Gauge issues, Oil temp and pressure |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
Gauge issues, Oil temp and pressure |
NARP74 |
Oct 5 2021, 03:40 PM
Post
#1
|
Senior Member Group: Members Posts: 1,067 Joined: 29-July 20 From: Colorado, USA, Earth Member No.: 24,549 Region Association: Rocky Mountains |
The car came with two aux gauges that never worked, oil pressure and temp, connected to a VDO sender in the engine area. They would just bounce around all the time. The sender was loose in the holder so I tightened that a bit and then the pressure gauge started working, but not the temp. Now the pressure gauge just pegs at max as soon as I turn the key and gets stuck. I have to thump it to go back to 0 after I shut it off. The temp gauge is still no go.
Everything thing on this car is a new learning adventure. Help please... wiring issue, sender unit? Where to start? |
jcd914 |
Oct 5 2021, 03:56 PM
Post
#2
|
Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
Oil Temp and Oil Press come from different sensors.
The Oil pressure sensor is probably the sensor you tightened up, the mount needs to be secure and grounded or the gauge won't work. The Oil temperature sensor is on the bottom of the engine and the wire comes up through the engine shelf below the battery. Oil on a 914 is slow to warm up, so the gauge may look inop when it just hasn't warmed up enough to show on the gauge. Good luck Jim |
NARP74 |
Oct 5 2021, 04:10 PM
Post
#3
|
Senior Member Group: Members Posts: 1,067 Joined: 29-July 20 From: Colorado, USA, Earth Member No.: 24,549 Region Association: Rocky Mountains |
Oil Temp and Oil Press come from different sensors. The Oil pressure sensor is probably the sensor you tightened up, the mount needs to be secure and grounded or the gauge won't work. The Oil temperature sensor is on the bottom of the engine and the wire comes up through the engine shelf below the battery. Oil on a 914 is slow to warm up, so the gauge may look inop when it just hasn't warmed up enough to show on the gauge. Good luck Jim Any way to test either sensor? |
jcd914 |
Oct 5 2021, 04:16 PM
Post
#4
|
Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
Oil Temp and Oil Press come from different sensors. The Oil pressure sensor is probably the sensor you tightened up, the mount needs to be secure and grounded or the gauge won't work. The Oil temperature sensor is on the bottom of the engine and the wire comes up through the engine shelf below the battery. Oil on a 914 is slow to warm up, so the gauge may look inop when it just hasn't warmed up enough to show on the gauge. Good luck Jim Any way to test either sensor? Measure resistances but I don't know the specs. For Temp compare resistance both hot and cold For press compare resistance with engine running and without running. To verify either use a separate test gauge and measure actual Tempo or Press. Jim |
NARP74 |
Oct 6 2021, 07:14 AM
Post
#5
|
Senior Member Group: Members Posts: 1,067 Joined: 29-July 20 From: Colorado, USA, Earth Member No.: 24,549 Region Association: Rocky Mountains |
I see the VDO sender all over the place for sale, I never see a bracket for it. I see some are screwed directly into an engine where a sensor would go, mine is on a remote hose and then to a bracket that does not fit right. What bracket are these supposed to be in? Mine is very loose in the bracket.
|
Superhawk996 |
Oct 6 2021, 07:27 AM
Post
#6
|
914 Guru Group: Members Posts: 5,834 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
I see the VDO sender all over the place for sale, I never see a bracket for it. I see some are screwed directly into an engine where a sensor would go, mine is on a remote hose and then to a bracket that does not fit right. What bracket are these supposed to be in? Mine is very loose in the bracket. Sender on remote hose is the better soution vs. mounting on engine on cantilevered brass tubes that will eventually fail. Stay with the remote hose. There is no purpose built bracket offered by VDO that I've ever seen. This is your task with aftermarket parts. It's up to you to modify them to your purpose. |
Dustin |
Oct 6 2021, 07:43 AM
Post
#7
|
Member Group: Members Posts: 111 Joined: 19-August 10 From: Woodland Hills, CA Member No.: 12,072 Region Association: None |
Without knowing the ohm spec, you can probably ohm it, then hit it with a heat gun for a minute and re test it. I believe the resistance should change. Just be careful not to melt anything.
Or disconnect it and connect an ohm meter and start your car. You should be able to watch the resistance change as your car warms. |
rhodyguy |
Oct 6 2021, 09:02 AM
Post
#8
|
Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,080 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
Skip the heat gun and use boiling water. Verify the temp with an 'instant read' kitchen thermometer. You won't melt anything.
|
barefoot |
Oct 6 2021, 09:22 AM
Post
#9
|
Senior Member Group: Members Posts: 1,275 Joined: 19-March 13 From: Charleston SC Member No.: 15,673 Region Association: South East States |
FOR OIL TEMP there are 2 different sensors,
short one for 120 or 150 Degree C and long one P/N 039 919 260 for 200 Degrees C used on 1973 & later cars My 1976 has the oil temp in the combo gauge along with fuel level & not on an aux gauge and it reads OK using the long sensor. |
slivel |
Oct 6 2021, 12:07 PM
Post
#10
|
Old car....... older driver Group: Members Posts: 509 Joined: 10-July 04 From: San Diego Member No.: 2,332 Region Association: Southern California |
FOR OIL TEMP there are 2 different sensors, short one for 120 or 150 Degree C and long one P/N 039 919 260 for 200 Degrees C used on 1973 & later cars My 1976 has the oil temp in the combo gauge along with fuel level & not on an aux gauge and it reads OK using the long sensor. Is that really 200 C? That's 392 F. Pretty hot for oil temp. |
barefoot |
Oct 6 2021, 01:26 PM
Post
#11
|
Senior Member Group: Members Posts: 1,275 Joined: 19-March 13 From: Charleston SC Member No.: 15,673 Region Association: South East States |
FOR OIL TEMP there are 2 different sensors, short one for 120 or 150 Degree C and long one P/N 039 919 260 for 200 Degrees C used on 1973 & later cars My 1976 has the oil temp in the combo gauge along with fuel level & not on an aux gauge and it reads OK using the long sensor. Is that really 200 C? That's 392 F. Pretty hot for oil temp. That's the MAX the sender id capable of, not expected oil temp's |
Rick986 |
Oct 6 2021, 03:21 PM
Post
#12
|
0-60 in 14 seconds! Group: Members Posts: 141 Joined: 31-August 21 From: NE Ohio Member No.: 25,869 Region Association: Upper MidWest |
Try replacing the temp wire from the sending unit back to its connection under the battery tray. That fixed mine!
|
930cabman |
Oct 6 2021, 05:29 PM
Post
#13
|
Advanced Member Group: Members Posts: 3,066 Joined: 12-November 20 From: Buffalo Member No.: 24,877 Region Association: North East States |
I see the VDO sender all over the place for sale, I never see a bracket for it. I see some are screwed directly into an engine where a sensor would go, mine is on a remote hose and then to a bracket that does not fit right. What bracket are these supposed to be in? Mine is very loose in the bracket. Sender on remote hose is the better soution vs. mounting on engine on cantilevered brass tubes that will eventually fail. Stay with the remote hose. There is no purpose built bracket offered by VDO that I've ever seen. This is your task with aftermarket parts. It's up to you to modify them to your purpose. Thanks for the tip, I was about to connect an oil pressure gauge to a brass extension with a couple ell's and keep the idiot light. 1/8" brass does not have much strength. |
NARP74 |
Oct 8 2021, 02:21 PM
Post
#14
|
Senior Member Group: Members Posts: 1,067 Joined: 29-July 20 From: Colorado, USA, Earth Member No.: 24,549 Region Association: Rocky Mountains |
Got a temporary ground worked out for the bracket. Things are better and worse. The light on the dash is working, goes on and off. The pressure gauge side of the VDO sender has an issue. The gauge is pegged as soon as you turn the key, never comes down and has to be wacked to drop back after the car is turned off. This happens even with the wire disconnected from the sender. How can I test the gauge to see if it is bad? What else would cause the gauge to max out on start?
Got the temperature gauge working, it was a failing connection under the battery tray. broken wire inside a tape joint. Warmed the engine up and saw it climb to 180 just to check it. |
NARP74 |
Oct 14 2021, 11:41 AM
Post
#15
|
Senior Member Group: Members Posts: 1,067 Joined: 29-July 20 From: Colorado, USA, Earth Member No.: 24,549 Region Association: Rocky Mountains |
What would make the gauge peg as soon as the key is turned? Is that a voltage short? If I pull the + wire it does not do that but wont work correctly. What am I looking for?
|
Lo-Fi Version | Time is now: 19th May 2024 - 09:19 PM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |