Fitting aftermarket gauges...

[e34.535i.sport]

My new 52mm vacuum/boost gauge just arrived so as you can imagine I'm eager to fit it! Here's an initial snapshot...

I know it's nothing special but I'm just interested to see how the engine's doing vacuum-wise and how the supercharger's doing boost -wise!

I'm planning on putting it inside the drivers side air vent:


Now I understand the pro's and con's of this as I've given it a fair bit of thought. The reasons for doing it this way are mainly:
1. I want to give it a fairly 'factory' finish (as much as possible).
2. It's easy to view.
3. There's a wire loom passing right behind the vent.
4. It's close to the ignition and the firewall.

The negative issues are obvious and I'm willing to make some sacrifices to get it how I want it.


Anyway, athough it did come with 'instructions' :P


I'm not too sure how to deal with the electrical side? It's difficult to read on there so here's what it says about the three wires:
BLACK WIRE - "Connect to good ground"
ORANGE WIRE - "Connect to 12v lighting"
RED WIRE - "12v ignition switch"

Can anyone explain to me in laymens terms what wires I'm looking for? Do they have specific colours or way's of identifying them? (Please excuse my ignorance here - I'm useless with anything electrical! I did research this online thoroughly but still not too sure here...)

I'm going to document the process and post a write up once it's in... Hopefully be some use to someone in future.

[e34.535i.sport]

Ok - I've made a start on the fitment of the gauge into the vent housing using a small sheet of plastic and a couple of wires... Here's what it looks like so far:












It's not perfect yet... The vent is a funny shape so it's difficult to get the plastic cover to fit perfectly. I might even treat this as a prototype depending on what it looks like once I've used some black silicone sealant around the edge at the back to seal it up.

I'm still struggling with the wires however Any words of wisdom for me?!

[e34.535i.sport]

Just been messing around with it... 9v Battery seems to work!



Looks like it's not quite calibrated to 0 though... Not sure if this gauge has a starting sequence when wired up properley in which it does a full sweep and then begins at zero :S

[Tiger]

Orange light, they want you to hook up to other dash light circuit so when you turn on the light, it will light up the gauge.

Red wire... they want you to hook up to switched positive... like radio so the gauge only work when ignition is in on position.

[M20Turbo]

Good idea, I have been wanting to add a boost/vacuum gauge for some time. I had not thought of the air vent as a location.

[genphreak]

I think you're fitting it in the wrong car dude, isn't that panel from a toyota or something?

[e34.535i.sport]

Hahaha no sorry Genphreak I swapped the e34 for an XJR (1995) a while back

M20turbo - Yeah I was just going to buy a testing gauge initially to see what the condition of the engine is but after some research it seems it can be very useful to monitor the vacuum under different conditions to identify/predict problems! (Also be nice to see the boost when the supercharger kicks in!

Cheers Tiger - I'm still unsure on this orange wire however as the gauge is completely black when off, then fully lit up when on (using just the black and red wires) ... I just can't see what will change with the orange wire? Please excuse my ignorance if it's blatantly obvious I just know nothing about electrics at all!

Write up o fitting to follow!

[e34.535i.sport]

Hi guys - Got round to sorting out most of the remainder of the install last night and tried to document it as much as I could so here goes!

POSITION OF THE GAUGE
For me a stealthy install was the main objective. It's only my personal prefence but I don't like the look of aftermarket parts in the engine bay and in the cabin if it can be avoided. I also thought that the drivers side air vent was good for a variety of reasons (explained earlier) but ease of install and the inconspicuousess (yes it's a word!) were both major factors. Having already sorted the position of the gauge strategically the rest of the fitting procedure was a peice of cake. At first it seemed a bit daunting but it took me less than an hour to get everything the way I wanted it (and I'm quite fussy when it comes to my car!) :P


THE GAUGE POD
The gauge pod (vent) just needed finishing off by using some black silicone sealant on the back of the black plate which holds the gauge in place just to make sure it didn't move (but could be removed if necessary!). Just to reiterate I pulled the vent out of the dash, snapped the slats out of the middle, removed the back blanking plate, used a peice of cheap plastic to fill in the front of the vent then cut a hole in it big enough for the gauge. I also put in two wires (you can see these in one of my previous posts) to stop the plastic plate from falling through the vent (then applied the sealant). Oh and I also drilled some small holes in the back to put the wires/hose through later (if necessary).


FITTING THE VACUUM HOSE
Now, this is pretty specific to my install but I found an existing hole in the firewall which was near the drivers vent and pierced a hole in the plastic cover which I threaded the vacuum hose through... Here's some visual:







Lucily enough this sent the hose right through to where I wanted it... I found it easily when I looked up in here:



The other end of the vacuum hose I sent along the firewall across towards the centre of the car (sticking it to an existing wire harness with cable ties!) and then down along the fuel rail so I could 'T' into the vacuum line that goes into the top of the manifold (and to the FPR). I had to have a torx peice to remove the plastic fuel rail cover here and I also unclipped the injector harness for easier access... Someone with skinny fingers might not need to do this! T-ing in to the manifold/FPR vacuum hose was easy due to the set up here, I didn't even have to cut the short vacuum hose and the one supplied with the gauge was the perfect length. You won't have a problem doing this so I won't dwell on this part. Here's some pic's though to support:






(Apologies on the pictures getting darker and darker... It was getting late!)

INSIDE THE CAR
Now that the vacuum line was all in it's just a case of finding the right wires to tap into for power/lighting. I've not quite been able to figure this out just yet so I cut a connector off an old smoke alarm and attached it to the red and b lack wires on the gauge... This way I can power the gauge using a 9v battery. I'll be honest and say this lights the gauge up fine so I can't see what use the orange wire is going to be, but when I find out I'll let you know!

Now just attach the wires (once you know which ones to attach) and put the vacuum line onto the back of the gauge (putting the wire in hot water for a little while will soften it enough to get it on easily) and away you go! Here's some preliminary pic's of my set up so far (not completely finished but getting there...)

[genphreak]

Sorry, I forgot you'd gone to the other side... the night photos are very draculaic! Nice mod, a panel begging for improvement that one. Nice clean gauge! Now you just need to make the rest of the dash suit

Is it worth cable tieing the gauge's pipes, just in case the pressure blows em off? LOL!

[whiskychaser]

3 pages of wiring diagrams for your motor here:
http://www.captainjaguarscathouse.co...%20Diagram.pdf
If you dont find what you want there at least it will tell you which wires NOT to cut into
Looks a proper job though John. You tried it out yet?