FGY33: TAC miscue and TPS codes?

[3Q Jay]

did the left vcg, ngk pfr5g11 and egr/tb/aac/upper plenum clean o' fest on the fgy33 over father's day weekend.no issues that i'm aware of from flawed re-assembly, started on the 3rd blade, good vac, smooth idle.noticed that the idle was much higher than before, seemed maybe not enuf slack in throttle cable, so i loosened a tad.adjused aac bypass (not with the consult 1 like laptop interface) to about 1.5 turns.problem 1: the TAC wants to push open the throttle. sometimes will idle in gear at 1250 rpm warm! pulling TAC vac hose relaxes diaphragm further (higher throttle opening). plugging back in the TAC vac hose sometimes brings it down to normal idle (air gap between tac plunger and throttle plate arm) and sometimes leaves it resting on throttle arm.problem 2: associated with the high idle, i get multiple TPS codes (1705, and two others --both are also TPS related, but cant recall them at the moment and i'm away from the car.

i had a brief run with the laptop interface (note was distracted and did not record AAC%), and the throttle voltage, mass air flow, o2 sensors, etc all behaved as expected. but i also did not trigger any codes during that run.

my thinking at this point is that when the throttle fails to close completely, the TPS codes trigger.

i cannot tell if some previous monkey has tried to adjust the set screw on the TAC throttle arm.

car runs to high standard otherwise.

ideas?

[elwesso]

my thinking at this point is that when the throttle fails to close completely, the TPS codes trigger.

agreed.. The TPS has a switch built into it too so that the ECU knows when the throttle is "closed" and its supposed to be in idle mode vs just off idle.. In my experience the best way to adjust the TPS is by finding that threshold between "on" and "off" idle, and adjust it so..

[miata007]

You may also measure the resistance of the TPS. See FSM for that.I've recently replaced my TPS as my engine scanner splits out 3 codes all related to it.

The symptom was, at times, engine runs at higher than normal rpm. Ex. normal 650rpm, when problem occur..runs at 1500rpm.

Please do a search on for miata007 and should find that link.

007

[3Q Jay]

Wes, the interesting thing is that the laptop TCS voltage read exactly 0.48v at hot idle when working good. i'm not sure that an adjustment is in order,although i'm not sure which TPS the laptop is reaidng and which tps the ECU reads (since there are more than 1)?

[3Q Jay]

007, i found your post from April, and the symptoms are identical.If you will indulge me, what exact part number did you replace on the TPS (I'm pretty sure there are at least 2 aqnd maybe 3 TPS on the fgy33).

[elwesso]

Could the secondary TPS be misadjusted?