90 gst idle revs up and down

[fupkid]

I just got a 90 gst. The previous owner said the car would only be drive able with the mas unplugged. When I plug it in the car revs up and down and bogs down when I push the gas pedal. And when its unplugged its atleast driveable. Not the best but. The iacv looks like it was just replaced along with the tps.
the codes I got were 13 21 25 with the mas unhooked. I swapped in a new mas and it does the same thing. Any sugestions? Also by my coolent temp sensor for the ecu there is 2 wires hanging down and there both green with yellow stripe. Ones broke from the gauge sender and one from the ecu sender. How do I figure out wich go's where?

The tach also drops to zero under boost and comes back up when left off the pedal. I think I really have my work cut out for me.

 

[luisgil]

Vaccum leaks?

 

[fupkid]

I've looked all over and haven't seen anything. While the engine is running I can unplug the iacv and nothing happens it still acts the save

 

[DSM1G90]

ISC motor could be bad along with the ECU needs rebuilt. Should never unplug sensors with motor running for that can blow the drivers in the ECU which these above problems are the result.

 

[fupkid]

witch one is the isc motor?

 

[DSM1G90]

which one is the isc motor?

Unit is attached to the throttle body below the throttle plate linkage assembly (for us 1990 units-1991 and above mounted theirs out in front for easier access so the throttle body doesn't have to be removed "OH JOY!")-a cylinder looking device with four screws to mount it to the throttle body. Price for a unit is close to $200 bucks.

 

[fupkid]

Is there a bypass to get rid of this little demon?

the number on my ecu says mt193299 is this correct for a 90 gst

this ecu came up for a 93 eclipse gsx

how do i get this ecu to work in my car

 

[DSM1G90]

Correct MD is 128625 for a 90 turbo FWD setup.

 

[fupkid]

so can I wire my 93 ecu to work in my 90. Could this be why my car is acting up?

well i switched the wires and the car idles great now. i am getting a code 21 still and the cts is new. is there a way i can rewire this to the ecu?

 

[19Eclipse90]

Check continuity with your multimeter from ECU pin 20 to the two "green with yellow stripe" wires to determine which one is which. Whichever one has continuity is the one you need to hook up with your coolant temperature sensor.

 

[fupkid]

I've got it hooked up to the correct wire but its still throwing a code. I think the wire might be broken and grounding out.

 

[19Eclipse90]

If the wire is broken, a continuity test will tell you because it won't have continuity across it. Do the test from the wire in question to ECU pin 20 to find out.

 

[fupkid]

I decided to run two new wires to the ecu from the cts. Now she is a happy camper and no more cel.

Now I'll try to wire up a tach since mine is acting up after 5k. And install a boost gauge. Then the modding begins

 

[fupkid]

Does anyone know where I can get a tach adapter for my 93 ecu in my 90 eclipse?
I like the dsmchips external one but it says there out of buisness.

 

[fupkid]

Ugh wwent from 5th to 4th yesterday and now the clutch won't disengage.

 

[74runner]

With a friend pumping the clutch pedal, pull the fork boot and look in there to see of the throw out bearing is stuck or if some thing has broken.