Weird problem. CPS related?

Fletch124

2jz swapped!
Jul 17, 2005
1,282
0
0
Reno, Nevada
It all begins at the track. Went out to the drag strip to go play with some Hot August Night cars. Had fun despite a boost leak. I checked my coolant and oil after a few runs and my coolant was brown, there was "mud" on the bottom of the radiator cap. So i just went home and picked up some Prestone coolant on the way. This is where the fun begins. "Mud" in the coolant meaning the coolant got mixed with another color and its now bad. With the intention of flushing the entire system I went to pull the thermostat out and one of the bolts breaks off. Pull it all apart to the waterneck off which means I had to take the CPS out.

Fixed the broken bolt. Put it all back together, car doesnt start or run. So i played with adjusting the CPS for hours, couldnt get it right. Finally got it to start but had to keep my foot in it to keep it running. Set the timing in diagnostic mode to 10advanced. Outside of diagnostic mode the car jumps to ~13advanced. I adjusted the screw on the top of the throttle body 3.5 turns out and the car nows idles by itself, it was completely shut when i got to it.

This is where it gets weird. When the car is cold it wont idle by itself for ~30 seconds, then finally it will no problem. Once it gets warm it idles perfectly by itself, idle is smooth and AFRs are fine 14.7-16AFR. Step on the clutch from cruising and it will come down to idle speed no problem. Obviously from adjusting the screw throttle response is alittle off.

So what did I change or what happened that could cause this to happen? Ohh yea and no codes.
 

Fletch124

2jz swapped!
Jul 17, 2005
1,282
0
0
Reno, Nevada
I figured it out, a wire on the ISC harness was pulled out of the plug. Put another ISC plug from my na 2jz on and it works much better.
 

NeatOman

Never know enough!
Oct 5, 2006
233
0
0
Addison, IL
Fletch124;1102410 said:
Obviously from adjusting the screw throttle response is alittle off.

Are you talking about the TB?

That screw has nothing to do with throttle response. It is a Idle bypass screw to adjust the air flow when not on the throttle and should never be touched, unless someone has for you... then you have to find out how far in or out it goes. My car when i had it would have horrible idle when cold and ok when warm... in fact it would turn off after about 5 min. of warm up in really low idle or jump to @ 1k to stay alive. But i fixed that by tweaking it every three days as it takes time for the computer to adjust i guess. And i had a beautiful idle @ 650rpm-700rpm after two weeks of tweaking.