ZU-DVE EGT Temp

[gertcoetzee]

After buying (yet) another new EGT probe and installing it, I get a 100C difference between the two EGTs,with the one being above 680C. Initially I thought it is because the probe is too close to the metal of the exhaust, since I had that before with a ridiculously high temperature, but even putting spacers in does not change this difference. I doubt that the reading is accurate, since I have been flying for hours with this discrepancy, with no problems, and the water temperature remains normal.

Any advice?
Gert

[Duck Rogers]

Gert...I'm going to assume you replaced the high reading probe with another one. Is that correct? And the gauge is still reading high?
Then either you really have high combustion temperature or I would suspect the gauge. Too be sure, check your plugs. They are the only true indication of what really is happening in that combustion chamber. If the plugs don't confirm the high EGT reading by showing as overheated, then it's not.
Another thing you can try is to swop the probes around onto the different gauges. Example: probe 1 = gauge 1 and probe 2 = gauge 2. Now put probe 1 onto gauge 2 and vice versa. If the "high reading" gauge is still high, then that gauge is faulty and if the "low reading" gauge goes high, then the problem is probably the probe or really high combustion temperature BUT you must confirm this by checking the state of the spark plugs. Spark plugs don't lie.

You can also swop the probes around at the exhaust side to test them.

If you have a joint in the probe wire leading to the gauge or have some sort of extension added to it to get it to the gauge, then that may also affect the reading, but I doubt if this will amount to 100ºC difference, so I'm not going to try and explain about "cold" junctions and "hot" junctions now. Just perform the basic troubleshooting first.

[Miskiet]

Gert,

I suspect someone fiddled with your instrument's set-up. You get two types of egt probes (J-type and K-type). You need to tell the instrument which one's you are using. Mine from MGL is K-type.

I had a friend who wouldn't leave the runway cause he thought engine failure was imminent with the high temps. Surprise when we corrected the type setting on the instrument the temps was normal.

Just one thing to check before you spend thousands!

[gertcoetzee]

I'm going to assume you replaced the high reading probe with another one. Is that correct?

The fuel gauge stopped working, ordered a new one, the new one gives the high readings

Then either you really have high combustion temperature or I would suspect the gauge.

But the water temperature is fine, I suspect the gauge, and remember I have a SKUDUDD digital system - could be that as well (remember my troubles with ref counter, fuel gauge)

Too be sure, check your plugs.

Please do - these are four plugs - don't ask me which came from which, but they all look the same to me, ie point bits at the one side and hooky bit on the other side:

Another thing you can try is to swop the probes around onto the different gauges.

Will do that on Wednesday

If you have a joint in the probe wire leading to the gauge or have some sort of extension added to it to get it to the gauge, then that may also affect the reading, but I doubt if this will amount to 100ºC difference, so I'm not going to try and explain about "cold" junctions and "hot" junctions now.

I have a joint, since the probe's "gauge end" does not fit in the Skydat box.

I suspect someone fiddled with your instrument's set-up. You get two types of egt probes (J-type and K-type). You need to tell the instrument which one's you are using. Mine from MGL is K-type

.

No, noone fiddled. I have no idea which type Solowings supplied.

I had a friend who wouldn't leave the runway cause he thought engine failure was imminent with the high temps.

I've been told that once EGT temps get high, the damage is done. The important temp is the water temp. Comments?

[Duck Rogers]

Gert...those plugs look just fine to me. The hooky bits' colours are good. No overheating there, so we're back to the gauges and probes.

There are indeed different types of probes. Generally the J-type is for CHT and the K-type for EGT. The main difference is in the temperature operating range. Theoretically the J-type is supposed to be good up to 750ºC and the K-type up to 1200ºC. If you're reading above 680ºC and mistakenly have a J-type probe, then I would reckon that probe is as near to being destroyed as can be because I've melted one at about 600ºC before. I would guess that Solowings will know that they're supposed to be installing K-types.

I've been told that once EGT temps get high, the damage is done.

Not if you catch it in time and take corrective action.
As far as the water temp is concerned...by the time that it shows a high reading, the pistons are probably cooked. The CHT (cylinder head temp) and water temp sensor will lag behind the EGT due to the mass of metal in the cylinder head that has to be heated whereas the EGT sensor picks up the changes immediately. In my opinion the EGT is a far more important indication.

The electronic gauges can normally be calibrated for the thermocouple type used (in this case it should be calibrated for K-type, providing of course you have K-types installed) in order to show the correct reading.

We can discuss the joints in the probe wires after you have done the gauge swopping test. :D

[gertcoetzee]

The probes are the Falcon Gauge Model No EP-002 Wiltrad, Inc supplied by Solowings.

We can discuss the joints

It's a free country we should be able to smoke what we want, when we want, where we want.

[Duck Rogers]

:D :D :D

[Slow_Poke]

have the same problem! about a month ago i replaced an EGT Probe (suplied by MGL Avionics ) It was the PTO side and since then constantly strugling to get it right (higher EGT temp on PTO Side)! changed the "order of the probes - to no avail. plugs also look good. if you figure out something, please let me know.

[gertcoetzee]

Short and long of this (I hope) is that I was supplied with the wrong probe. Received a new one today, and will try it out asap.

[Robin Hood]

I battled for a year with the probes on my GX1. Bought one new probe after the other. I was always told that the connections at the sender unit were the problem but did not really attend to that. Then I got can of Spanjaard Electroclean from someone and cleaned all the connection points. My EGTs have subsequenly worked PERFECTLY.

Indeed my fuel level guage was giving erratic readings. That is now 100%. My rpm guage had stopped working and I had replaced that with a Tiny Tac. That has started working again.

Worth a try I suppose?

[Robin Hood]

I battled for a year with the probes on my GX1. Bought one new probe after the other. I was always told that the connections at the sender unit were the problem but did not really attend to that. Then I got can of Spanjaard Electroclean from someone and cleaned all the connection points. My EGTs have subsequenly worked PERFECTLY.

Indeed my fuel level guage was giving erratic readings. That is now 100%. My rpm guage had stopped working and I had replaced that with a Tiny Tac. That has started working again.

Worth a try I suppose?

[gertcoetzee]

Then I got can of Spanjaard Electroclean from someone

Is this the generic name for Spanish Fly, 'cause I might still have some of that around?