I read the link that the West Coast Fiero dude posted but still didn't understand it. You are supposed to check the sensor with an ohm meter for resistance right? Theres 3 prongs on the sensor, so which 2? Is this with the car running or not? Unplug the wire connector and check or rig up some jumper wires? Then how do you adjust it to get it to the specs... which are what by the way? Thanks for any help

I'm still having trouble getting my TPS off of the motor. My GT will occasionally "forget" where idle is and fall on it's face when I lift my foot off of the accelerator. An ECU reset usually cures this however.

I'll replace the TPS when I get sick of doing this.

Sly

the fiero tps is not adjustable like tpi camaros or firebirds

Actually you can adjust the TPS on the V6 cars by bending the tab slightly. When I first got the 88 GT I adjusted the TPS using a volt-ohm meter and needle-nose pliers. At the time I had bought a new one; using the instructions I set the factory TPS so that the closed throttle resistance was within acceptable parameters. The factory TPS is still in use. Sorry, I don't remember the specific details.

You can test your TPS using a volt-ohm meter.

The TPS should gradually change in resistance as the wiper is swept from closed throttle to wide open throttle. If not, it is most likely toasted. Easily replaced.

Wells TPS124 $25.99 at Autozone. But, I'd probably order a AC Delco for longevity and reliability. If you are on a budget... AC Delco 10106063 $63.99 is a wee-bit expensive. Or, you may get lucky at a salvage yard, $5.00.

anyone else know the specifics? (v6 car by the way)

I stopped by Autozone after work tonight. Pulled a TPS from stock and to my suprise no installation instructions. I'll take a look in my Fiero book, may be lucky and have notes, but I doubt it.

Have you tested your TPS? Do the values steadily rise and fall? What are the min/max resistance values of your unit?

http://home.xnet.com/~nife/

click on "articles"

scroll down to "tps"

quote Originally posted by SLYGUY: I'm still having trouble getting my TPS off of the motor. My GT will occasionally "forget" where idle is and fall on it's face when I lift my foot off of the accelerator. An ECU reset usually cures this however. I'll replace the TPS when I get sick of doing this. Sly

root effect of a bad spot withing a potentiometer, when you come by again I will check it out for you. Sound just like a sticking or binding tps or, like mentioned a bad spot within the sensor

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Eric Nelson
Technician,
West Coast Fiero
www.cwestco.com
310-305-4111

I don't know if you have a volt-ohm meter (VOM). Since the car is in the garage, like 10 feet away, so I managed to find my cheap VOM and measured the TPS on my 88 GT. I assume the TPS is good.

From top to bottom the connections are A, B, and C. I checked it while on the car and move the TPS tab by hand.

Full range from AC is 4.33K ohm. AB min is 4.92K ohm, max is 1.01K ohm, and eyeballing middle is something like 3.3K ohm. By min, I mean closed throttle, by max I mean TPS tab rotated fully down.

BTW, be careful unplugging the TPS before you test it. The plastic tab on the side of the connector are bad about breaking; heat fatigue.

Also, when I find the box insert with adjustment instructions for the TPS, I'm going to the Sherrod libary and scan it and post it so you fellows don't think I'm a nut.

Hope this helps.

[This message has been edited by mindscape (edited 01-25-2002).]

Tech Article

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Eric Nelson
Technician,
West Coast Fiero
www.cwestco.com
310-305-4111

ok folks i stand somewhat corected..ive never seen a fiero tps with slotted mounting holes so if it did have them it would be adjustable..i used a snap on scan tool and at wot it said i only had 85%throttle..replaced tps with an ac delco piece and all was well..strangely enough it didnt have slotted mounting holes either..thanks for the tech article wcf

No stock TPS has sloted holes. You can drill them out yourself to get some adjustability. Still that will be good only to make it fit the parameters. ECM will learn whatever value the car has when engine fires up and start from there.

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Alex4mula
:) Red-Original Owner & Yellow AP-1/94 with PM (:

hehehe - spend your time trying to slot the holes with a file or drill motor hoping to gain the correct position as an end result - or just bend the tab, haha - your call

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Eric Nelson
Technician,
West Coast Fiero
310-305-4111

something keeps telling me if you have to adjust a non adjustable part it probably should be replaced..im pretty familure with efi and according to ed parks at the friero factory it shouldnt be adjustable..oh btw he happens to be a good buddy of mine..keith

OK heres what I did. I still dont know if i did it right though. I checked terminals B and C with a volt meter. with ohms for resistance. at closed throttle it was a little above 2 and wide open around 7. it did rise and fall smoothly. (non digital gauge. Im going to check it today with a digital one). With the sensor off the car the lowest was a little above 1. Isnt that where it should be? I bent the tab up as far as i could but it sill around 2. and it seemed to run worse. the car has been missing and maybe its an unrelated problem, but i still dont know if the TPS is right.

you want the idle voltage to be at .55mv plus or minmus .1 volt - no matter what though it must be under 1.00 volt at idle to function properly

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Eric Nelson
Technician,
West Coast Fiero
310-305-4111

OK i checked it with a digital meter today. turns out my $10 POS meter was off. You say check it at idle. so do I need to have the car running? Just unplug the wire connector and check the connectors on the sensor? I got around 1.18 at closed throttle and someting like 4.66 at wide open. (with the car off) I checked the sensor off my parts car and its pretty much the same. im tired of all this electircal BS

quote Originally posted by recluse: OK i checked it with a digital meter today. turns out my $10 POS meter was off. You say check it at idle. so do I need to have the car running? Just unplug the wire connector and check the connectors on the sensor? I got around 1.18 at closed throttle and someting like 4.66 at wide open. (with the car off) I checked the sensor off my parts car and its pretty much the same. im tired of all this electircal BS

nope - check it running w/ the car off. With the car of and just sitting there, you want the voltage to be at .55 mv.

------------------

Eric Nelson
Technician,
West Coast Fiero
310-305-4111

recluse - using your VOM - what are the resistance values? If you set the resistance values then it will be close, if not correct. When I set mine a few years back, I used the procedure where you have the key in the run position and measure voltage. To do this I used a couple of paper-clips. Slide the paper-clips into the connector from the back around the rubber water-seal.

Using your VOM tell me what the resistance is between terminals AB and AC; use the 20K ohm scale. Refer to my previous post.

Technically speaking, it should not matter whether or not you calibrate it using a voltage measurement or a resistance measurement. This is because the voltage supplied to the TPS is a constant, i.e., fixed value. It is the feed-back signale to the ECM that varies.

Eric, what resistance values do you get when measuring these TPS units?

I hope this makes sense...

quote Originally posted by West Coast Fiero: check it running w/ the car off.

with it running and the car off?? how can the car be running and off at the same time? why is this such a PITA? I guess since i cant understand any of this I will forget it and leave it all alone...

What Eric means, have the key in the run position. Don't start the car. Turn the key so that your insturments lightup and such. Just don't start.

Believe me, if you set the resistance it will be the SAME. And you can do this with the car OFF.

quote Originally posted by recluse: with it running and the car off?? how can the car be running and off at the same time? why is this such a PITA? I guess since i cant understand any of this I will forget it and leave it all alone...

haha - oh my gawd, too much caffeine - check it with the car off and not running - hehe, thats what I meant

------------------

Eric Nelson
Technician,
West Coast Fiero
310-305-4111

Im getting these codes:

21: high TPS voltage
22: low TPS voltage
24: speed sensor
35: There is no 35

the car stumbles when accelerating slowly or holding it at a high RPM, but when I open it up it accelerates smoothly, after stumbling for a second. This all happened after I put on a bored out TB and upper intake. I put on an adjustable fuel pressure regulator at the same time. I thought that was the problem so i put the stock one back on but it still does it. Feels like its not getting enough fuel. I had an old Z car that felt the same way when the fuel filter got clogged, it only did that under acceleration and the Fiero does it anytime but. I dont know what the problem is. Would the TPS cause this?

[This message has been edited by recluse (edited 01-27-2002).]

i ran into the same problems with a tpi camaro,as it turned out the previous owner had an adjustable preasure regulator on it with it set too high..lowered the fuel preasure and it took away the stumble.a lazy tps would give the stumble as well..keith

>recluse
>Im getting these codes:

>21: high TPS voltage
>22: low TPS voltage
>24: speed sensor
>35: There is no 35

What do you mean there is no code 35? A code 35 is Idle Air Control - set when at closed throttle idle speed is 50 rpm above/below correct idle speed for 30 seconds.

I could probably help you better if I knew the resistance values of the TPS closed and at full throttle. I'm also suspicious that you could have a wiring problem; unsure.

If I wasn't so BUSY with thesis research and fixing my 88GT I'd offer to drive over one weekend and give you a hand. Hickory NC isn't that far from Bristol TN, is it; about an hour?

Tell me, am I invisible or what?

[This message has been edited by mindscape (edited 01-27-2002).]

quote Originally posted by mindscape: >recluse >Im getting these codes: >21: high TPS voltage >22: low TPS voltage >24: speed sensor >35: There is no 35 What do you mean there is no code 35? A code 35 is Idle Air Control - set when at closed throttle idle speed is 50 rpm above/below correct idle speed for 30 seconds. I could probably help you better if I knew the resistance values of the TPS closed and at full throttle. I'm also suspicious that you could have a wiring problem; unsure. If I wasn't so BUSY with thesis research and fixing my 88GT I'd offer to drive over one weekend and give you a hand. Hickory NC isn't that far from Bristol TN, is it; about an hour? Tell me, am I invisible or what? [This message has been edited by mindscape (edited 01-27-2002).]

Ok first theres no code 35 listed in my Chiltons book. SO I guess the chiltons books suck as bad as the haynes. This is what I posted yesterday about the readings I got, (a few posts up)

"OK i checked it with a digital meter today. turns out my $10 POS meter was off. You say check it at idle. so do I need to have the car running? Just unplug the wire connector and check the connectors on the sensor? I got around 1.18 at closed throttle and someting like 4.66 at wide open. (with the car off) I checked the sensor off my parts car and its pretty much the same. im tired of all this electircal BS"

I checked the resistance. (ohms) I still dont know if THAT is even right, no one would make this clear. I checked terminals B and C, which is what Eric (WCF) suggested in an above post.

Ive tried 2 different TPS's on the car and it does the same thing. Like i said before it just started doing this after I put on the bored out TB and intake and played around with the fuel pressure reg. I dont really think it has much to do with the TPS but i was just trying to see if I had it right to eliminate that as a possibility. Could it just be getting too much air now, so much that the computer cant give enough fuel? Im tempted to put the old TB and intake back on and see what happens. I dont know about Bristol TN. Thanks for the thought but I would hate for you to drive all that way. Im sure I'll figure it out soon.

[This message has been edited by recluse (edited 01-27-2002).]

[This message has been edited by recluse (edited 01-27-2002).]

Scrolling back I see the message posted more than once.

[This message has been edited by mindscape (edited 01-28-2002).]

I think you are about 70 miles away. When I get the 88GT done, I would come over and help.

Humor me, make a table of values, TPS wiring harness disconnected, engine off and keys out of the ignition. Readings should be like the following, listed closed throttle, fully open throttle.

AB 4.92 1.01
BC 1.60 5.32
AC 4.33 (does not change)

All values are in K-ohms, and should be reasonably close.

Next, with the TPS connector unplugged and the ignition key in the run position (engine not running) read the voltage across A and B on the wiring harness. Red VOM lead to terminal A and black VOM lead to terminal C. What is the voltage?

BTW, I have to ask. Is the TPS plugged in backwards? Make sure terminal A is on top. Top to bottom the wires should be Grey (A), Blue (B), and Black (C). I'm just trying to think of a scenario where both codes 21 and code 22 can be set simultaneously.

You may want to take a read at the following: http://www.syty.org/old/d&e.html

[This message has been edited by mindscape (edited 01-28-2002).]

I have not checked the TPS voltage yet again because I have to go to my friends house to borrow his digital meter. But I did however unplug my battery today to make sure I had any old codes cleared from my computer and low and behold Im not getting any codes now. I guess I never cleared them last time.

quote Originally posted by West Coast Fiero: you want the idle voltage to be at .55mv plus or minmus .1 volt - no matter what though it must be under 1.00 volt at idle to function properly

Eric, .55mV is .00055 Volts. Do you not mean 550mV or .55 Volts. That is the table in your article show volts not milli-volts.

Think about it, .00055 volts plus or minus .1 volts?

Just thought I'd clearup any confusion for anyone reading this in the future.

quote Originally posted by mindscape: Eric, .55mV is .00055 Volts. Do you not mean 550mV or .55 Volts. That is the table in your article show volts not milli-volts. Think about it, .00055 volts plus or minus .1 volts? Just thought I'd clearup any confusion for anyone reading this in the future.

you are absolutely right- .55V

hehe - I need to pay attention to my own articles

Found the problem! EGR valve. Unplugged it the vac line and it ran great. Now to find a good replacement...