ide problem and three diff codes

[jdub]

The TPS has two functions:
1) Signal the ECU when the TB plate is closed (IDL)
2) Determine TB plate opening angle to the ECU (VTA)

IDL is a simple switch...it's open or it's closed. Closed puts the ECU in idle mode. The ECU works on voltage not resistance...in the case of the TPS, 5 volts is supplied to Vc in the diagram (link below). Think of VTA as a volume control knob on a radio, as it moves higher on the scale, voltage increases. Voltage should vary between .1 to 4.2 volts as the TPS is rotated to full open.

http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=103

You might want to check VTA at the ECU to see what voltage is present. The TSRM outlines how to do it here and on the following pages:

http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=50
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=51

http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=55
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=56
(pay attention...you do not want to short the wrong terminals at the ECU)

ISCV inspection:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=107

Note how you can get the ISCV to move by grounding the appropriate terminals.

Here's how to test the fuel cut RPM:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=125

It occurs at 1600 RPM, not 3000. Basically the RPM should bounce between 1200-1600 RPM with IDL & E2 connected and the gas slowly advanced.

A couple things to check:
- Make sure the TB plate is full closed with the engine at idle.
- Since this is an '87, check the air bypass screw on top of the TB. It should be fully closed (screwed in). It is set that way from the factory, guys mess with it and cause all kind of problems.
- Block all air at the ISCV inlet from the accordion hose (plug the hose). The engine should die.

 

[Moy]

I had him over today, I was able to set the TPS to TSRM spec, and screwed the idle screw in all the way. This did not fix the issue. I tested the CSI time switch, was in spec. Tested the coolant temp sensor and it was in spec.

Would the low radiator fluid light send a code to the TCCS that would not let the car idle properly? He is low on fluid in his overflow tank.


I had him run the car, and I cut off all air to the throttle body (at the TB), and the car was still running, indicating an air leak somewhere in the system.


After all of that, the car still has issues, I cannot for the life of me figure it out

 

[jdub]

I had him over today, I was able to set the TPS to TSRM spec, and screwed the idle screw in all the way. This did not fix the issue. I tested the CSI time switch, was in spec. Tested the coolant temp sensor and it was in spec.

Would the low radiator fluid light send a code to the TCCS that would not let the car idle properly? He is low on fluid in his overflow tank.

I had him run the car, and I cut off all air to the throttle body (at the TB), and the car was still running, indicating an air leak somewhere in the system.

After all of that, the car still has issues, I cannot for the life of me figure it out

This is actually normal...at idle the TB plate should be fully closed, effectively doing the same thing. The ISCV is supplying air to the intake manifold

Do this instead: Block off air at the ISCV hose by pinching it shut. The motor dies, you do not have an air leak...if it runs, you do. An air leak in the system can cause all kind of mischief.

Did you check the accordion hose for any cracks/leaks?

How about the 3000 pipe to TB rubber connector?

Did you test the ISCV operation per the link I posted above?

Are there any codes remaining?


The reservoir warning light has no input.