Hi all: Have a 90 GTU non-turbo-manual trans. Getting check engine light on decelleration/idle. Local import shop says TPS all over the place and burning out the O2 sensor. But car performs just fine-except some minor pops/misses during warm-up. Just changed plugs/wires-idling fine. Questions: Can a bad O2 sensor cause the check light to come on? Is the TPS only out of adjustment and they are trrying to sell me one? If I need a new TPS where can I find detailed directions for adjustment proceedure? Any advice is appreciated-

Professor Steve-Southern Illinois

 

Go to this site http://home.rmci.net/panther/ecu_codes.htm and download the codes yourself, and let us know what happened. Were the codes the same as the shop said?

 

Thanks-I've already got this inforamtion and will be checking codes soon. Also searched back through some older posts-I got a great deal of specific info on these areas-This forum is very very good-I'll post the results of my own code search soon-Many thanks!- Prof. Steve

 

Also go to http://www.fc3s.org and download the Fuel section(of the 89 manual). In specific, page F2-81 but reading the first part of that chapter won't hurt.

 

That makes no sense, as these two sensors have nothing to do with each other. Let us know what codes you get and we'll try to help you out.

 

Okay-Checked codes-good news is my shop is honest-I got a Code 12-TPS full range-and code 17-Feedback system for O2 sensor. Strange thing is my car is running
great-no hesiatation-solid idle-strong power thru entire throttle range-Can the TPS act up intermittently? But I'll defer to the expertise here on the forum as to next steps-Thanks!

 

If the 02 sensors wire is connected, then you might just go buy a 20-30 dollar Robert Bosch 02 sensor from the auto store, and replace it.

The full range tps signal......go to the manual and ohm it out. Page F2-81.

If you reset the ECU, by disconnecting the battery for the designated time(I don't have a series five, so I don't remember the time, five minutes?), and then reconnect the battery and start the car, do you still have the codes popping up?? Probably, the shop should have done this when they checked the car.

 

Just remeber when you reset the ecu, you'll need to get the car up to temp, and drive on the highway to see if there is an error in the O2 circuit. Don't know about the tps. If O2 code appears, you'll need to see if signal is being sent to ecu. Could be a broken wire, but as stated above, buy new O2 sensor then check.

 

Thanks to both for the advice-I'll disconnect batt. and see if codes clear and/or reappear-(I dont think shop did this-neg. terminal still dusty) 5 seconds the time?-based on info from rmci.net/panther/89_91ecu. code proceedures. I'll try and ohm out the tps too-is this with or without the ignition in the 'on' position?-I'll take this one step at a time-O2 sensor sounds hard to replace-I'll get the Bosch and an O2 socket-Forum posts say to soak threads with liquid wrench overnight-remove when engine is hot-Does this sound correct?
By the way the O2 wires are in place-Thanks again and I'll report findings-you guys are great!
Prof. Steve-SIUC

 

Yeah, if you had no problem when your car is warming up, but you get the light after driving around, that could be a "hole" in the TPS. basically the resistance jumps around, and the ECU doesn't see what it should see, confusing (if you can confuse these simple computers, ha ha haaaa) giving you a code.

 

Ohm it out with the tps connector disconnected. Move the throttle from full closed to full open with your fingers.

Just a note. I have a 87(no engine warning light). I have two bug lights from the cabin to the download connector. I've seen the o2 code on a long trip while crusing. Gunned the engine for a minute and it disappeared. Did this several times. Replace 02 sensor. Does that no more(code). So I'm saying the O2 may fail intermittently if old.

 

Quick follow-up questions: To erase ecu memory should I remove neg. batt. connector with the igintion on or off? Same question for the tps ohm test-ignition on or the off ?- Thanks! Prof. Steve SIUC

 

I had the Feedback error on my car. It was annoying. What ended up happening was that the wire for the sensor had broken in the harness and was touching something else broken.

It was resulting in a short. My solution was this. I ran a new wire from the o2 sensor and drilled a small hole in the firewall where the drain is for the AC condensor. I then ran this wire into the passenger floor board by the ECU. I found the wire that was the input for the 02 sensor and cut it. Then soldered my new wire into that. Problem solved.

Also, to erase the memory disconect the negative and that is it. Sorry, but not sure on the second question.

James

 

Okay-Replaced O2 sensor-cleared code 17! Still getting code 12-Just checked ohms-Narrow range 1.22 closed-6.0 open (barely within max spec) Full range 5.1 full-Closed at .2 well below lower range .6-Is this 'adjustable' or should I pop for a new one?(121K on car)- If a new one-any suggestions for best source/price? Thanks again all-you've helped a great deal! Prof. Steve

 

TPS you can find here for $325 (-WOW-).

http://www.mazdatrix.com/c-6.htm

I would make damn sure that sum bitch is busted before you go and spend that much cash. You might even be able to find some nice forum member who has a spare one laying around for a small fee.

If you are giving up on your old TPS; I would suggest trying my last ditch effort to salvage it. I took a can of electrical contact cleaner and sprayed the hell out of my TPS. I sprayed the wire connectors and tried to get as much as I could to get past the plunger and inside the unit. I then let it sit for the weekend to dry out and hooked it back up. Wouldn't ya know it worked! Maybe mine was just a rare example of one that got a little dirty inside but like I said, if you've already given up on it then it's worth a shot right! I don't however recommend this to anyone with a properly working TPS sensor.

 

Really shouldn't try to answer this because I have only series four tps which is different.

It does not seem that far out to me. You might try to slowly put it thru its travel and look for spots that show the pot being open intermittently. Now that would be a sign of a real bad tps(open in the travel b/t close and open).

I've read somewhere where a guy with a series five recommended doing a little bending of the tps bracket to get it to fall into range. If I find that, I'll post it. Again, I shouldn't be talking about series five tps.

But... look on page F2=78 of the Fuel section. Look for the narrow and full range of the tps, then look out to the right of each and see what the voltage should be at idle. See the .8v, 4.3v and .8v???? Do what the page suggests. Put the key to on. Measure the output of the full range sensor. Then move the throttle to wide open and read the voltage, and last check the voltage at idle. How close are your cars to the figures on the page???

You can do that by putting the tps plug back together, and inserting the volt meter pos lead up the backside of the plug. You'll need to make sure your on the right wire though. That would be *E* as is shown on page F2-81.

You might want to read this: http://www.johnr.com/tps.html I'm not resposible for anything.

Lets see.....a little bracket bending vs three hundred bucks.....Last resort.

 

Hint - Spray contact cleaner. I got mine from Home Depot. Like Samps, I sprayed in in the TPS plungers, worked it in, and blew it out. The VOM readings went from erratic to smoooth.
That stuff is also great on the pots behind the radio *****, the logicon slides, the inside driver's door lock contacts, MAF contacts Etc..

 

Spray sounds like the first thing to do. No argument from me on that.