Very low output voltage to TPS from ECU

I should 5V to TPS from ECU but read about 0.028 V.
From 2 different ECU.
1988 HE 5.3 V12.
Verified continuity of wire but did not check for grounds.
Also 0.028 V at CTS.
Car runs w/o TPS plugged in.
Fuel cut out periodic w/ TPS plugged in.
Running rich per A/F ratio meters.
?

It sounds like your wiring harness is failing. Hopefully it’s at an easy to reach location.

kind regards
Marek

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Disconnect the Ecu plug, connect a test lamp between the 5v contact and Batt + and it shouldn’t illuminate. If it does you have a Gnd short.

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Yes you are both right.
Thr un from TPS to CTS got under the intake manifold and crushed to the cylinder head.
This may help several problems.
I knew i had high udle and COULD NOT FIND LEAK with listening hose ir oropane tank.
Now I can fix.
Thanks.

It’s probably running rich because the coolant sensor is being interpreted as being very cold. It’s resistance ought to be low at full working temperature and very high if cold. If the harness is frayed enough, then it is simulating a very high resistance and the ECU interprets that as “cold”, so it adds fuel over and above that which is needed.

The throttle sensor will control fuel enrichment when accelerating, so it might be erratic or sluggish in responding to a rapidly changing throttle opening.

kind regards
Marek

I can try supplying 4.5 V from 3 AA cells and see if this changes anything.
I installed A/F ratio meters off the O2 sensors.
The motor mostly runs lean. Lean on cruise, idle too. If I play with throttle on cruise I can get it to run between rich and lean.
So it is NOT running dead rich.