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#1
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Next two issues 70 T/A
Home stretch on resto of 70 T/A. Next issues: Oil pressure gauge not working. Sending unit is new and wire harness is new. I installed a mechanical gauge to oil filter housing port and PSI is perfect. Is there a way to test gauge as I did not not think they really went bad. #2, Volt meter not working (Gas gauge does) Is there a way to test this gauge too? Thanks.
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1970 T/A |
#2
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The oil gauge should read zero when key is on, engine is off.
If that is OK, unplug blue wire at the sending unit. The gauge should read full pressure. (I think on this one, at least way up) The voltmeter should have 12 volts to it, if it does, the ground wire/fitting may not be grounded?
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John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#3
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Up date on Oil Sending unit.
Conducted tests as follows:
Motor not running: Key off: Gauge pegged past high. Key on: Gauge at "0" Wire at sending unit unplugged, key on= Pegged past high Wire at sending unit unplugged and grounded; gauge reads "0" Motor running= gauge pegged past high all the time. Interpretation please? Thanks.
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1970 T/A |
#4
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Results direction please
Can someone interpret these results for me for my next move? Thanks.
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1970 T/A |
#5
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Not for sure, but I'd say the sending unit is wrong or not working correctly.
Seems to be acting like a non-gauge unit? (either on or off with amount of pressure) Is the sending unit an aftermarket unit? Is it a big unit?
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John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#6
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Got it at Oreilly Auto for about $20 and it is bigger than the original unit I had.
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1970 T/A |
#7
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The oil pressure sending unit is the shape of a birdcage with a single terminal coming out of the top of the unit.
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1976 LeMans B09 Freeway Enforcer, 455/M40 Smokey 1977 Trans Am, 400/M21 Black/Gold Bandit. 44K actual miles 2017 Sierra SLT 1500 Z71 4X4 2019 Canyon SLT Crew 4X4 |
#8
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sounds like you have wrong sending unit... The gauge works off of ground. let me explain... the gauge in the dash has no voltage (+12v) till the key is on....the ground is always there coming from the sending unit but it varies depending on how much signal the sending unit is letting thru.
so the sending unit is letting no ground signal thru. thus the gauge doesn't know what to do so it pegs out. If you could put a dial resister from ground to the wire at the sending unit then you could vary the resistance to the gauge and watch the gauge respond.. So as you varied the ground resistance to the gauge the needle would move.. make sense? My money is on wrong or bad sending unit.
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65 Mutant 1967 Firebird Fatass 70 Mutant II I want my driveway to look like I'm stuck in the 70's!!!! |
#9
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key on: When you ground the wire going to the sender the gauge should make a full deflection to high, like off the gauge. If the gauge is like this without grounding the wire then the sender wire is likely shorted to ground.
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1978 Black & Gold T/A [complete 70 Ram Air III (carb to pan) PQ and 12 bolt], fully loaded, deluxe, WS6, T-Top car - 1972 Formula 455HO Ram Air numbers matching Julep Green - 1971 T/A 455, 320 CFM Eheads, RP cam, Doug's headers, Fuel injection, TKX 5 Spd. 12 Bolt 3.73, 4 wheel disc. All A/C cars |
#10
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Thanks for the responses Gentlemen and I guess I will order a new Sending unit and take the other one back. Rock Auto shows 2 for a "gauge"; #1S6563 for $9.20 and a PS155 for $14.85. They dont show one from AC Delco so any opinion on either of these?
Thanks Dave
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1970 T/A |
#11
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Quote:
The original blew out on my '73 and was spilling oil due to the high oil pressure. Could not get one locally so I called Ames and got two $28.00 a piece. Part # FM472. Hope it helps. Jim |
#12
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Great news!
Replaced the P.O.S. Oreilly sending unit with one from Napa and now the oil pressure gauge works perfectly! Thanks guys!! On to the Volt gauge that always reads "0". I jiggled the connector on the back of the volt gauge and the gauge worked, indicating 15 volts for about 5 seconds before it quit. I removed the connector from the volt gauge and took a reading with my Volt meter at the orange lead and I had 12.5 volts with the key in the "on" position. Because there is 12 volts at the orange wire, I presume the gauge is bad? Can I replace just the volt meter with a newer one w/o replacing the "fuel" gauge? I do have another newer unit but I dont want to replace the fuel gauge as it is original to this 1970 and I dont want one that say "Unleaded". Thanks again.
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1970 T/A |
#13
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Make sure the ground wire on that volt guage IS going to ground.
If it's not grounded good it may have stray voltage on it keeping the guage from working. Clay |
#14
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Ground?
Do you know where the other end of the ground/black wire terminates? Thx QS. Dave
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1970 T/A |
#15
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Bad Volt gauge!
I plugged in my spare volt gauge and it worked properly so the original gauge is defective. Thanks everyone.
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1970 T/A |
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