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I have a jdm turbo series 4, all original. If anyone needs to know, the initial set connector is near the tps not the coil. The Japanese Service manual also says to remove the fuel cap first, then jumper set connector.
I had high idle and so removed upper intake. Cleared a blockage in the bac valve so the thermowax would operate. Wound the thermowax idle cam screw to the 25deg mark and set the fast idle adjust so primary throttle plate has .4-.5mm clearance. Dialed back the idle cam screw to just below the 25 mark as it was about 19deg here. Checked the primary clearance as the secondary throttle starts to open and it was within spec. Set the tps by holding the idle cam up, using ohms method so it was in the ball park.
re-fit the uim. Make sure the hose to the bac is out of the way or the omp rod will stick.
I then got it up to temp and it was idling high around 1100rpm. Jdm have a throttle adjust screw (tas) not a throttle stop and no adjustment at the bac. Removed fuel cap, bridged initial set connector and turned the TAS counter clockwise til idle was approx 750. Adjust the variable resistor rich til it was over 800-900. Then back down to 800 (was smoother than 750rpm) and call it good as if you adjust the TAS too far down the throttle linkage seems to stick sometimes. Removed initial set connector, put fuel cap in and I’m afraid to touch/check tps as it’s smooth now and it has a dead spot so that will need replacing once I can find one. Ordered some 1mm split pins as I broke one leg off, fingers crossed that’s small enough but it is holding. No more high idle except the obvious warm up and no more fluctuating while warming up.
just a bit of info that may help others with jdm fc 13bt.
Last edited by ben.farnath; Oct 1, 2023 at 02:48 PM.
Update. Ordered new tps from Blackhawk Japan. Pulled the old one off and this is what was going on/why I was running out of adjustment to get it up to 1k ohms.
I wound out the adjustment a random amount and put new tps on. Checked resistance while holding up fast idle cam and it was 1.01k ohms well that was lucky! Got it up to temp and idle was just below 700rpm. Reset it using the jdm procedure to 750 ish. Tps set to 1volt DC as I now had enough adjustment and check resistance it’s at 1.08k ohm. Checked dashpot while was at it and it is within spec adjustment. Smooth sailing! Just waiting on shifter bushings to turn up before I can drive her again, cannot wait!
