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914World.com _ 914World Garage _ installing gauges
Posted by: 914 RZ-1 Jul 15 2016, 02:56 PM
I got oil pressure and oil temp gauges. The instructions are generic and I'd like some specifics about how to install them on my 1.7L '72. Sorry if these seem obvious; I've never done this before.
1. Standard ground or floating ground? I'm leaning toward floating because it looks obvious how to attach the ground. On the standard ground, how do I attach the gnd wires?
2. What do I attach the wire from the gauge light socket to the light switch to? The headlight switch? Which connector?
3. Which fuse do I use for power? #9?
4. I figure I will just attach grounds to a screw on the body, either an existing one or a new one.
5. What is the "switched +12v" light shown in the instructions? The dummy light?
6. Does the oil pressure sensor get installed where the current oil pressure switch is by the distributor? Doesn't appear to be any room, but I'll need to move some hoses, etc out of the way.
7. Where does the oil temp sensor go? The instructions state that it can replace the drain plug. Is this correct?
8. Where is the best route for the wires? I was thinking thru the middle along where the other wiring harness is located. What should I do with them in the engine compartment: zip tie them to other wires, or let them hang free, or what?
If anyone has done this and has pictures or a more detailed description, I'd appreciate it.
Attached thumbnail(s)
Posted by: TeenerTech Jul 16 2016, 10:55 AM
where are you mounting the gauges?
if your mounting them in a center console there is already wires for power, ground, switched power, oil temp, and the blk/blu wire for gauge illumination.
for the oil pressure sender, the sender will not fit in the existing hole you have to remove the oil pressure switch next to the dizzy and use hose to mount the sender on the fan housing or wherever you decide.
Posted by: 914 RZ-1 Jul 31 2016, 04:09 PM
I'm mounting the gauges under the dash with a 2 gauge bracket. There is no center console. Looks like I'll be adding wiring, but someone confirm this.
What do you mean by "next to the dizzy"?
What kind of hose should I use?
Thanks for the pictures.
I'll try to get to this the next few days and see if I can answer my own questions.
Is there no thread on this already? I tried to search but wasn't able to find anything. Or is this so easy no one ever has to ask? 
Posted by: GeorgeRud Jul 31 2016, 07:39 PM
Unless you use the ashtray, this makes a convenient mount using the VDO rubber bracket. Just cut off the angled top and then use the ashtray mounting holes to attach the bracket.
Posted by: 914 RZ-1 Aug 6 2016, 05:48 PM
Here's what I think I will do:
WIRING
1. 3 connections for gauge: wire from gauge to #8 or #9 fuse, wire from gauge to ground, wire from gauge to sender. Seems like this will work.
2. Sender grounded to either the engine block or a wire to the metal somewhere.
3. For illumination, I will tap into the existing illumination wires and connect them to the gauge. I will look on the fuse box to see where these connect and maybe connect them there instead.
I was going to attach them to the light switch, but I'm not sure where; the Haynes wiring diagram was hard to figure out.
PRESSURE GAUGE
4. I need an extension for the pressure gauge. I went to get one like the one shown in one of the images in this thread (metal coated rubber hose with threaded fittings on either end). The thread on the sender appears to be a M10 x 1.0. but it is tapered. The FLAPS had fittings that were close, but not quite. Apparently there is a non-metric pipe size that fits, but I was not comfortable with this; I don't want to strip the threads or screw (pun intended) them up.
[color=#FF0000]
Where can I get metric fittings for this?[/color]
Posted by: 914 RZ-1 Aug 6 2016, 05:50 PM
Unless you use the ashtray, this makes a convenient mount using the VDO rubber bracket. Just cut off the angled top and then use the ashtray mounting holes to attach the bracket.
That is an interesting idea! Thanks. I was going to get one of those cup holder ashtrays one of these days.
Posted by: 914 RZ-1 Aug 6 2016, 05:52 PM
where are you mounting the gauges?
if your mounting them in a center console there is already wires for power, ground, switched power, oil temp, and the blk/blu wire for gauge illumination.
for the oil pressure sender, the sender will not fit in the existing hole you have to remove the oil pressure switch next to the dizzy and use hose to mount the sender on the fan housing or wherever you decide.
I just figured out that "dizzy" is distributor! Duh.
Where did you get the fittings for the hose? The fittings on the sensor are tapered and metric. My FLAPS didn't have anything that fit properly (they had some pipe threaded ones that were close, but...)
Where are the wires on the sender, by the way? I can't see them in the picture.
Posted by: TeenerTech Aug 6 2016, 06:34 PM
You can get the hose from Auto Atlanta and the wiring ( on the sender WK goes to factory light, G goes to your gauge) if you use a rubber extension you will need to ground the sensor if you use the steel braided hose it will ground through the hose to the engine.
As for the wiring fuse 9 is your switched power, the illumination wires go from the light switch to the gauges (no fuse) it is a black wire with a blue stripe you can ether tap on at the switch or at the gauge.
Posted by: 914 RZ-1 Aug 9 2016, 11:23 AM
You can get the hose from Auto Atlanta and the wiring ( on the sender WK goes to factory light, G goes to your gauge) if you use a rubber extension you will need to ground the sensor if you use the steel braided hose it will ground through the hose to the engine.
As for the wiring fuse 9 is your switched power, the illumination wires go from the light switch to the gauges (no fuse) it is a black wire with a blue stripe you can ether tap on at the switch or at the gauge.
Is there any other source for the adapter fittings? The hose I can get at my FLAPS, but the fittings are metric and tapered (like pipe thread). I've called around and can't find a source.
Has anyone used regular (non-tapered) metric fittings? The FLAPS (and some other sources-the Samba, etc.) all say using the closest English size will work, since the threads are so close, but I'm hesitant. Won't using a non-tapered male thread in a tapered female hole screw something up? Will it be tight enough?
Posted by: Mike D. Aug 9 2016, 01:18 PM
Jeff, I have a extra brake hose you can use. I know it fits the sender, but you'll need to find a male to male fitting for the case to hose. Maybe Metric Specialties?
Posted by: 914 RZ-1 Aug 9 2016, 01:43 PM
Jeff, I have a extra brake hose you can use. I know it fits the sender, but you'll need to find a male to male fitting for the case to hose. Maybe Metric Specialties?
Thanks, Mike, but I got the parts at Bouquet Auto. I just decided to get the NPT fittings. They are really close. The people there said it would work, just put them together finger tight with Teflon tape then give them a small, 1/8 of a turn to seat them.
Metric Specialties didn't have anything. I called or looked at: McMaster-Carr, Graingers, Fastenal, Swagelok, McFadden-Dale, Empi, cip1, and a few other places on the internet. I even called a plumbing supply place.
I emailed Auto Atlanta and asked about the threads on the kit they have. They want $64. Still haven't heard anything.
What did you use from the case to the hose?
Posted by: Carl456 Aug 9 2016, 04:38 PM
Following along quietly....
I have a vacuum guage as well that will be added but great help so far.
Posted by: 914 RZ-1 Aug 20 2016, 02:33 PM
Following along quietly....
I have a vacuum guage as well that will be added but great help so far.
Stay tuned. I think I might have found a better solution.
Posted by: Harpo Aug 20 2016, 06:30 PM
I threaded an 1/8 NPT fitting down in to my block. The adapter had -4AN fitting on the other end. Then I used a female/female -4AN 12 inch hose. Then I used a second -4AN to 1/8 NPT adapter (male/Male) to a 1/8 NPT (female female) then the VDO sender.
David
Posted by: cuddyk Aug 20 2016, 06:50 PM
I bought this kit. Has everything you need, including the right fittings, and is beautifully machined.
http://www.42draftdesigns.com/vw-audi-oil-pressure-relocation-kit/
As for the wiring, you can also try running your wires down under the carpet to the factory console harness (if your car is so equipped).
Posted by: 914 RZ-1 Sep 15 2016, 11:12 PM
So I got the gauges installed. I think the oil temp one works; I haven't got the car hot enough to register. The gauge starts at 120F and I only drove around the block, let the car cool, then fixed a connection. When I started the car a little while later (about 15 minutes) the gauge twitched a bit.
The oil pressure gauge maxes out immediately. I'm thinking this is an electrical grounding issue? I've got it grounded to the fan housing in the engine compartment.
Also, the gauge lights don't come on when I turn on the headlights. I tapped into 2 (one wire per gauge) of the black and purple wires that are for the gauge lights. Went from there to the gauge light. From the gauge light to ground on metal by knee board.
How do I remove the lights from the sockets? I pulled and they don't come out. They don't seem to twist either. I have VDO gauges.
I tapped into the same fuse (#9) as the radio for power to the gauges. Used a piggy back connector and put 2 wires on one spade, then into the fuse connection.
I'll try and post pictures later.
I'll also post what I found to use for a hose for the oil pressure sender.
Posted by: Mikey914 Sep 16 2016, 12:16 AM
Just finished the wiring harness for the appearance group gauge cluster (like OEM) for those that are interested they will be available for $58 each, and will plug into the factory wiring harness as shown. Doing these to promote the consuls, so if you are looking to add these in soon it will be a plug and play.
Posted by: N_Jay Sep 16 2016, 07:08 AM
I threaded an 1/8 NPT fitting down in to my block. The adapter had -4AN fitting on the other end. Then I used a female/female -4AN 12 inch hose. Then I used a second -4AN to 1/8 NPT adapter (male/Male) to a 1/8 NPT (female female) then the VDO sender.
David
Unfortunately the threads in the block are (or should I say, "were") metric and not 1/8 NPT.
You need to make a note that the blick has been "rethredded" for a NTP oil sensor ONLY.
Posted by: 914 RZ-1 Sep 16 2016, 08:34 PM
It seems the oil temp gauge works. I drove the car for 20 minutes and it went to almost 180. The sensor is under the car and not covered, so the air probably cooled it. I'm just going to assume the oil is hotter than that. Probably should get a temp gauge and try to measure it somehow. Any thoughts on how to do this?
The oil pressure still pegs to the right. I'm pretty sure I hooked it up right, but clearly something is wrong. Any ideas? 
The lights on the gauges don't work either. I tapped into the lighting wires for the other instruments. Does it matter which wire or wires I use?
Here are some pics:
Attached thumbnail(s)
Posted by: 914 RZ-1 Sep 16 2016, 08:41 PM
One other question: how do I pull out the bulbs on these gauges?
Posted by: Dave_Darling Sep 16 2016, 09:57 PM
Looks like the black part should pull out the back of the gauge housing; the bulb will be held in that.
Check to make sure that you have +12V on your lighting circuit when the headlights are on. Do the other instruments light up? The instrument light wires are mostly black with a blue stripe, except in 74+ cars (maybe also the earlier ones, not sure!) a gray wire connects in basically at the center console location.
Where is the oil pressure gauge signal wire hooked to? If you hooked it up to the stock sender, you'll get either full-deflection right or full-deflection left, I forget which. The stock sender is just an on/off switch for the light; you need the correct sender for the gauge.
--DD
Posted by: zambezi Sep 17 2016, 10:28 AM
I'll add to Dave that if you are using the correct dual terminal sender, then you obviously have it remotely mounted and you must be sure it is getting a good ground to the sending unit housing or it will do what you are seeing.
Posted by: 914 RZ-1 Sep 18 2016, 10:54 AM
I got the gauges to work!
I'm getting readings of about 220 F on the temp (running at 3-4K RPM on mixed roads-up, down, straight, etc) and about 50 psi on the pressure (at 3-4K RPM). It goes down a bit when the temp is higher and at idle.
The instructions that came with them are not entirely correct. Here's my wiring diagram:
Attached thumbnail(s)
Posted by: 914 RZ-1 Sep 18 2016, 10:58 AM
Looks like the black part should pull out the back of the gauge housing; the bulb will be held in that.
Check to make sure that you have +12V on your lighting circuit when the headlights are on. Do the other instruments light up? The instrument light wires are mostly black with a blue stripe, except in 74+ cars (maybe also the earlier ones, not sure!) a gray wire connects in basically at the center console location.
Where is the oil pressure gauge signal wire hooked to? If you hooked it up to the stock sender, you'll get either full-deflection right or full-deflection left, I forget which. The stock sender is just an on/off switch for the light; you need the correct sender for the gauge.
--DD
The other instruments do light up, but not very well. Do they have more than one light bulb and wire? Maybe I picked a bad one. I'll have to double check the wires I picked. I also thought maybe the taps I used didn't puncture the wire casing.
I have a black wire that has a bunch of black wires with a blue strip coming off it. I picked 2 of the blk/blu wires.
That's what I thought, but I must not be pulling hard enough. Are they press fit or some sort of snap?
Posted by: advman89 Nov 17 2021, 02:54 PM
One other question: how do I pull out the bulbs on these gauges?
Goooood question
Posted by: advman89 Feb 12 2022, 08:25 AM
I'm starting my own gauge journey today.
https://www.amazon.com/gp/product/B096VLD2QF/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
The fittings I picked up local at ChicagoConnection.
So far, have it everything snugged in there and will be starting the wiring, installing the temp sensor, etc.
(BTW--Those bulbs do just pull out...just need to apply a little leverage when your pulling). 
Posted by: emerygt350 Feb 12 2022, 01:26 PM
Just be careful you don't end up with GAS. Gauge accumulation syndrome..
Posted by: advman89 Feb 12 2022, 06:33 PM
HA! I'm trying to keep it classy!
Posted by: advman89 Feb 13 2022, 11:31 AM
Tackling the oil temp sensor. 1971 with a 1975 2.0L
I am replacing the Taco Plate with 914Werks' billet cover, aftermarket VDO sender.
The factory wire on there currently is black. and the bracket is attached to the taco plate (the tab / guard / crimped tail)...hoping that comes down easy.
In the meantime, I pulled the carpet on the tunnel and there isn't any connectors under there for a center console...so now what?
Just when I think I'm getting momentum...
Posted by: advman89 May 17 2022, 08:53 PM
I have everything operating..except the pressure gauge pegs to the right every time. I've tried several grounds:
1-gauge grounded under the dash (to the bolt holding the climate control unit).
2-I've tried several scenerios to ground the sender:
it's mounted to the location on the fan housing using a metal capacitor bracket....that should do it!
I've tried running a wire to the primary ground next to the battery to the sender housing (and tried the oil line bolt.
The other night on one of my shake down laps, when the car was warmed up, when I would come to a stop-the OIL light came on. As soon as I started rolling, it went off. Was slightly dimmed at one point.
Checked the oil...she's full.
I didn't need to run a ground wire from the sender to the gauge, did I?
Stumped!
I got the gauges to work!
I'm getting readings of about 220 F on the temp (running at 3-4K RPM on mixed roads-up, down, straight, etc) and about 50 psi on the pressure (at 3-4K RPM). It goes down a bit when the temp is higher and at idle.
The instructions that came with them are not entirely correct. Here's my wiring diagram:
Posted by: 930cabman May 18 2022, 01:51 PM
Are you using the factory oil pressure sender?
Posted by: advman89 May 18 2022, 04:07 PM
No. I'm using a VDO dual pole sending unit...it's in a post just before my last one.
Posted by: FlacaProductions May 18 2022, 05:26 PM
The dual pole senders trip the oil light “early” at a higher point than the oem sender so the fact you see the light coming on isn’t unexpected.
Posted by: advman89 May 19 2022, 11:43 AM
Good to know on tripping the light early.
...now to get this gauge from Pinning immediately when I turn the key.
Posted by: Retroracer May 19 2022, 02:04 PM
On the oil pressure gauge pinning issue, suggest the following:
1) disconnect the sender at the GAUGE end. Does the gauge still go to full scale?
- if YES, then somethings wrong with the gauge or your connections to it; make sure the gauge case is connected to chassis
- if NO, then go ahead and connect the sender wire again
next:
2) Gauge should still be indicating full scale (incorrectly). Disconnect the sender at the SENDER end. Does the gauge still go to full scale?
- If YES, then you have a wiring issue, possibly sender wire is short to chassis
- if NO, then you have a dodgy sender OR wrong sensor / gauge combo
You might want to double check the connections at the sender end; swapping the switch and sender connections won't harm things but will exhibit funky behavior..
Hope this helps / makes sense
- Tony
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