schroedm

My Feedback: (1)

Guys,

Thought I'd garner opinion regarding a start problem I continue to have with a new P160SX.

Basically, it has real trouble starting on the kero. There isn't enough getting to the turbine. The solenoid clicks away as it should but if I disconnect the kero start tube from the turbine then there is virtually nothing coming through. The start fails with ignition time out but if I just keep trying it'll start on the 3rd or 4th attempt. Once over to the main fuel feed the turbine runs a treat.

I thought it may have been a faulty or blocked solenoid so fitted a new one but it does the same. Filter is spotless too.

If I use the GSU to test the 'burner' valve then it works fine and the kero drips through as it should.

Is this a case of upping the pump voltage somehow for the starts?? I'm not 100% but I think I saw Pv on the GSU of around 0.2-0.3 during the start sequence. Does that sound right??

Any help would be appreciated!!

Thanks
Mark

Dave Wilshere

Mark

Stiff pump. I have seen a couple recently than needed a higher voltage to kick the pump going, yes increase the start voltage, maybe to 0.4v.
You can normally feel light warmth and see the burner glowing if you hold your hand across the tube or look from a safe distance. This tells you its no fuel.

Dave

FILE IFR

Mark,

Just a thought that comes to mind...
Before I ever started one of my engines, I discovered I installed the solenoid backwards, I proptly fixed it before it's very first run.

JetCat says it makes a difference in the orientation of the solenoid.... just a thought and a thing to double check on yours.

Good luck to find the problem if that's not it.

Harley Condra

My Feedback: (4)

Mark,
I too had the same problem when I installed my JettCat Titan in my new KingCat...just as Mike stated, I had installed my kero-start solenoid valve backwards.
Turning it around solved the problem and no other changes were required.

rcand

common problem. make sure your fuel filters are not clooged first. Then start increasing UACEL1.

schroedm

My Feedback: (1)

Thanks guys. Solenoid is correct way around.

I will look to increase the pump voltage to 04.-0.5v.

Rgds,
Mark

blackcat

0.4 to 0.5 is a high start value, so expect some flames as the engine transitions to normal fuel. remember that the kero start is only pre-heating the combustion chamber, imagine a gas start engine with a pump start voltage that high, its a bar-b-que ! i would encourage you to (if th engine is in the airframe ) make a closed loop in the fuel system, by putting the line that enters the engine back into the fill valve and hold the pump test button on for a total of 40 - 60 minutes, then check / adjust the pumps start voltage, and / or temporarly install an on/off tap after solenoid and before the engine, and only allow a dribble of fuel in on start. be careful of allowing 0.5 worth of fuel in at start-up, especially if its in the airframe. you may not burn it, but the pipe will certainly not appreciate it

Dave Wilshere

Mark

Yep, you can check flow in the test. The latest batch of pumps seem to need a higher figure, maybe after some running it will reduce again, but for now fuel needs to be flowing. Some pumps also "stick" between gear teeth and need a higher voltage to kick them loose

Dave

schroedm

My Feedback: (1)

Guys, if I use the GSU to test the kerostartvalve then a healthy trickle of fuel flows. Would thisindicate the pump is ok at low voltage or does the pump push more at this point than during the start up?

Last night I was using the kerostartvalve test with the lines still hooked to the turbine to try and prime things. Worked ok but I knew if I overdid things it would get lively!

Btw, where in that JC menu structure do I up the pump start voltage if I need to??

Cheers
Mark

schroedm

My Feedback: (1)

Double post

Dave Wilshere

Mark

No, same voltage so maybe pump is free already?

Hold Limits and plus key

Dave

Carsten Groen

Mark,
funny, but I discovered the same on a friends new P160SX a week ago!
It was set at Uacclr1 at 0.200 volt, we increased it to 0.275 and it would start fine. After a few flights we put it down again to 0.225V, works perfect.
Maybe connecting a 1.5V battery to the pump for 30 minutes (pumping fuel!) would help...
Uacclr1 can be reached in different ways, but "Limits" together with "+" is one of them

Roger M

Mark,

I've recently had the same problem with a new 120SX and has been said it needs a higher pump voltage (unaccel1). I disconnected the kero and main lines from the engine and then tried a start, increasing the voltage until fuel came out of the kero line. You have to set the voltage in unaccel 1 before each attempt. I finished up with a value of 0.40v, although the value as delivered was 0.25v. It now starts without any problems and doesn't wet start, but as soon as it shows signs of it I'll reduce the voltage.

Roger

schroedm

My Feedback: (1)

Thanks all. Good to hear this isn't too isolated an issue!

Looking up the tailpipe I can see the element glowing and flickers of flame etc but just not quite enough for it to start the start sequence.

I think I'll go with a combination of running the pump for 30mins (although it probably has this in flight time by now so the pump has been running for a while in flight) and then upping the uaccl1 voltage and running through the start sequence with the kerostart tube disconnected until I see a better flow of fuel.

Not having had to tweak values before as all my turbines have run fine from the box, can someone confirm the comment "You have to set the voltage in unaccel 1 before each attempt." - surely I set the value in the GSU/ECU and that's it for all future starts?

Rgds,
Mark

Carsten Groen

Yes, set the voltage one time only, it remembers the setting

Roger M

Mark,

Sorry for the confusing statement, I meant that you can't change the value once the start sequence is underway.

Roger

Vincent

My Feedback: (61)

Mark,
Hold the limits and plus button down, the Uacc page will come up. It will probably be set at 200. Bump it up about two clicks to 250-275. Try a start and see what she does, this is not a big deal. You can always go down a bit if there is too much flame during spool up. Once the pump gets worn in you can re- adjust.
Vin...

rctech2k7

My Feedback: (1)

On your conducted test, it indicates that pump and valves are working fine. IMO also most probable cause is pump voltage... Every motor has high starting current due to inertia and transient… When voltage is very low caused by required low rpm (required fuel flow rate on ignition) most likely for long loaded fuel line requires a little increase in power.

Another probable cause since it’s new is pump motor. Brush and bushing are still tight. Since startup voltage is very low, just impending, slightly increase in voltage will solve the problem then after certain runtime restore the original voltage settings to prevent high starting temp. Otherwise, let the pump run for a few moment until it start easily.

Hope would help.

John Casey

My Feedback: (4)

Share the pain........Let us know what fixes it....

rctech2k7......that last post is very true......
a new uncycled out of the box ecu battery lacking some poop under
all that load... starter going...igniter lighting....
new pump trying to turn over ....the ecu trying to maintain all that may
have the voltage but what about the amps to push all that .....at one time?
Breaking in the pump, which is a good thing to do on any "new" engine and upping
the voltage may be masking the true issue.

What Ecu battery and voltage are you using?
Nicad
Nimh
Lipo

BUT WAIT I re-read the post.... you wrote:
"The solenoid clicks away as it should but if I disconnect the kero start tube from the turbine then there is virtually nothing coming through."

The kerosene solenoid is ethier normally fully open or closed to prevent gravity feed fuel flow to the engine....only propane solenoids click.

why is the kero solenoid clicking?????????? and No fuel dripping? is there a setting for that like on the propane version?
should fuel drip if the soleniod was taken out of the loop?

Is there a propane solenoid port on the ecu .......it could be plugged into ???

( don't have the manuals for that ecu, I'll go get educated, off to Jetcat)

back... from jetcat... Ok..... two kero solenoids.....getting powered....

(Note: V6.0I or newer ECUs default to .....LiPoly battery type.)
.... this should be checked.

Even if the setting has been reset for...... nicads.
I had to cycle those NIB jetcat red-cased ecu nicad batteries 4 or
5 times to get them up to doing the start job on any turbine.
Let alone a kero start model.

Love troubleshooting stuff... still....Let us know what fixes it....

schroedm

My Feedback: (1)

airkiller,

Thanks for trying to help. If you read my posts you'll see that the turbine is setup correctly and runs absolutely fine once it starts so there are no fundamental issues with batteries, solenoids being plugged in the wrong port etc.

All Jetcats I've ever have owned 'click' the start valve on-off-on-off during the start sequence.

The cause is 99.9% simply a tighter valve not turning fast enough to push the kero through. I've upped the start pump voltage to 2.75v from 2v so I'll try a start and report back.

EDIT: I mean 0.275 from 0.200

Rgds,
Mark

Mylo

Mark,

I had a similar problem with my brand new P120SX just last weekend, where I had many failed starts (ignition timeouts) before the turbine finally started. I managed to start it for the second time, but once again only after many failed starts. The pump start voltage U-accelr1 was increased at increments of 0.025V and had reached 0.35V before the turbine started.

As many have already suggested, both fuel lines were disconnected from the turbine and the pump was run. This is quite easy to do if you wish to run the pump for a few minutes, simply go to Menu=>Test Functions=>Purge Fuel System and hold the Change Item button. I found the fuel to be flowing without any difficulty.

Another attempt was made and once again it failed (ignition timeout), a further 8 attempts were made before it ignited and ran for the third time. The pump start voltage was now at 0.4V and when it switched over to fuel valve … too much fuel! At this stage, I was certain it was not the fuel pump.

On all attempts, I ensured there was sufficient power in the ECU battery (LiMn 3600MAh). I also checked the filter and the hopper tank and both were clean. The burner was glowing well, both solenoids were working and installed correctly etc. Also, the turbine ran fine once it started.

After several more hours of troubleshooting and with the assistance of INTAIRCO and 2 experienced jet flyers (Blackcat & Highflyer) we eventually found the cause of the problem. Fortunately, a bubble was in the burner fuel line and during another failed start-up, what we observed was an inadequate amount fuel flowing into the turbine; the bubble had moved downstream slowly but then commenced to move back upstream after the failed start. We determined that there must be a partial blockage inside the turbine; somewhere inside the turbine, between the 3mm festo fitting and the burner. There was insufficient fuel reaching the burner to allow for ignition.

A friend applied a vacuum to the line and “pop” it was cleared. We don’t know what came out, but I suspect some residual braze inside the burner feed tube or swarf from the burner solenoid valve moving downstream and lodging itself inside the turbine.

The pump start voltage was then lowered back to the default setting of 0.2V and the turbine started without a problem. Several subsequent starts have since been made and the turbine starts and runs flawlessly.

Can I suggest that you take a very close look at the fuel flowing into the burner valve with the fuel line connected to the turbine? Do this by going into Menu=>Test Functions=>Burner Valve Test.

Also please be aware of the following test functions:-

[ul][*] Burner Valve Test- Runs the fuel pump and opens the burner valve (clicking). [*] Fuel Valve Test - Opens the fuel valve only (does not run the fuel pump).[*] Purge Fuel System - Runs the fuel pump and opens the fuel valve.
[/ul]
Perhaps you have the same problem. If not, then I hope the above has been of some help to you.

Good luck with it.

George

schroedm

My Feedback: (1)

Hi George,

Thanks for the response - very informative and sounds identical to my issue. Mine finally starts after maybe 4 or 5 attempts.

Can you explain your comment

"A friend applied a vacuum to the line and “pop” it was cleared. We don’t know what came out, but I suspect some residual braze inside the burner feed tube or swarf from the burner solenoid valve moving downstream and lodging itself inside the turbine. "

What did you use as the 'vacuum'? And was there an audible 'pop'!? Also, I take it you mean you fitted a 3mm line to the turbine festo fitting and applied the vacuum to that line to remove a blockage from inside the turbine?

I will certainly bear this in mind but I think my issue is fuel pump voltage as disconnecting the 3mm line from the turbine and doing a start sequence shows little to no fuel dripping out of the line - this would mean little to no fuel is even reaching the burner (although a blcokage would compound the issue!)

Rgds,
Mark

Mylo

Hi Mark,

Use a handheld pump or syringe. Your understanding of attachment to the turbine is correct.

A pump start voltage of 2V is excessive. The Jetcat Instruction Manual states normal values are between 0.10-0.325V.

I’m of the opinion that you have a fuel restriction to the burner valve as it runs normally following a successful start. Have you carried out a burner valve test downstream of the solenoid valve? If so, what was the lowest pump start voltage obtained when the fuel commenced to dribble to atmosphere?

If you have another Jetcat then consider replacing the fuel pump and if that doesn’t work change the burner solenoid valve as well.

Regards,
George

Vincent

My Feedback: (61)

George,
I have been running jetcat kero start for over 3years now on all of my motors. A .200 setting is the typical setup direct from jetcat. I have NEVER seen a normal starting motor work below that setting consistantly.

Mark,
Just another thought for you.Please make sure you have the kero start valve plugged into the correct outlet on the ecu. The motor will start if its plugged into the speed sensor port but it will be erractic and time out alot.
Vin...

Carsten Groen

I have/had several running with a Uacclr1 below 0.2, so not uncommon.
Two P60SE, both running at 0.125 (consistantly for more than 100 starts), and a P80SE that runs at 0.150
Most of my P160SX are however at 0.175/0.200
It is always a good idea to run the "drip test" in the JetCat manual!