Piranha

Well, after the voltage trick, my needle jumping has ceased, I don't get black smoke at idle, and it seems a little peppier 3-2K RPMs... but when I got past about 2/3rds throttle, I get massive backfiring. I let off once and saw a HUGE puff of black smoke. While it looked cool... it didn't work.

I don't see how the voltage and the light tests differ. Wouldn't moving the TPS change the output (hence voltage)?

Sniper_X

there should be a certain voltage at the close throttle point.

The ECU wants to see idle at a particular voltage.

Then the lights tell you when you have the Throttle body mechanism at the right point at idle and then the transition to WOT according to the ECU is proper and timed right.

its all based on a known point in space for the TPS at idle.

Usually the voltage is right becuase there is no real movement available at the mount point for the TPS.

Once its attached, its in the right place 99.9% of the time.

Check out the factory service guide online at FC3S.ORG.

the procedures are there and well documented.

Works for me every time if the TPS is good and has no open spots.

HAILERS

Know what the two bug lights represent??? When they are lit??? They represent a ground being put on the Switching solenoid and the Relief solenoid.

When the output(green/red wire) From the tps TO the ECU is approx one volt, the ECU then puts a ground signal on the Relief solenoid(Blue) and takes the ground signal off the Switching solenoid(Grey). That represents one light on and one light off if you use the check connector and the two bug lights.

See your schematic that shows the solenoids and you see a wire splice coming off the wires from the ECU going to the Switching and Relief solenoids. Those two wire splices go to the check connector(The check connector being the green, three socket one). The two lower sockets in the check connector to be specific. The lone upper socket/spade has 12v on it all the time to power up the bug lights when the ECU puts a ground signal on the switching and relief solenoids, and hence the two lower sockets/spades on the check connector.

With a fully warmed up engine, the tps set right, you should see one volt at idle and when the throttle is full open approx 4.5 volts. There is a little fudge on either side of those values where nothing bad happens. In fact expect the value to change a smidge each time you check it. Mechanical things have a touch of play in them.

Once again, the ohms method might be the way to go if you suspect a corrupt tps. You can look for opens in the wiper/pot as you run it thru its full range.

Just wasting time until the end of the work day.

Piranha

heh, its not a waste of time to me. The Air Force teaches mechanics theory of operation so that we can diagnose problems. Also... I can't find that 3 prong connector. I've searched all over by the boost sensor. I know this is a 2nd engine and Jspec, and I didn't install it myself. :-/

HAILERS

On a TurboII its located on the left side of the engine. Around the oil filler cap area. On the N/A its on the r/h side of the engine bay, close to the pressure/boost sensor. Green in color. Three socket/prong. jpg attached.

Piranha

thank you very much HAILERS!

Piranha

Hey guys, just for a followup... well, I had started trying to adjust my TPS with the resistance method, and that never worked for me. I tried the voltage, but that didn't do it either. After I understood how the light test worked, I did that, and it fixed my problem. I'm still getting a little bucking, but I'm ordering a new fuel pump right now (as well as an A/F meter). Thanks for the help.