Operation/settings on 92 240SX TPS

[alexh]

Hi,

I have a 92 240SX auto which has a lot of odd behavior all of it intermittent including - hesistation on acceleration from dead stop, occasionally runs extremely rich, cut out on accel once or twice, and has failed to start a few times.

I have really beat myself up on this one for almost a year now and I keep coming back to the TPS. First of all, the manual does not give resistance measurements like most cars - it gives voltages which requires that I use a pin to stick the wire (or apply a 5V source which is a pain) which I hate to do. What's also odd is that the graph they show has 0V when the throttle is closed. The manual also says that the auto does not use the hard closed switch. I have replaced TPS switches on cars before and there is usually very detailed info on how to set them.

Anyhow, I performed a few tests on the TPS.

First of all, I tried disconnecting the TPS to see how the engine behaved. The idle wandered a little or it drifted down to about 550 rpm. This is very similar to the idle behavior I see when the car is in a weird mode.

Also, I noticed that if I blip the throttle in neutral, there is a pronounced hesistation which makes sense and this is also behavior that I see - very common to have slight hesistation and sometimes it's like there's no throttle for a second or 2.

Finally, I measured the resistance with the plug disconnected -

Between pins 5 and 6 (I might have the pin #'s wrong) I get -

Throttle closed - 9k Ohms, Throttle WOT - 2k Ohms

Between pins 4 and 5 I get -

Throttle closed - 1.02k Ohms, Throttle WOT 8k Ohms

Anyone have any data to confirm this or should I use the 5V method and if so, how?

Thanks

[alexh]

Ok, I found this resistance info. Not sure if it applies but I'm betting it does.

http://www.nissansilvia.com/fo...51047