engine rpm surge. help needed.

[fixkick]

so no real updates.. was on my desktop pc so i figured id share a few pics. today i had a second (that turned into 6 hours) to check the ISC (or iac depending on the person) the thing that raises idle with electrical load and being put in gear... that thing. well.. i removed it from the vehicle, scrapped off the old gasket material that stuck to it. cleaned it really well with carb cleaner. went to put it back on and thought to myself "hey weren't you going to bench test this?" ok so first because i couldn't find jumper wires i used my DMM and checked ohms. just looking for any number... well my number was OL yep.. O frekin L.
this thing has spec, for homes, 12 ohms or about 1amp. (12 watts) (the 89/90 year was 6 ohms)
if that meter is working the coil is shorted, and if shorted that loves to burn the ECU transistor that drives it. oops. a rare failure for sure.
always use a 2nd meter , a fixed range meter us the 20 ohm or 200 ohm scale, fixed. see if its not 12 ohms or about. say 12 ohms +-20% )
if it is shorted, the ISC is useless
but if the ISC is burned up then how can it surge? (unless AFR is lean)



so then i scavenged up my jumper leads. applied 12 volts... nothing. not a damn thing. that 12vdc need a 1 to 2 amp power source, minimum
using an inline fuse as the FSM directs you to test things hot wired or a short coil put to a car battery the wire glow red hot and burn you hands.
this is all basic elect. safety that, I use current limited power supply (bench) to do that and not need a fuse.


ok the ISC motor is fried. so i get on the internet and call around $300.. yep. needless to say i spent the next 4 hours in 4 different junk yards. finally the last yard way in the back had a 94 4door kick. engine looked untouched! i snatched the ISC, the MAF, the TPS, and the intake tube baffle piece i was missing. was in a hurry.. i didnt even look inside! i need interior bit and do dads too. will have to go back. i tested the ISC with ohms, got a reading! sweet. 12 volts applied click! perfect. all of it cost me $25 total. epic!
so i tested my current tps, seems ok. i have .085k ohms (850ohms that) at closed throttle and 4.0v fully open. the one from the junk yard reads like .040k ohms (400 ohms) closed and 5.0v full open, this was an off the car test tho.,
i tested ohms on both maf sensors and they are equal. (ohms dont work here it is not coil of wire, only power matters and output voltage., it's and anaglo electronic sensors)

bought and used a can of maf spray on my original and reinstalled it. have not started the kick yet at all. will do tomorrow and see if my isc works and try to adjust the tps to get that surge out., oh so i took apart my old non working isc (which is "sealed") to see if i cant have the motor repaired... well turns out these dont use a "motor" but instead what looks like a field coil. not repairable what so ever.

The ISC is solenoid, some mechanics think solenoids are motors. if it has wire and move, it be motor , but you are correct it is in fact a solenoid.
we have the part dismantled in web site. in great details.
http://www.fixkick.com/IDLE-AIR/Slide_Sh...ge_12.html

how ever you be first to unwind a coil there, LOL


the problem now is will the ECU not be burned up. 58B70 ECU. (or 58B7x)

the transistor that blows is here.

Q101 (blows up) if ISC current goes to infinity, as they do shorted!
2SC2562 (still sold world wide) its bigger transistor to handling 1 full amp, if the ISC pins do not modulate (PWM) at 200 times a second, the ECU is bad.

http://www.fixkick.com/ECU/ECU-16v-92w.JPG