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Glow Shift EGT hookup by Rat407 on 20 Jul, 2008 16:28
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Ok I did a search but couldn't find anything. I hooked up my new Glow Shift EGT gage per the instructions, Pink wire to pink temp probe wire, Blue wire to blue temp probe wire, black to ground, red to a switched 12 volts, I used a connection at the fuse block for that, it turns on when I turn the key on. and the yellow wire to a constant power, which I used the cigarette lighter power wire for that.
Here is the problem, when I turn the key on it pegs out to max EGT. So whats up with that?
Thanks. -
#1 by gigaz2 on 20 Jul, 2008 17:34
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Quote from: "Rat407"
Ok I did a search but couldn't find anything. I hooked up my new Glow Shift EGT gage per the instructions, Pink wire to pink temp probe wire, Blue wire to blue temp probe wire, black to ground, red to a switched 12 volts, I used a connection at the fuse block for that, it turns on when I turn the key on. and the yellow wire to a constant ground, which I used the cigarette lighter power wire for that.
Here is the problem, when I turn the key on it pegs out to max EGT. So whats up with that?
Thanks.
that can't be right
try to contact the manufacturer for advice, they can help you better. -
#2 by Turbinepowered on 20 Jul, 2008 19:40
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Yellow wire for a constant ground? The Cigarette lighter wire isn't a ground, that's a constant 12v supply.
I'm guessing you have a temperature compensated EGT gauge. Check that you have a solid ground connection, good clean contact.
Which connection at the fuse block did you use for your switched 12v? What terminal number, car model and year? -
#3 by Darkness_is_spreading on 20 Jul, 2008 20:09
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yeah you might have shorted out your EGT gauge. The red is probably switched 12V ground for the Illuminations and the yellow is for constant 12 V.. Just look at the instructions, the egt gauge is essentially a thermal resistor and will have a high resistance when hot and conduct less current and at startup the egt would be cool and the temp would rise the current would be high initially and then drop.....
This is the same principle in conductors over large spans, you run a 3 phase 3/0 gauge wire that can handle say 100 amps (primary 27 600V)line to neutral (Wye system). If it was really hot out the current would sag and you wold have phase imbalances and your lights would dim (Brownout).
So essentially check your wiring -
#4 by Rat407 on 21 Jul, 2008 01:37
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I fixed my post, I meant to say the Yellow wire for constant power which I hooked up to the cig lighter.
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#5 by saurkraut on 21 Jul, 2008 05:57
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Quote from: "Rat407"
I fixed my post, I meant to say the Yellow wire for constant power which I hooked up to the cig lighter.
If your cigarette lighter is powered without the key in the ignition, you may run the battery down if you park it for a few days.
There are switched 12 V sources on the back of the fuse box. Get a simple multimeter, or a test light and find them.
Worst case, you can use the injection pump stop plunger wire for power as that is switched. -
#6 by jimfoo on 21 Jul, 2008 06:29
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It should peg to max, then go back down to whatever the current temp is. If it stays pegged, it is bad and should be returned. It is supposed to be a self test.
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#7 by Vincent Waldon on 21 Jul, 2008 08:59
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Quote from: "saurkraut"
Worst case, you can use the injection pump stop plunger wire for power as that is switched.
... although not fused... so caution is warranted !!
On MK2s there's a big fused heavy wire that feeds the rear window defogger switch and another that feeds the defrost fan... lots of power and it's close to where most people install their accessories.
Having said that, I wouldn't use it for voltage-sensitive gauges like oil temp and pressure... depending on your grounds the dip in voltage when you turn on the rear defogger or fan could impact the reading.
My cars all have pimped glowplug wiring so a very direct and fused line to the battery for all add-ons and do-hickies. -
#8 by KTZed on 21 Jul, 2008 17:32
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Heres how I wired mine. The wires connected to the fuse panel were run to a distribution block and then to 3 glowshift gauges (boost, egt, and oil pressure) as they all needed switched and constant power.
I used the conveniently located holes in the fuse panel to tap into the switched and constant 12v. One side of the 5A fuse is plugged into the panel and the other side is attached to the gauge wire via a female spade connector run through the backside of the panel.
EDIT: Also note that the glowshift wiring is switched 12V = red, constant 12V = yellow, whereas the VW wiring is the opposite (on the wires behind the fuse panel of my car anyways).
I will say that I had a VERY strange electrical gremlin acting on my EGT gauge when I first hooked it up but it was the result of me trying to run an aircraft spruce probe with the glowshift gauge. As soon as I switched back to using the glowshift probe, the problem disappeared. -
#9 by Rat407 on 21 Jul, 2008 18:37
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I got it to work. Turns out the ground was not good. I took it straight to the Neg terminal on the battery and it is working. It sure does react fast too. Now to be careful. I took it up to 1200 in no time.
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#10 by Vincent Waldon on 21 Jul, 2008 20:48
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Quote from: "Rat407"
react fast too. Now to be careful. I took it up to 1200 in no time.
Yup, once you have an EGT and see how easy it is to get in the red you are soon recommending "don't leave home without it". -
#11 by saurkraut on 22 Jul, 2008 09:26
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Quote from: "Vincent Waldon"Quote from: "saurkraut"
Worst case, you can use the injection pump stop plunger wire for power as that is switched.
... although not fused... so caution is warranted !!
yah, I'm not a big fan of the using the stop solinoid either. Haven't used it my self. I think Roger Brown recomends powering his opticle tachometer drive from the stop solinoid though.
But constant power to anything but the clock kind of bugs me, and there is at least one switched 12V terminal on the back of the fuse box that is wide open for use.
That's what I'm useing to power my EGT contraptions on both of my Rabbits. Works good, lastest long time.
I haven't looked in the Bently, but I wouldn't be surprised to see the terminal labled 'accessory'.
And if you want to see a fast EGT reading, get the Aircraft Spruce thermocouple. It moves as fast as the boost gauge. And you will be surprised how high the EGT actually gets, as the slower thermocouples will never show a max temp because they are so slow.
On my '79 1.6TD, I had been running the VDO thermocouple and gauge, and hadn't seen anything much over 1,250°.
A few months ago, I swapped in the Spruce thermocouple and discovered that I was getting up to 1400° max EGT under the same conditions that the VDO thermocouple showed 1,250° and climing.
Typically I was going too fast and had to let off befor the VDO thermocouple had reached a peak temp. But the Spruce thermocouple is so fast that it shows more of a 'real time' reading.