TPS

[1975 280zbackyardfind]

My TPS ,my 75 280z will run better when the tps is unplugged, does this mean that i need to purchase a new one.Will not rev pass 2500 when plugged up.

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[BRAAP]

Due to the fact that when the TPS is plugged in the engine wont rev past 2500 RPM, (probably like a violent rev-limiter kicking in at exactly 3200 RPM, engine comes back online at exactly 2800 RPM), and is fine unplugged, that indicates the idle switch is closed.

 

1) Unplug the TPS and look for water in the connecter on the TPS itself. If there is water in that connector, just blow it out, get it dry, plug your TPS back in and you should be fine. Water in the TPS connector is the most common cause for this, typically after washing the engine or some how water is able to get on the TPS.

 

2) If not water, using a continuity checker, verify the TPS is functioning. It is merely a double throw switch. Center pin is common. One of the outer pins makes connection to the common pin with the TPS closed, (indicating to the ECU idle which the ECU also uses to cut fuel above 3200 RPM, brings it back in at 2800 RPM as mention above), then opens as soon as the throttle is cracked open, (your Haynes manual or shop manual shows how to set that), the other pin makes connection with the middle common pin at approx 3/4 travel and maintains connection through to WOT.

 

Hope that helps and remember when troubleshooting to look through your shop manual/Haynes manual.

 

And please be sure to read the forum rules linked in the upper right hand corner of the page. Descriptive thread titles is one of those rules.

[galloguy05]

I agree with BRAAP. In fact, I believe he was the one that helped me solve my tps issue when I first got my Z. Mine did the same exact thing and it turned out there was a little water in the bottom of the sensor housing. I stuck some paper towel in there to get any visable water, and then just let it air dry for a few days and then plugged it back in and i have not had a single issue with it since then.

 

I also had a little bit of rust on one of the pins that wasnt allowing it to connect right (because of the water it rusted) so i took a bit of sand paper to it as well just to be sure. Hope it all works out for you.