harness as I said is 90+ % complete. It was cut, passenger side, just past the lighting stubs & after the inner fender grounding lugs at the battery.
I picked up the ending piece this weekend (O2 sensor connector, starter wire, AC pressure switch connector, alt exciter, etc.) that I'll splice in.
The yellow power cable with fuesable links I pulled complete back to the fuse box from the donor. I'll lay it on top of the existing bundle for now.
I know the engine side is golden, but one difference I've run into makes me want to double check some other things before plugging it all in & firing it up.
The original high pressure sensor switch harness (right side connector) has 2 wires. Every 5.0 & 4.9 including my 5.0 donor harness's I've looked at has only 1 wire.
I can't seem to drill down far enough to tell why.
So what diode lives in here (short, fattest, stubby harness at fuse box I think was going to C202):
All of my diagrams do not show the pressure switch with 4 wires, only two. The AC clutch diode/resistor is supposed to be located on the harness near C101. Electrically it does not matter where those components are located as long as they are in the circuit with the diode in the correct polarity. That diode/resistor pack is going to C101, connector on the driver side inner fender.
Or the mystery pack could be the brake warning diode/resistor that is taped in the harness near C202.....
Those are the only two diode/resistor packs that come to mind.
Let me stick with the pressure switch for now, the resistor for the brake circuit showed it's self finally.
Below is the harness that comes out of the firewall (connector on left) next to the blower exposed, with the stock 5.8 wiring (Right, purple-black/yellow, Connector 126?) & below is a 4.9 donor. (Red/yellow?)
This is the same connector in place on a 94 MAF 5.0 truck, single black/yellow wire.
What I'm trying to figure is the second wire path going in the cab through C202, or just what makes this different?
I believe that may be connector C106 based on the location description in the EVTM manual
In 1995 that circuit changes to this:
There is a different version for 4.9L CA emission trucks where they added a relay to dropout the compressor when commanded by the PCM
Why there is a purple wire on what I suspect is C106 when the manual shows that is done upstream before the A/C Clutch cycling switch via splice S153 is anyone's guess.
