As I look at the Chilton instructions,then I look at the throttle body of the V6, it appears that the TPS just unscrews with the two torx screws holding it in place. Am I looking in the right place, that is, opposite the throttle cable, opposite the firewall manifold? It looks pretty easy to replace, unless I'm either looking at the wrong part or overly optimistic.
The instructions I received with the TPS indicate that I have to remove the throttle body, etc., etc. Is all this necessary, or can I just do as I read here, and remove and replace the TPS by itself? Thanks, bb
Just remove the connector and the 2 screws, swap out the sensor and reinstall the screws with the metal bridge hold down and plug it back in. I've changed out a couple and never adjusted them. Actually, I didn't know you could adjust them. I have 3 of them before me and there are no adjustment screws of any kind. Pray tell, how do you adjust it?
the holes are slightly slotted, so adjustment is possible - but rarely necessary. you will need to drive around for a bit, for the ECM to re-calibrate.
Runs a little better, but still stutters at the beginning of each shift and at cruising speed, although not too bad at the latter. The TPS went on without any problems, so that's a plus for my temperment. bb
How would motor mounts affect acceleration? Incidentally, all motor mounts were replaced about 15,000 miles ago. They shouldn't fail that quickly, should they? Thanks! bb
PD, I'm going to take it into a diagnostic expert nearby, since I've done everything that is within my reach. I don't want to go in uncharted territory and really screw something else. I wrote another entry entitled "what else can I possibly do," or something to that effect, in which I document everything I've tried / replaced to date (idle air control valve, mass air flow, mass air temperature sensor, ) O2 sensor, fuel injectors, fuel pump (though I'm beginning to doubt the quality of the replacement), s sensor,spark plugs and wires, cap and rotor, Cardone remanufactured distributor; cleaned throttle body; throttle position sensor, air temp sensor, coolant temperture sensor, and ignition control module. My neighbor checked the ignition coil, and I'm taking his word that it tested ok The catalytic converter is only 15,000 miles old and was a stainless steel product I purchased from Summit, The muffler is a Flowmaster from WCF. Hopefully these two items live up to their hype. I'm thinking it must be some kind of fuel flow problem, since the stuttering occurs to greater and lesser degrees at every part of shifting and acceleration. Or it may be a vacuum leak, but I don't want to blow myself to eternity to find one (vacuum leak, that is). It's been very educational in my quest to find the problem, particularly since I am not much of a mechanic. I'll leave the intricate stuff to the very well regarded mechanic with whom I've made an appointment. Thanks, though, for all your help. You have always responded quickly and with great advice to my previous questions.
if you replaced the TPS, the voltage must be checked and adjusted within tolerance. the ECM calibrates at KEY ON and uses the base reference voltage as 0% TPS, unless the voltage at idle is over, iirc ~.530V. a voltmeter or scanner will help verify TPS voltage, if voltage is over ~.530V the engine will have trouble starting and part throttle hesistation, do to the ecm thinking theres an OFF IDLE condition
It's been a while since I posted this, but I installed the TPS without doing any of the calibration. The car runs great (especially after I replaced 2 AC Delco spark plugs that had cracked ceramic insulators). Should I still have the TPS calibrated to be on the safe side, or should I leave it as it is. Thanks, and Happy New Year! bb
If the TPS is just a potentiometer, calibration may not need a scanner or an OBD-1 connection. We should be able to measure voltages with pins and a common Digital VoltMeter (DVM) - like the perpetual freebie from Harbor Freight. Depending upon the wiring, you may have to trim away some insulation to access the wires. Stick a pin into the center (where the internal copper is) in each of the three wires. There should be a stable voltage (5? 12?) between two of them, then 0.5V between ground and the one that's connected to the potentiometer's wiper. You can't go wrong, because the voltage to the other connection will be many times greater.
As commented, if the torx screws pass through slotted holes, adjusting should be a snap - just slight rotation. I looked at one photo of a Fiero TPS and saw only round holes, so perhaps there's zero or little adjustment room.
Will that work?
If you're a bit paranoid, almost any glue or sealant will restore the wire's insulation.
[This message has been edited by notaguru (edited 12-24-2013).]
These posts are old, however, if anyone is still monitoring them or gets emails on new posts, please respond:
1986 V-6 Fiero
Engine will not idle. car has been sitting a long time, and probably has not been on the road for 6 or 7 years. It will run if I feather the throttle. All sensors on the engine have been replaced with new ones, including the oil pressure switch, fuel switches and relays. It has a new fuel filter also. Fresh gas, fuel pressure is between 35 - 40 PSI. New plugs, plug wires, rotor and cap.
Now, when I unplug the TPS, and start the engine, the engine will idle with no problem. It throttles well, however has a noticeable misfire. I am presuming that I need to change out the throttle Position switch. Someone, please confirm.
Does anyone know anyone with a fuel sender? I can't pay what the Fiero Store is asking for one. Please ask around to see if someone has a working unit. Thanks
