RCU Forums - Merlin 140XBL starting issue

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Robd	06-01-2018 07:10 PM

Merlin 140XBL starting issue

Just throwing this out while we are waiting on a couple of call backs.
I have a JetsMunt Merlin 140 XBL with the JetsMunt version of the Xicoy ECU. This is the one with the 3 wire interface to the turbine.
During the start sequence the temperature reading drops from ambient to 0 as soon as the throttle stick is dropped to begin the sequence. The burner lights and fuel flows but the temp stays at 0. As a result, the start fails sometimes with a flooded engine.
I have a brand new 2S 4000 mAh 50C ECU LiPo battery and I am told the igniter voltage was raised 0.2V from standard.
Everyone I have spoken to tells me the temperature indication should start to rise from ambient as soon as the fuel ignites.
It is acting to me like a buggy version of the ECU software.
Anyone else experience this and if so how did you resolve?
Thanks
-Rob-

ira d

06-01-2018 07:16 PM

Sounds like a defective temp probe to me or a defective connection of the temp probe to ECU. Other than than that Defective ECU could be the cause.

scoeroo

06-02-2018 09:22 AM

I suggest turning on the system to pre start mode and read the TC ambient temp on the data terminal , then with a heat gun hit the thermocouple at the exhaust , if the temp rises the TC is good

Next run the stick up & down to go into start-up sequence , if the data terminal goes strait to zero instantly you can then take it that the ecu is having issues

Another check is to see if there is a high resistance crimp on the 3 wire connection cable that leads from the ecu to the turbine

FenderBean

06-12-2018 01:59 PM

Quote:

Originally Posted by ira d (Post 12437032)

Sounds like a defective temp probe to me or a defective connection of the temp probe to ECU. Other than than that Defective ECU could be the cause.

I had this on one of my turbines it was the temp prob

Robd	06-13-2018 04:47 PM

Just to close out this thread, I did hear back from Gaspar and he feels the problem is with the thermocouple. Albeit not that it is broken but rather the insulation / installation has been compromised. It does require changing out so the engine is off to be repaired.

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