MIBPreacher Posted May 6, 2006 Share Posted May 6, 2006 I have noticed on random occasions that my 300zx will start bogging down by itself and I have to keep 1 foot on the brake and 1 on the gas to keep it idleing. I noticed that when I wiggled the TVS connector, the car would idle again, but the connector is so loose. any ways, I have my 5spd in the shed and it came with the Throttle Valve Switch for a manual, so I put that one on and my Z idles really nice now, but I have to wonder what that pigtail connects to off of the automatic version one. Do you think I will be ok driving without it connected? Does anyone know where that connector leads? Quote Link to comment Share on other sites More sharing options...
Guest ZFury Posted May 14, 2006 Share Posted May 14, 2006 The second connector is for the automatic as you have said. It is a for the poto (poto is short for something I cant spell) TPS sensor part. The manual TPS is like an on/off switch, while the automotics poto sensor gives the exact position of the throttle. Like if your at 10%, 25% or 90% throttle. You can put a automatics tps on a manual car, but the second plug should do nothing. I leave mine unpluged just it case it does do sumtin'. Quote Link to comment Share on other sites More sharing options...
Hugh Posted May 14, 2006 Share Posted May 14, 2006 On an automatic TPS, the pigtail is typically the kickdown for the auto tranny. The kickdown is an on/off switch. It tells the transmission to shift down a gear when you go near full throttle. (for passing or quick acceleration) TPS is used by just about every EFI engine, regardless of transmission type, and is a potentiometer (or reostat) which varies in resistance according to throttle position. The ECU knows how to compensate for throttle changes by how the TPS signal changes. (ie: you punch the gas, and the computer knows to dump a little extra fuel to compensate for the surge of air thats coming) The manual TPS should work as a potentiometer, not a switch. Quote Link to comment Share on other sites More sharing options...
Guest ZFury Posted May 14, 2006 Share Posted May 14, 2006 The manual TPS should work as a potentiometer' date=' not a switch.[/quote'] I was told different. Because when you want to use an after market ECU or piggy-back ECU you have to get a TPS from an automatic and use the extra connector for the TPS connection for the after market ECU. I could have it mixed up though... But you can have the car running and twist the TPS and it wont do anything on a manual. Quote Link to comment Share on other sites More sharing options...
Hugh Posted May 14, 2006 Share Posted May 14, 2006 Ahh, maybe its different on your Z. I don't know much about the 80's cars. (70's&90's a lot moreso) Quote Link to comment Share on other sites More sharing options...
MIBPreacher Posted May 15, 2006 Author Share Posted May 15, 2006 If you unplug that second pigtail from the TPS, the OD no longer works on your car. That is what I found out when I plugged my donor TPS from a manual in my car. The OD switch has no power nor did it light when depressing the button. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted May 20, 2006 Share Posted May 20, 2006 Zfury is correct. The Nissan ECCS uses a idle switch for the EFI and a pot for the transmission control. The connector on the pigtail is for the pot. You can use it for standalone TPS information. Some of the units also have a full throttle switch, but I don't think that the 300zx uses this input. The ECCS uses mass airflow and rpm, among other inputs, to calculate load instead of TPS, same as the Jetronic on the early cars. Doug Quote Link to comment Share on other sites More sharing options...
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