Bad Idle Surge on '88 Fox w/Mods

wow, actually got the KOER codes this time:

Results:

21 R: Cooling Temperature sensor out of specified range or ECT out of range

94 R: Air diverter solenoid circuit fault

44 R: Thermactor air system fault

...is the thermactor air system fault for the smog controls? if so, i gutted all that **** with the A/C too. ???

There it is finally, KOER results!!
 
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car was borderline warm...will redo it right now to rule things out...how long u going to be online tonight- and thanks for the help with this. what do you think of the other codes? v/r dan
 
well, i redid the KOER test with a fully heated up car....still got the 21. see attached pic of how the ECT sensor is rigged up.
 

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also, just on my mind just now is that when i test the fuel pressure, i get the same reading whether or not the vacuum hose is on or off the fuel pressure regulator. is that normal? i have 24 lb injectors running at stock 39 psi fuel pressure.
 
Once vacuum is removed from the FPR, the PSI should go up about 5-6 PSI.


Is there not a spot on the back of the lower intake you could route the ECT sensor too? My Heater Core setup is just like yours(rubber hoses), but I put the ECT sensor in the back on My Cobra intake.

I dont see why it wouldnt work the way you have now. usually if there was an open in the ECT wiring it would throw a code 51, which a ECT circuit open code. So im inclined to think the wiring is fine as is.
 
wow, i am dumb, you can't have vacuum with the engine off, so now i did my fuel pressure with the engine running and low and behold, makes about a 6 psi delta when you put on or take off the vacuum line. so now the fuel pressure is for sure set right, but car is still having problems. sorry about the blunder!!