TPS adjustments, unclear on voltage readings.

Nathaninwa · 06-18-2011, 03:06 AM

Long story short....new registered member, but not at all new to the Supra/7m series engine scene. There is so much info that searching can usually find what I need. About 3 years ago I installed a 7m into my trail truck with a Cressida harness and ECU. Got it running and more or less drove it, but has always felt like its been down on power. So recently I have installed an 87 MT supra ECU, made an adapter harness from the old style plug to the newer style grey plug by sacraficing a spare ecu I had. Now I am going through and verifying all the info i can. Ive come down to the TPS....NSW/AC....and the speed signal

My questions.....does the ECU need to have a NSW signal and an A/C signal, or will this just pop a code 51?

Does the ECU use the speed sensor signal for any fueling/timing adjustments?

And I have adjusted the TPS according the to the online TSRM ( http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=101 ), and all is within ohm spec at all points. But when it comes to checking voltages I have a problem. My information comes from ALLDATA. 87 supra 7mge should read 4-5 volts at wot on VTA, and I get 3.6 volts, no matter what tps number I am using. And I am supposed to get 10-14 on the IDL pin at WOT and I get zero.
In reference, the 1990 Cressida ecu wants 3.2-4.2 at the VTA, and 4-6 volts on the IDL pin.

I can adjust the tps to read 4.1 volts at WOT before the voltage drops out to zero, but then idle is way off....and neither option gives me 10-14 volts on the IDL pin.

I have not tested the Cressida ECU, only the Supra as I am wantring to get away from the auto ecu setup, and possible power downage from improper inputs on the tranny side, and possible no VSS signal.

Im working some other kinks on the truck before I can drive it, just wanting to solve the voltage questions on the ECU before I button it all up.

06-18-2011, 03:06 AM	#1
Nathaninwa Intake Join Date: Jun 2011 Location: Aberdeen, WA Posts: 43	TPS adjustments, unclear on voltage readings. Long story short....new registered member, but not at all new to the Supra/7m series engine scene. There is so much info that searching can usually find what I need. About 3 years ago I installed a 7m into my trail truck with a Cressida harness and ECU. Got it running and more or less drove it, but has always felt like its been down on power. So recently I have installed an 87 MT supra ECU, made an adapter harness from the old style plug to the newer style grey plug by sacraficing a spare ecu I had. Now I am going through and verifying all the info i can. Ive come down to the TPS....NSW/AC....and the speed signal My questions.....does the ECU need to have a NSW signal and an A/C signal, or will this just pop a code 51? Does the ECU use the speed sensor signal for any fueling/timing adjustments? And I have adjusted the TPS according the to the online TSRM ( http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=101 ), and all is within ohm spec at all points. But when it comes to checking voltages I have a problem. My information comes from ALLDATA. 87 supra 7mge should read 4-5 volts at wot on VTA, and I get 3.6 volts, no matter what tps number I am using. And I am supposed to get 10-14 on the IDL pin at WOT and I get zero. In reference, the 1990 Cressida ecu wants 3.2-4.2 at the VTA, and 4-6 volts on the IDL pin. I can adjust the tps to read 4.1 volts at WOT before the voltage drops out to zero, but then idle is way off....and neither option gives me 10-14 volts on the IDL pin. I have not tested the Cressida ECU, only the Supra as I am wantring to get away from the auto ecu setup, and possible power downage from improper inputs on the tranny side, and possible no VSS signal. Im working some other kinks on the truck before I can drive it, just wanting to solve the voltage questions on the ECU before I button it all up.