Author Topic: Autometer EGT oddities...? (Read 4822 times)

745 turbogreasel · « **on:** April 27, 2006, 07:19:38 pm »

Autometer EGT oddities...?
I just installed my Autometer cobalt EGT guage. Sender is preturbo.
It looks sweet as I expected.
But it seems to behave a bit wierd.
After compression braking down a long offramp...
...There is a fuel cut situation, so it should just be heat of compression, and a bit of soak from the manifold. But the guage reads about 50F below ambient!!!!

Anyone else have one of these things?
Also, the guage seems set up for a dimmer on the supply side, but my 740 has the dimmer on the ground side, Wondering if somone has dealt with this. I'd call Autometer, but they are closed for the day. Darn central time!

hillfolk'r · « **Reply #1 on:** April 28, 2006, 12:39:21 am »

ive always had trouble w/ autometer egt's,,so has rabbittree,,but i got a westach from aircraft spruce and supply for about 60$, with a 4 foot probe,they got probes to 20 feeti think ,,its backlit,mounted preturbo,scale is from 0 to 1900f,and has a c scale on it too,and looks like it belongs in a plane too!!its in the trio on the right,the left one in that guage pack,,they have crazy ones,,dual scales,mount pre,and post turbo,read from 1 guage!!!aircraft stuff rocks
[/url]http://www.aircraftspruce.com/http://[img]http://img222.imageshack.us/img222/1804/hpim00787ww.jpg[/img]

jackbombay · « **Reply #2 on:** April 28, 2006, 03:53:45 am »

I have an autometer Z-seriees and it drops to about 180 F when going down long steep hills.

Did you cut the wires that go from the probe to the gauge? That will throw off the reading, the resistance of the wire is specific and is part of the gauge calibration.

But I have also had to return 2 autometer boost gauges in the last 6 months for various problems, i am not all that impressed with their quality, you could have a bunk gauge...

RabbitGTDguy · « **Reply #3 on:** April 28, 2006, 05:55:31 am »

I have the autometer phantom series pyrometer (EGT) which uses a standard K thermocouple. Have never had problems with it dropping temps like you mentioned. I directions are very specific about grounds and even talks about the probe wires themselves "grounding out", touching persay as well as interference too. Might want to look into it. I have the PDF version of the direction if you want them. They are also able to be downloaded from autometers site..

Joe

QuickTD · « **Reply #4 on:** April 28, 2006, 05:28:15 pm »

Be careful when grounding an autometer EGT guage. Autometer EGT guages are an electrically powered unit with an amplifier. If the probe ground and the guage ground are at different potentials you will see substantial errors. The best way to eliminate any ground differentials (and the associated temperature errors) is to run the guage electrical ground to the engine block so that it is at the same potential as the probe.

An alternative would be to make sure that the body and engine are at the same ground potential by cleaning and tightening the body/engine ground cables. Then run the guage ground to a good solid hunk of metal on the body. Avoid tapping into ground wires shared by other accessories, they may be running a few millivolts above ground.

745 turbogreasel · « **Reply #5 on:** April 28, 2006, 07:00:03 pm »

The kit was new in the box, 10' probe is new and unmolested. THe ground is on its own wire to the steering collumn support structure(beefiest part behind the firewall. There is only one ground wire from the unit, I have the directions. I'm a bit dissapointed to be having this issue, the dial looks nice, and response time is good.

Another thing I have noticed is if EGT is over about 150 when I shut down, I usualy have to cycle the key multiple times to get the needle back to 0 in the morning.

I'll clean the ground cables, but they are fresh and beefy, so I don't have great hope.

Fresh injectors and HG with Raceware studs (Randy dold me torque to 50) seems to have got me from 72 to 77+ in OD on the grade by my house :lol:
Boost seems good, but I think my turbo may leak oil internaly, idle fumes are a bit unpleasant. I'd like to do a test without swapping turbos, but haven't figured it out yet.

I'm off to excercise the shop vac a bit more, its amazing how much crap can pile up in a car you arent driving!!!!

hillfolk'r · « **Reply #6 on:** April 28, 2006, 07:33:04 pm »

my "crappy lil egt guage",even unamplified,std k type thermocouple,,starts to read like 3 seconds after startup,and goes to200-250 or so,,,they have different thermocouples in different thread patterns,not just the old 1/8 pipe thread, ihad one that was 3/8-24 thread,,check out the aircraft spruce site!!!

jackbombay · « **Reply #7 on:** April 28, 2006, 07:59:32 pm »

Quote from: 745 turbogreasel

There is only one ground wire from the unit,

Mine is the same way, I think that Quick TD meant that the probe itself grounds on/to the exhaust mani so you shuld run the ground inside the car through the firewall and ground it to the engine.

Autometer was easy to deal with as far as getting a replacement boost gauge for the bunk one I got from them and the one that broke after 4 months.

QuickTD · « **Reply #8 on:** April 28, 2006, 09:14:05 pm »

Quote

I think that Quick TD meant that the probe itself grounds on/to the exhaust mani so you shuld run the ground inside the car through the firewall and ground it to the engine.

Correct. My autometer guage is very fussy about grounding, understandably so, type k thermocouples operate in the millivolt range.

A non-electronic direct reading guage like some isspro's and hillfolk'r's aircraft spruce unit are immune to this type of trouble because they drive the meter movement directly from the thermocouple voltage, 2 wires only, no amplifier, no seperate ground wire for the guage and few problems. The amplified units like the autometer offer marginally better response though, they also match the rest of my guages, purchased earlier...

lesharoturbo · « **Reply #9 on:** April 28, 2006, 09:52:37 pm »

I have an ISSPRO EGT and I love it. It seems to react very quickly at startup and when speeding up or slowing down. Good money spent. No ground wire thermocouple only.

Bernie

hillfolk'r · « **Reply #10 on:** April 29, 2006, 01:10:37 am »

on mine you also have to "adjust" for ambient temp, which the "base" is 75 deg.f ,so if its 30 deg.f outside,you have to subtract 45 deg.from the guage,not a big deal to me ,all of these guages are like this,they usually dont tell you this part,just a point to keep in mind. :idea:oh,and ihad this on my 1.6,post turbo,and iwasnt impressed with the response,now that ive put itpre turbo,it reads so much quicker,like i can see little throttle increments at speed(hiway,etc) increase the temp almost instantly

Caddy-Daddy · « **Reply #11 on:** April 30, 2006, 05:24:29 am »

Here are mine: Vivid SLM (smoke lens meter) EGT and Boost.

Just a K type thermocouple works like a charm.