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#1 |
Registered Member
Join Date: Nov 2000
Location: Maple Ridge B.C. Canada, The Best Place In The World
Posts: 871
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![]() well, i thought my throttle positioning sensor was my problem, so i purchased a brand new one.
what was happening, was the tps was showing 4.79 volts. i tested all 3 wires grey wire 4.79ish volts grey/white wire 4.79 volts also brown wire 5 volts. what could the problem be? i replaced the sensor and ive still got the same readings. i can not think of anything else that could be the problem. if someone else could make a suggestion, that would be greatly appreciated. Thanks, Kris
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1984 Bronco II, 36" Michelin Military Tires, 95 EFI 5.0, NP435 Tranny, NP208 Doubler, NP205 Transfer Case, Fill Size Solid Dana 44 Front End, WH Progressive Rate Rock Crawling Coils, Bronco 8.8 Rear, Skyjacker Softride Leafs, 5.13 Gears, Detroit Locker. Final Crawl Ratio Of 175:1 88 GT Best 60ft. 2.181 Best ET 14.350 Best MPH 98.01 ~WRECKED!!!!~ |
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#2 |
Registered Member
Join Date: Mar 2003
Location: Saint Louis, MO
Posts: 634
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![]() If the car runs normally, it is the method your using to measure the voltage. YOPu should be measuring between two of those wires, but I don't know those color codes off the top of my head like the Fox cars.
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Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/ |
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#3 |
Conservative Individualist
Join Date: May 1997
Location: Wherever I need to be
Posts: 7,487
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![]() On your SN95-model 5.0 TPS, the first grey wire is the ground, the second grey wire (with the white stripe) is the test wire and the brown wire is the 5v source.
So, to test your new TPS you would put the negative lead on your voltmeter to a good engine ground - or the first grey wire. Then you would put the positive voltmeter lead to the middle grey (with white stripe) wire. You already know that you should be reading around .98-.99 volts and that you should be taking your reading with the engine off, ignition on, right? Here's a photo to help you out: http://www.muscularmustangs.com/tps2.jpg Hope this is of some help to you. ![]()
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5.0 Mustang Owner 1990 - 2005 |
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#4 |
Registered Member
Join Date: Nov 2000
Location: Maple Ridge B.C. Canada, The Best Place In The World
Posts: 871
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![]() thanks everyone. measured it properly the first time, unfortunately for me, what could be causing the super high voltage?
yes i tested it key on engine off, thats the first thing everyone suggests, but ive checked tps successfully on many foxbodies, and now this motor. could i have a wire shorting out or something? it just makes no sence to me. could my computer be fried? i hope not because i just replaced this one, but oh well, or could it be a relay or something?
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1984 Bronco II, 36" Michelin Military Tires, 95 EFI 5.0, NP435 Tranny, NP208 Doubler, NP205 Transfer Case, Fill Size Solid Dana 44 Front End, WH Progressive Rate Rock Crawling Coils, Bronco 8.8 Rear, Skyjacker Softride Leafs, 5.13 Gears, Detroit Locker. Final Crawl Ratio Of 175:1 88 GT Best 60ft. 2.181 Best ET 14.350 Best MPH 98.01 ~WRECKED!!!!~ |
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#5 |
Registered Member
Join Date: Mar 2003
Location: Saint Louis, MO
Posts: 634
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![]() Sounds like you lost the ground on the return wire from the TPS then - which would make both wires test the same referenced to ground.
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Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/ |
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#6 |
Moderator
Join Date: Sep 1998
Location: Grand Rapids, Michigan, USA
Posts: 1,001
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![]() I agree, kind of. I'm willing to be there's either a break in the wiring, causing a short between the +5V rail and the signal return line, or there's an internal problem in the computer (highly unlikely). If BOTH LINES are at the same voltage as you state, try a continuity test between the two to see if they're shorted together, and go from there.
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Capri306, Moderator The Mustang Works Online 1979 Mercury Capri 1987 5.0L Mustang LX Notchback 1993 5.8L Eddie Bauer Bronco ![]() |
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#7 |
Registered Member
Join Date: Nov 2000
Location: Maple Ridge B.C. Canada, The Best Place In The World
Posts: 871
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![]() well i unhooked the tps sensor, and tested the ground wire and the test wire.
with the tps unhooked, the test wire showed 0 volts, the ground however, showed like 3 and a bit volts? where should i look now?
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1984 Bronco II, 36" Michelin Military Tires, 95 EFI 5.0, NP435 Tranny, NP208 Doubler, NP205 Transfer Case, Fill Size Solid Dana 44 Front End, WH Progressive Rate Rock Crawling Coils, Bronco 8.8 Rear, Skyjacker Softride Leafs, 5.13 Gears, Detroit Locker. Final Crawl Ratio Of 175:1 88 GT Best 60ft. 2.181 Best ET 14.350 Best MPH 98.01 ~WRECKED!!!!~ |
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#8 |
Factoy Five Roadster
Join Date: May 2000
Location: Sevier Co,Tennessee
Posts: 1,681
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Frank |
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#9 |
Moderator
Join Date: Sep 1998
Location: Grand Rapids, Michigan, USA
Posts: 1,001
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![]() Mr. 5.0 and mustangII460, both made excellent posts....but....
WTF is this "TEST WIRE" you keep referring to??? There is no such thing as a "test wire." Do you mean the +5VDC, ground, or signal return??? The black wire should be GROUNDED through the harness, at the computer's chassis, then to vehicle (and battery) ground. Take some pictures or something; you're confusing the heck outta me, dude. ![]() You should be reading voltage like this: 1. Connect the NEGATIVE lead of the DVOM to the NEGATIVE terminal of the battery. 2. Make sure the DVOM is set to read "Volts," automatic scaling if possible. 3. Turn the ignition switch ON (engine running position but without the engine running). 4. Leave the TPS connected! 5. Using a hat pin, pierce the wire insulation far enough so the pin is almost sticking through the other side of the insulation, one wire at a time; do it on an angle of about 30 degrees from the wire's axis, so you save your fingers. 6. Connect the POSITIVE lead of the DVOM to the hat pin. 7. RECORD the voltage you see on the DVOM. 8. FOR THE LOVE OF GOD, record the color of the wire with the corresponding voltage. Present your findings here, and I'll be glad to help more.
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Capri306, Moderator The Mustang Works Online 1979 Mercury Capri 1987 5.0L Mustang LX Notchback 1993 5.8L Eddie Bauer Bronco ![]() |
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#10 | |
Registered Member
Join Date: Mar 2003
Location: Saint Louis, MO
Posts: 634
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![]() Quote:
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Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/ |
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#11 |
Registered Member
Join Date: Nov 2000
Location: Maple Ridge B.C. Canada, The Best Place In The World
Posts: 871
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![]() i have done exactily as you explain.
with everything connected, the middle grey/white stripe wire(i refered to it as the test wire because that is the wire you are supposed to test the tps voltage from) shows exactily 4.92 volts. the top grey(ground) shows 4.92 volts also the bottom brown wire shows the correct 5 volts. i did everything else as you have explained
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1984 Bronco II, 36" Michelin Military Tires, 95 EFI 5.0, NP435 Tranny, NP208 Doubler, NP205 Transfer Case, Fill Size Solid Dana 44 Front End, WH Progressive Rate Rock Crawling Coils, Bronco 8.8 Rear, Skyjacker Softride Leafs, 5.13 Gears, Detroit Locker. Final Crawl Ratio Of 175:1 88 GT Best 60ft. 2.181 Best ET 14.350 Best MPH 98.01 ~WRECKED!!!!~ |
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#12 |
Registered Member
Join Date: Mar 2003
Location: Saint Louis, MO
Posts: 634
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![]() Some times a graphic can help. If the ground for the computer or the signal return trace on the EEC board is fried, or both, the vref does not have a ground reference in the EEC where it needs to be and the only way to get a vref reading is to use the block as the ground reference.
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Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/ |
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#13 |
Moderator
Join Date: Sep 1998
Location: Grand Rapids, Michigan, USA
Posts: 1,001
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![]() If the TPS is connected and he's getting these numbers, I'm agreeing, there's got to be a wiring or other connection problem. A poor or nonexistant ground connection could be the culprit as well, so let's check those ground connections! Make sure there's less than 0.5 ohm between the battery ground and the EEC's chassis, and even then be sure the connection is sound.
Whether it's an internal (EEC) or external (wiring) problem, it's going to be some good ol' harness diving and tracing.....not fun, but necessary. Since you mentioned it happened all of a sudden, I'm thinking that you have a pinched wire somewhere, as happens in so many transplants. I just don't see how you're getting almost 5V on the TP's signal line (going back to the EEC) if the TPS is connected and there aren't any shorts in the system....usually this happens if the TPS is shorted internally. If it's an identical voltage to the +5V line, I'd say that's strong evidence that you indeed do have a short across lines somewhere, somehow. Do you have a spare computer you could try temporarily, just to rule out a bad computer? With the TPS connected, you should have ~5V+ on the Vcc (or whatever you wanna call it ![]()
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Capri306, Moderator The Mustang Works Online 1979 Mercury Capri 1987 5.0L Mustang LX Notchback 1993 5.8L Eddie Bauer Bronco ![]() |
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#14 |
Registered Member
Join Date: Nov 2000
Location: Maple Ridge B.C. Canada, The Best Place In The World
Posts: 871
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![]() IT WAS A GROUND PROBLEM!!! i grounded the ground wire off the tps connector, and checked the tps voltage, it was at 1volt constantly, thanks guys!!!
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1984 Bronco II, 36" Michelin Military Tires, 95 EFI 5.0, NP435 Tranny, NP208 Doubler, NP205 Transfer Case, Fill Size Solid Dana 44 Front End, WH Progressive Rate Rock Crawling Coils, Bronco 8.8 Rear, Skyjacker Softride Leafs, 5.13 Gears, Detroit Locker. Final Crawl Ratio Of 175:1 88 GT Best 60ft. 2.181 Best ET 14.350 Best MPH 98.01 ~WRECKED!!!!~ |
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#15 |
Registered Member
Join Date: Mar 2003
Location: Saint Louis, MO
Posts: 634
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![]() told ya
![]() Glad to hear your running again.
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Tom (Torque) Moss 88Gt 5spd Vert, FLowmaster Catbacks, stock cam advanced 4° @ 108.5° ICL, NMRA prepped GT40P heads 1.85/1.55 valves and 1.7 rockers, MAC P headers Jet-Hot coated, 97 Exlporer intake (ported lower), TB and injectors. 277RWHP/330RWTQ (SAE). http://www.fastlanecars.com/ |
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#16 |
Registered Member
Join Date: Mar 1999
Location: Calumet City, IL, USA
Posts: 39
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![]() Glad you got it fixed!!!
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Larry Bosley 1995 Mustang GT(R.I.P.) 2002 GT |
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#17 | |
Registered Member
Join Date: May 2010
Posts: 1
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![]() Quote:
I did this on my car and the tuner just changed the parameter on a Diablo Chip and the problem was solved. Good luck with this .... |
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