tps

Topic: tps (Read 2004 times) previous topic - next topic

Reply #15 – September 04, 2009, 12:08:28 AM

a few shots of what your asking about . notice the tps takes up one eec postion on the stock layout while it takes up three eec positions on the stang layout.
The green wire is the variable resistor center tap. it will read less than a volt in the rest postion and max nearly 4.5 to 5v wide open.

kitz- .jpg is your friend, not GIF
right click , save as bmp or jpg. convert everything to jpg in the end.

tps

Reply #16 – September 04, 2009, 12:29:16 AM

if you have 5v on the TP, likely there is an open between the green wire on the tps up to the eec connector.

Tone from the eec pin 47 up the the tps connector green wire.

the readings you got are assuming the tps was plugged in while you were reading.

other unlikely option is (since you tried a couple others),
the tps green (wiper) is stuck at max although the mechanical do hicky still rotates like normal
your test tps is wired bass akwards physically and you just havent noticed it yet (ie= the orientation of the wiring is flipped blk to green)
examine the connector key way and insure the tps you used isnt wire different with respect to what color wire passes through the engine harness up to the tps. (ie- make sure green comes in and ends up at the green wire on the physical green on the tps.)

i think i have a tps in the garage that when i plug it in, the engine harness black lands on the tps org. not sure where it came from.

tps

Reply #17 – September 04, 2009, 01:28:16 PM

after messing with it a while i found out a couple more things. the green wire has .5 volt on it cause the ground wire actually does too and its like backfeeding through the green. so somehow the ground is messed up but its in the correct spot from what you all have said. but i was thinking, can i just run the ground as a regular old ground? does it really need to ground through the computer? i'm kinda running out of options since its in the correct computer slot. and i really down mind just regular grounding it if it will work

tps

Reply #18 – September 04, 2009, 11:39:38 PM

Quote from: grutinator;289876

after messing with it a while i found out a couple more things. the green wire has .5 volt on it cause the ground wire actually does too and its like backfeeding through the green. so somehow the ground is messed up but its in the correct spot from what you all have said. but i was thinking, can i just run the ground as a regular old ground? does it really need to ground through the computer? i'm kinda running out of options since its in the correct computer slot. and i really down mind just regular grounding it if it will work

There IS a reason that ground goes back to the computer. It's an isolated common, not GROUND. There are filters in the EEC to prevent RF interference on the TPS circuit. If you ground that, it's very possible to damage the 5V source power supply in the EEC, not to mention you'll have no end of gremlins with idle, fuel economy, and driveability. Find the break in the wire and fix it. Don't ground that wire.

tps

Reply #19 – September 05, 2009, 10:07:48 AM

you would need someone to compare few things.

measure from the green to black KOEO

masure from the orange to green KOEO

measure from the black to engine intake KOEO

Measure from the green to intake KOEO

measure from the Orange to intake KOEO

measure orange to black KOEO

sounds to me you have an open on the ground to but ive never looked at this black wire that close before so im not sure what should be on it with KOEO. I would assume you should see zero volts with KOEO but maybe its only zero with KOER.

I dont sugggest running the black directly to common ground either.

tps

Reply #20 – September 05, 2009, 12:30:35 PM

You may have an issue with that computer, And it might be affecting the other sensors also. unplug the maf and try your old comp and see what you get on the tps, just to test the circuit.

tps

Reply #21 – September 05, 2009, 01:15:25 PM

Quote from: Kitz Kat;289996

You may have an issue with that computer, And it might be affecting the other sensors also. unplug the maf and try your old comp and see what you get on the tps, just to test the circuit.

thats a good idea. yeah i was thinking the computer could be bad too. so maybe ill try that. i wish a had another maf computer around that make things alot easier

tps

Reply #22 – September 05, 2009, 08:38:44 PM

You should have 0 V, or darn near it on the black Signal Common wire. The orange wire (VREF) should have 5V (+/- 5%) on it any time the key is on. The green wire (TP) should range from roughly 0.9 to 4.9 as the throttle is opened. Move the throttle slowly, and watch for any sudden change that is NOT something you're doing with the throttle. It's a whole lot easier to see if you use an buttstuffog meter to check it, such as a Simpson 260. DVM's just aren't fast enough.

SIG RTN should NOT be grounded, despite the deceptive 0V reading. The primary purpose of that wire is for noise cancellation on any signal coming from any sensor which may pick up some RF noise. If it's on the signal, it will be on the return, and will cancel.

The EEC is a digital device, and digital devices DO NOT like noise. Chances are, if you ground that, you will cause the 5V supply (VREF) to fail.

tps

Reply #23 – September 05, 2009, 09:02:38 PM

well the more i find out the more confusing it gets. i pulled the ground wire out of the computer and the computer itself puts out almost no voltage for that slot(KOEO). but with the wire still disconected, testing the wire shows 5v. so it cant be the computer. i pulled all the other sensors on that wire one by one to see if the 5v went away but it didnt. i pulled the tps, map, coolant sensor, and the egr. i didnt see any obvious frayed wires or anything crazy. still the 5v. lame

tps

Reply #24 – September 05, 2009, 11:12:27 PM

With signal return disconnected at the ECU, you'd have to disconnect all the other sensors on the signal return to eliminate the voltage that is being fed through those... IF you have 5v on the signal return when connected to the ECU, then that circuit is likely open inside the puter... Swap the SD one back in and retest...

tps

Reply #25 – September 06, 2009, 01:46:46 AM

if he has the same voltage at the self test conn, then yea its the eec.

if not, likely an open at conn C477 or the following splice point.

check continuity from the eec self test conn up to the tps black wire.

tps

Reply #26 – September 06, 2009, 01:30:16 PM

yep. it must be the eec. plugged in my original tbird computer. everything went back to the way it should. so ill see what i can find in the way of a new one. thanks a ton guys

tps

Reply #27 – September 06, 2009, 03:28:16 PM

Try grounding the signal return line... May not run as it should but won't hurt anything at this point...

tps

Reply #28 – September 06, 2009, 04:08:49 PM

haha, well i thought that wouldn't be too good. i'll just wait and look for a good computer. this kinda sucks but i guess thats what happens when you're dealing with old used parts.

tps

Reply #29 – September 07, 2009, 01:45:11 AM

I ran a 3.8 tan/light green wire grounded to chassis where it normally would get a ground from the eec to remedy the fuel pump not coming on.

end result was the pump ran for 3-4 sec after i shut off the car. pretty much the time it takes the eec relay to cut off.

It will work for now,,, now that you know the eec is fubar.