TPS problem

[Ilikebigbutts]

Ok, i'm having a tps problem, but not your typical tps problem.The problem lies in the wiring, not the sensor its self.First off,the yellow wire is getting 5 volts, and the green wire is grounding.The red/black wire on the other hand, is only getting some mv (millivolts).I looks at the book, and traced the red wire to the bigass connector right on top of the injector resistor, i'm pretty sure you guys know what i'm talking about.I probed pin # 13 (i hope thats it), and i'm getting about the same reading (mv).So there is and open some where in the harness under the dash, which i have no intention of going at.My question to you is...What would you do in my situation...or better yet, what HAVE you done(if you've ever been in my situation).My first thought was splicing the wire right before the connector that connects to the sensor, and then running it through the fire wall and splicing it through the wire right before it connects to the ecu...

any suggestions are welcomed.

ILBB

EDIT:BTW, it doenst even hold idle, it throws a cel and shuts off with in two seconds of start up.

[Ilikebigbutts]

bump!

[Ilikebigbutts]

no suggestions???

o well

ILBB

[CB3]

You mentioned that you got this CEL fixed. I am having similar problems and I was wondering what your solution was? Any insight?

[Ilikebigbutts]

i just adjusted it with my DMM.I thought it wasnt adjusted before but after being patient enough i got adjusted to .45 volts.No CEL or anything.

ILBB

[timmy0tool]

why not check the wiring that go directly into the ECU? how is the voltage there? maybe a pin came loose and is not in contact . good luck ILBB!

[92accordexpower]

sorry i don't feel like looking up the wiring diag right now, so I could be mistaken, but...
Usually, the TPS only gets a reference of 5volts. That means one wire should be 5 volts, one wire should be ground, and one wire is gonna be dependant on where your throttle plate is, between about .5 -> and 5 volts. If you're sensor is bad, you will be seeing a bad voltage on the sensor wire, also make sure you have a good ground at the connector.

Best bet is to get a labscope, and do the following....
Get a normal labscope with 2 test leads. Put one test lead to a good ground, battery would work. Put the other test lead to the output wire of your TPS. Not your positive wire, not your ground, the third one, get a wiring diagram to figure out which one. it should look like a record needle on the wiring diagram.
Then, once you get that hooked up, turn the ignition to on (all the way, but not running (KOEO).
Adjust your scope to show 1-2 seconds, and 5 volts. Then, in about 1-2 seconds, open your throttle plate and close it by hand, smoothly. you should see an ant hill basically... here's an example all though it's a crappy one, just something i pulled off google....


If you get something like this next one, then your tps is bad....


and if you don't get the anthill, then you either have bad wiring, or your scope is set up wrong.


i'm not familiar with the cb7 TPS specifically, but with my eg6 civic, TPS has very little impact @ idle, and it will run just fine without it. When it has impact is when you are getting air into the intake (vacuum leak), and the TPS reads closed throttle. you may have other problems complicating the TPS situation, maybe something that doesn't throw a code.

let's remember, after all, TPS does not determine fuel pulse width, thats mostly dependant on MAP, TPS will just add or decrease the number of pulses made, and it only makes a difference under change for the most part, i.e. acceleration/decel, not idle.

try giving it a vacuum leak and starting it up, see if it idles, as crappy as it may be.

feel free to PM/email me with questions

-Dan

[92accordexpower]

Ok, here's the wiring diagram, you need to check for the "anthill" on the Red/black wire, 1 lead there, the other on ground.

Note the wiring Diagram: There is NO wire that goes to the injector resistor, from the TPS, i don't know where you got that from. It shares a ground with the 02 sensor, IAC, and alot of other sensors etc.

to recap, 5v at the yel/wht wire, ground @ grn/wht, and variable based on thottle position at red/black, KOEO, or KOER.
questions?

[CB3]

Sorry to jack this thread, but I was having similar issues.
Thank-you for your help. Excellant work.