EGT does not work, replaced all!!
 

I had one EGT gauge that did not work when I bought the boat. I relaced the sensor (Gaffrig), replaced the gauge-Gaffrig double indicator), now replaced the wiring.... I have replaced everything and it still does not work. The gauge is proven good. It was originally installed by Arizona Speed.........Any ideas?????

Did you try starting the engine:o :o :D :D Sorry couldn't resist:rolleyes:
Seriously though , you replaced the gauge,thermocouple and wiring. do you need 12v to the guage?
I know the thermocoupler produces a miniscule amount of voltage to operate the guage but dont know if you still need a 12v source.

:eek: Cute....really cute!!:D The gauge requires 12v only for the lights, not used for the gauge needles.....I am mystified!!!:confused:

did you try connecting the bad guage to the good circuit? The one that works. If it does operate, is there a spot by the thermocouple where the wire is spliced. I mean a plug or something. You could put the gauge there and see if you get a response. You know substitute untill you find the broken link in the chain.
Thermocouples use a specific type of wire for each type of thermocouple, "k", "j" types. And the wire is polerized. You cant just hook up the leads, they are color coded for a reason.. If you have volt meter, and there is a connector by the engine, you can check for a voltage at that point, then start the motor and see if it increases!!

Hope this helps, good luck.

Dick

Mr Gadgets,.... I did all that replacement & substitution thing. swapped sides of the gauge & it works..... I cannot however check for thermocouple voltages because they only use milli-volts ofr less. A multimeter is not sensitive enough to read them.
All parts are Gaffrig & new. Wiring polarity was observed. Continuity is good but still no reading. The thermocouple leads are fairly short and the gauge/coupler indicate from 600- 1600 degrees. Pretty warm to be sticking your arms into!!:D

If the sensor is mounted in the manifold at the #2 cylinder, if that cylinder was "dead", would the sensor not read at all??? I would suspect that at WOT, even with a dead cylinder (NOT that it is) it would indicate SOME heat....but nothing!!! Over $200.00 and no fix yet. :(

thermocouple output
 

You said the output of the thermocouple was too little to be read by your meter. I think it is also too little volts to drive their gage without 12 volts to work their signal conditioning. Try emailing their tech department to check wiring and to find out how they suggest to diagnose the proublems. The tech help email is [email protected]

some of the cheaper EGT's use the DC milivolts supplied by the thermocouple. The problem with these is a needle that is not steady. The higher $ units use 12V DC to power the meter. The EGT for my diesel truck is this type.

I would not call $128.00 for a Gaffrig gauge cheap, and Gaffrig sensor was $48.00 and the Gaffrig wire (25 feet) was another $50.00. There instruction sheet says specifically that 12v applied to the meter will cause severe damage. Besides, it is a dual gauge, reading EGT for two engines & one works fine and is steady as a rock. When the engine leads are switched at the gauge, it reads fine on the other side!! :eek: I would say that if these are "cheap" parts, then Gaffrig needs to lower the price or everyone here better quit depending on them for other function monitoring as well. Please re-read the thread & it is said that the gauge works on one engine and not the other & all components were replaced.
I was sure that someone here had experienced a similar problem before and could offer some advise.:confused:

Blown forumula,

"swapped sides of the gauge & it works..... "
You put the good gauge on the bad circuit and it worked?? Did you put the bad gauge on the good circuit, did it work?

I have a sheet somewhere that gives the voltage reading at a certain temp for "K" type thermocouples. I know it is in millivolts, but a good quality digital meter should give you an indication. I am looking at the idea of looking at the circuit in place that is not working. To check the wiring from the gauge back. If you use the good gauge as a volt meter to check the wiring of the bad circuit, does it work? If you swap the wiring from one gauge to the next does the problem switch? If there isnt a way to check the thermocouple in the engine bay, connect the gauge or volt meter directly to the thermocoupl, then you will could remove the thermocouple and put it in the other engine.
I use a Fluke meter with two inputs to check my temps. I also have used a volt meter, but I dont remmber what values I saw on the meter. But I have removed the thermocouple and applied heat from a propane torch to excite the thermocouple to check to see if I get any output from it.
If you subed everything, then the problem should have moved at one point, if you have a bad component. If you have a dead cylinder, it would read room temp or ambient temp. You wont see that with your gafrig gauge, but a volt meter will show some indication. Remove the wire from the good gauge and read it with a 3 digit voltmeter, then do the same with the other one.. see if they are close.. I will look for the chart for temp/volt on thermocouples when I get back into town at the end of the week..

good luck

Dick

Dick, Yes I swapped the good gauge to the bad circuit sensor & wiring and still no reading. moved working good sensor & wiring to the "dead" side and reads fine. How can two sensors &/or two wire sets be bad???? My next trick may be to swap sensors in the engines left to right!! what a bummer!!:)

The EGT for my truck (DIESEL) cost $185 and it is a single. It uses 12 volts and is VERY steady and very accurate. The duel one that I bought for the boat cost $135 and it is a joke. I used the K type thermocouples only with my FLUKE digital meter.

Let me get this straight.. you swapped good gauge to bad side, no reading.. ok.. problem is still on bad side.
Moved working good sensor & wiring to the "dead" side and reads fine. Does this mean you took wire from good side and put it on the bad gauge? If so that tells me both your gauges are good.
Or did you take the wire and sensor from the bad side to a known good gauge?
How many wires go to the back of each gauge? Two from sensor, one from 12v for light, and ground?
Try switching sensors and see what happens.. Does the sensor have a 25' lead on it or is there a connector in line with it by the thermocouple??

It would be nice to have a known good gauge that you could move around to check at different points, like a volt meter. That way you can see a go/no go situation..

Tinkerboater,
are both gauges you are speaking of using an exposed tip type of thermocouple? The exposed tip will react much quicker.. just curious.. What brand of gauges are you using anyway..


Dick

Mr gadgets,
Yes, you are correct in everything you said. The bad side has never indicated on a known good gauge, then I replaced the sensor - no change... then I changed the wire ( a 25' Gaffrig wire). There are 2 bolt & nut connectors on leads of cable & sensor (again-Gaffrig sensor). still nothing on any good gauge!!! I am really exasperated :( especially after melting the other engines piston..... this new sensor is somewhat longer than the original also. thanks!!

ok, you have a sensor, then the connection to the 25' lead, with two bolts and nuts? You replaced the gauge with a known good one, and it didnt work. Then you changed the thermocouple, still NG. Then you replaced the wire (25'), still no good.. Ok, take the good gauge, old wire (if it isnt still in the boat) and old sensor. Hook it up and put a match to the end of the themocouple.. You should see a reading. If not, try another sensor, if ng, try the other (new) wire. If the wire seems to be good and the sensor seems good, use a match to heat the thermocouple.. That way you eliminate the engine as a problem..
Now make sure you are safe with the open flame.. you know..gas fumes..etc.

I would also try to connect the thermocouple without the 25' wire.. see if it works then. That is if hooking it up that way is possible..

Dick

I would try MRG.'s idea of heating up the themocouple with a match & take the engine out of it. Sure hope that the engine is OK. I know I ran with a dead cylinder once & only way I knew it was that motor was running with more boost when I was crusing than before.

Dick--- The EGT that I bought for the boat is a WESTACH. It is junk -the needles bounce when you hit a wave. I used the thermocouples along with my FLUKE meter. Works great and reads out in digital with memory recall. The one for the truck is a VDO and the needle doesn't move when you hit a bump. I thought it was bad when I started the truck since it was reading 250 DEG,s on the peg ( lowest reading is 250 ) I didn't realize that a diesel idles at that temp. My boat idles at 750-850

i'm sure everyone knows this....how a TC works is to dissimilar metals touching ALWAYS produce a voltage...as temperature changes so does the resistance. hummmm hence corrosion. so they need no outside power. your TC lead (wring to the dash) MUST match the TC installed...i have had very little luck, long term, with TC's sold to the general public. i now use VERY high quality ones...which i can also swap out in less than 15 seconds if one fails.

placement is very critical as well!!!!

audacity, all components are by the same maufacturer- Gaffrig.

Mr. Gadgets, I am going to try an industrial heat gun on the thermocoupler to see what happens. You cannot connect the thermocouple directly to the gauge however (dang it!!) That nut & bolt thing is the problem, they are VERY small machine bolt & nut. :)

Tinkerboater,
I see what you mean now.. cheap meters dont like bumps..!! :D

blown formula,

I found the chart for K type TC's.. at 500 degrees, you should see 10.56 mv.. or .01056v. At 1000degrees 22.250mv not much change and definitely need a good digital volt meter. But with a go/nogo you test you should see some change from room temp to high temp.
The exposed tip type TC's are the fastest reacting, because they are exposed, but they dont last long.. If there is a case around the TC it will take a while for it to warm up.. The match or propane torch works wonders, but you have to be careful not to melt the insulation on the wire..
At least you will take the motor out of the equation. Good luck and let me know how it works.

Dick

I spoke to the Livorsi Tech line today. They said their TC will output as much as 3-4 volts & can be read on a multimeter!! That's a real surprise after reading other threads about T.C.'s & EGT's. He said to do the "DUMB" test with a lighter or heat gun. I did not get a chance last weekend .....so I will do it next fri or sat.
Tinkerboater.... Gaffrig EGT gauges DO NOT BOUNCE in rough water! That's a fact!:D (at least the dual gauge does not). :)

yeah but my eyes do!!!

Now THAT is a true statement!!:D

YEA but my DIGITAL FLUKE meter reads out in big numbers so you know exactly how hot it is and you can record how hot it got.

:D :D

Well, I finally found out why the EGT didn't work. I was hoping it was a bad sensor (new) but found the #2 cylinder dead.
After "it's final...Meltdown" earlier on the port engine I was hoping for better news but not so......I'll pull the starboard engine in a couple of weeks...... but winter is arriving early here so I pulled the boat to winterize the port engine, hooked up the hose to the low water pickup and started the engine......2-3 minutes later I smelled hot rubber !!! found no water was being pumped to the engine!! So I now have a bad impellor also on the "new" engine!! I just can't win this summer.
I hope never to repeat this summer again:mad: :eek: :( :) !!

blown formula,

Man that sucks!!!! :( :( I am sorry to hear about your delima. It seeems like it is time to step back and forget for a couple of weeks and then hit it again. Not much consolation, but when my stuff breaks, I go play with my grand daughters.. That puts things in perspective. It will come together, just keep at it. I spent two summers like yours and it will come and go. Just dont let it get you down. I did manage to run 50+ hrs this year, but the drive is in need of repair again. So I know where you are coming from.. but I am determined to get this right.. what ever it takes. The reason?? IT's a Hobby!!

good luck

Dick

Mr Gadgets:
I can tolerate it because I have a pontoon boat for lazy pleasures with the wife and family. And the fishing boat for those early morning and afternoon outing for solitude. The "big" boat sometimes sits on the lift and we defer to the pontoon! Crazy, isn't it? With the troubles we have had this summer, I suppose we do not have the confidence we had with the other Formula.....yet. But it will come. Next spring, both engines will be new and a few other things will be fixed also. Clean slate!:D
Thanks for the kind words. Have a good fall and winter.:) I will!