90 TII Issues after rebuild
 

Now has Rtek1.7 with 725 secondaries, Full Racing beat exhaust, and smog pump removed.

Idle Issues, I have disabled the thermowax. Both throttles are closed upon their stops. Added pressure by hand has no effect. When warmed up, idle is at 1500. I can lower rpm to 750 by momentarily removing a vac hose(AWS). It will stay at 750 until the throttle is moved. Then it will return to 1500. When driving it will sometimes return to either 750 or 1500. BAC screw has input when at 750. Lower/front TPS set at 1K(.8 volt) and has an even sweep to 5.2K.

Timing, Set when at 750RPM. Angle sensor against front stop, still 2 degrees more advanced than spec. If I move to the next tooth, it will not be with in the stops. Timing advances properly.

Stock Boost Gauge, Not operating. Moves slightly at the bottom of range when starting.

Thanks very much.

Are you sure you dont have a vacuum leak? How much vacuum are you pulling with the throttle plates closed to their stops?

10inHg at 750rpm
16inHg at 1200rpm
There could very well be a vac leak or something crossed but I replaced most all hoses with new. It acts as if something switches when it decides to go to 750 idle RPM.
Seems to be running great otherwise, but I'm still easy with the break in. THANKS for any and all responses!

It's always worth going over the vacuum stuff again. Vac leaks can even occur around the fuel and oil injectors, bad gaskets and o-rings, and not just the vacuum hoses.

Another thing to check is with the throttle sensors. I know you have adjusted them, but give this idea a try. When the engine is idling, try pushing in on the adjustable sensor further than what it is adjusted for. If this causes the idle to drop to the lower rpm range, let us know. You might have electrical gremlins.

Someone correct me if I'm wrong, but I'm pretty sure you should be pulling around 18-19 inhg at 750. I'd bet on a vacuum leak.

Used a plumbers torch and couldn't find any vac leaks. Also moved the plunger on the front(lower)TPS. It did effect idle if pushed all the way in(0.3Kohm).
I tried; screwed TPS(a bunch) to get 1 volt-1.3K. As stated above, it was 0.8v-1K. No change to the problem. Maybe 2 out of 10 times when car comes to a stop idle will go to 750. Thanks again.

Did pushing in on the sensor drop the idle down temporarily? Can you measure the voltage being supplied to the sensor? We're wanting you to see what is going on without adjusting the sensor. You are testing for repeatability and observing values assuming the sensor is already adjusted. This will let us know if there is something in the wiring or in the ECU.

Have a look at what voltages you should be receiving at the ECU on page F2-78 here.
http://www.rotaryheads.com/PDF/2nd_g...tems_turbo.pdf

I had some stuck secondary butterfly valves that were giving me a high idle condition. Worth checking out.

Thanks very much for the link. TPS input voltage on both orange and red wires are 5 volt. Volts and ohms increase and decrease smoothly throughout it's movement. Yes throttle shafts move smoothly and are against the stops when in this high idle condition. Any other ECU inputs that raise RPM? Thanks

https://cimg8.ibsrv.net/gimg/www.rx7...98f6da5dad.jpg
But did you check the secondary throttle blade stop, which is controlled by the thermowax? You could also have a stuck thermowax.