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| Fuel, Engine Temp or Oil Pressure gauges have problems? (Page 2/2) |
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theogre
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APR 18, 05:05 PM
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If people want buffs cheap... Likely wears out fast or faster but so does Dremel buffs for many jobs...
Amazon and likely others sell sets cheap.
Example: https://www.amazon.com/Roca...Dremel/dp/B075C72PGK
40 in 4 "grits" ~ $12 but different "colors code" then Dremel buffs...
Says "Brown 120Grit, Green 180Grit, Red 320Grit, Black 400Grit "
400 grit if true is less abrasive then Dremel Purple 320 Grit and safer for the copper.
was buying other Dremel stuff came up in list at bottom.
4Ref: When copying amazon links, cut off all after name/dp/pn Example: Polishing-Dremel/dp/B075C72PGK/ref=xxxxxxxxxxxxx cut off starting at /ref=
Even PFF autolink can/will edit what displayed but work right in the link code.
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theogre
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OCT 04, 01:00 PM
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Update to add testing data...
How to "test" fuel/oil gauge w/ Resistor...
Fuel: Test @ C502 on "Firewall" that often hinds under other wires goes thru the wall. Unplug & Test between Pink & Black wires. Make sure the plug is push down again after testing so exhaust doesn't burn it.
Oil: Pull sender plug @ test Tan wire to engine.
Short = Empty/0psi
45Ω = Half Scale
90Ω = Full Scale
Note: Gauges can see a bit Higher resistance from the sender even when working 100% & why Fuel gauge reads "over full" many times. "over full" mean just a little off of scale. Not Pegged when sender is unplugged/dead.
Standard Resistors can get close to above, like 42 or 48Ω, & "good enough" to point where a problem is.
Many don't have loose resistors & many things are make of "surface mount" parts now but often have access to old toasters, hair driers etc that can cut a piece of resistance wire to make these low Ω resistors.
How to "test" Temp gauge w/ Resistor...
Warning: Temp Gauge Sender is NTC resistor type but Is Not same resistor curve used by ECM in MAT/IAC or ECT. Do not trust nearly all charts posted here or elsewhere.
Unplug the sender, test wire to engine. Color of Wire varies per year/engine. Short the plug to ground to see light turn On or Gauge > max temp.
Sender/Test Resistance:
1365Ω @ 100°F 38°C
55Ω @ 260°F 127°C
Maybe make these out of "Volume" controls of old radios etc. But I think many max out @ 10,000Ω so need to add fix resistors.
Can test on the back of the dash or in other places but have to unplug the oil or fuel sender same as above. Not covering the details here.
If tested on the Dash, make sure isn't "12v" or can heat up or burn the resistors. Look carefully @ the clips on the back, if a clip shares copper w/ other clips etc then that clip is either "12v" or Ground. Test w/ Volt meter to car frame to make sure.[This message has been edited by theogre (edited 11-08-2023).]
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theogre
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NOV 08, 12:00 PM
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Example of Fuel gauge "reading" over full...
This is what I get nearly every time I fill the tank now after above fix w/ Engine Running because Sender is "pegged" @ End of Travel limit & reads ~ 91-92Ω @ C502.
Before you ask... & that's stopped filling @ first time the nozzle trips Off @ most stations. If you "stuff" the tank then you can "poison" the EVAP can or worse leaking liquid fuel out of iffy vents etc.
Note: Even GM used several Senders over just Fiero years. Then add TFS & other senders to replace bad senders.
So actual full Ω can vary over 90 to 93Ω when the sender is @ EoT
Engine Running vs Not means System Volts = output from the Alt vs Battery Volts & change gauge reading a little to be on Full mark more w/ engine Off.
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theogre
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NOV 10, 11:35 AM
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Bigger pic from an older thread to test gauges etc.
Example: you test Fuel sender @ C502 get 90Ω then pull C3 or the Gauge & read different then wiring have problems.
Can be the sender wire or iffy ground/power to the gauge make gauge reading off.[This message has been edited by theogre (edited 11-10-2023).]
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