What Is This? What Does It Do?

[hijaked]

Hi everyone

while looking at my engine, i noticed that theres a little black box attached to the thottle body... yet there were no wires goign to it. what is it and is it bad if its not talking to my car??

heres a pic:

[d00dz]

Thats some dianostic plug.

Dont worry about it. Mine doesnt have it and alot of cars dont have it plugged int too.

[Tommyk]

i do believe thats a plug for the automatic transmission

your car is probably manaul

[SteveL]

while looking at my engine, i noticed that theres a little black box attached to the thottle body... yet there were no wires goign to it. what is it and is it bad if its not talking to my car??

<{POST_SNAPBACK}>

It's the TPS (=throttle position sensor). If you look closely you'll see a short lead coming out 'underneath' that grey connector which leads to another connector just near by - I think it's the one you can see just below the TPS. It's connected to the ECU and tells the engine management whether your at idle or not. That is used for either auto or manual cars. The grey connector which has no wires (on a manual - auto cars would have wires) is only used on auto's and tells the auto management system the exact throttle position via a voltage divider cct. If your car is a manual, don't worry about it.

[hijaked]

oh thanks guys.

its just my mates R33 Manual has it with wires.. and my car is running like garbage at the moment... i thought maybe that had sumthing to do with it

[blind_elk]

It's the TPS (=throttle position sensor).  If you look closely you'll see a short lead coming out 'underneath' that grey connector which leads to another connector just near by - I think it's the one you can see just below the TPS.    It's connected to the ECU and tells the engine management whether your at idle or not.  That is used for either auto or manual cars.  The grey connector which has no wires (on a manual - auto cars would have wires) is only used on auto's and tells the auto management system the exact throttle position via a voltage divider cct.  If your car is a manual, don't worry about it.

<{POST_SNAPBACK}>

My manual R32 has (actually had - don't have a RB20 any more) wires coming out of that plug (and the bottom one as well).

I believe that the one we can see is the TP Switch, which tells the ECU if the throttle is closed or WOT and is sometimes the cause of the high idle often reported on these forums. The one on the underside is the TP Sensor, which tells the ECU the actual throttle position.