Oil pressure
12-04-2005, 08:43 PM
#1
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Oil pressure
Got a new 84, auto. Oil pressure always reads 80 and oil temp is always low. Would this be a instrument problem or sending unit problem. Is there a chart to show ohms in relation to pressure. Also the tach works intermittently, where to start on troubleshooting.
12-04-2005, 08:52 PM
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Start with the factory service manual, available, HERE. It will contain volt and Ohm readings for the sending units. You may have bad sending units or they may be simply disconnected or the wiring defective. Trouble shoot for the problem before buying parts you MAY not need.
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12-05-2005, 10:59 PM
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I looked in the manual, the figures given are for the tester that makes the cluster display. By the way that looks like a handy tester, are they available.
12-06-2005, 08:49 AM
#4
Team Owner
Gordon Killebrew has some diagnostic tools available for the digi-dash.
As for the sensor problems - I would check the wiring harnesses very closely on these older vettes. The wire itself is prone to heat related failure. Add some chemical spills and problems arise........ The insulation will crack, chaffe and shrink around connectors. it is not pretty. These failures will lead to shorts and groundings.
As for the sensor problems - I would check the wiring harnesses very closely on these older vettes. The wire itself is prone to heat related failure. Add some chemical spills and problems arise........ The insulation will crack, chaffe and shrink around connectors. it is not pretty. These failures will lead to shorts and groundings.
12-06-2005, 11:21 AM
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Originally Posted by MBDiagMan
The likelihood of both sensors being bad is very remote.
Good luck,
Good luck,
Originally Posted by oldace84
What weight oil are you using. Change the oil.
Just my 2cents.
Good Luck.
Just my 2cents.
Good Luck.
RACE ON!!!
12-06-2005, 11:24 AM
#8
Le Mans Master
You don't need a tester - Pressure sender is fairly simple; rising in resistance as pressure increases. Disconnect the tan wire and ground it. Gage should read 0. If so, the wiring and cluster are good so replace the sender. If you want to check the accuracy of the display, pick up some resistors at Radio Shack. 90 ohms is 80 PSI; 45 ohms about half of that.
If grounding the lead doesn't get you 0, check the connection at the Bulkhead connector and from there to the Display - Pin A2 to C1 or check your Manual for the correct Pins. If the wiring is good, cluster is bad.
If grounding the lead doesn't get you 0, check the connection at the Bulkhead connector and from there to the Display - Pin A2 to C1 or check your Manual for the correct Pins. If the wiring is good, cluster is bad.
12-06-2005, 11:51 AM
#9
Le Mans Master
Just saw you also have LO on the Temp readout and a sparodic Tach - Temp sender works the other way - resistance decreases with Temp, so if you remove the lead and jumper it to ground, that should give you something above 300 degrees.
Possiblility that with both (Temp and Pressure) being out, Function Select switch is funky, though that usually gives you a Blank Display. Do the simple stuff first and repost if you can't find it.
Tach is little more problematic, but assuming it uses a filter, I'd guess that it needs to be replaced, though you can check for an a/c voltage on the side going to the dash.
Possiblility that with both (Temp and Pressure) being out, Function Select switch is funky, though that usually gives you a Blank Display. Do the simple stuff first and repost if you can't find it.
Tach is little more problematic, but assuming it uses a filter, I'd guess that it needs to be replaced, though you can check for an a/c voltage on the side going to the dash.
12-06-2005, 02:17 PM
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Originally Posted by SunCr
Tach is little more problematic, but assuming it uses a filter, I'd guess that it needs to be replaced, though you can check for an a/c voltage on the side going to the dash.
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