Problem with The Injector (KTM 450 EXC)

[Mohamed Aziz]

Hello,

I am Mohamed Aziz, the head of engine team in Cairo University Racing Team.

The engine we use is a single cylinder KTM 450 EXC engine. Our controller is MegaSquirt 3X with V3.57 board.

We were testing the car till it suddenly stopped. I tried to increase the amount of fuel injected till the engine started once or twice but the amount of fuel was too high compared to that values with which the engine ran before.

So, I disassembled the injector and made sure that every part is fine. This means that no hoses are clogged or bent in a way that chokes the flow.

Then, I assembled it again and the engine was fine for about one minute before it went crazy again and stopped.

I used the testing mode in TunerStudio program and it was obvious that the flow rate of the injector is lower than normal (I tested it before) and it is not a steady flow.

You can watch the test here: https://www.youtube.com/watch?v=rVEHO6WMZ0o

[Swiftus]

Looks clogged. Put in a new fuel filter, flush the fuel system and then put on a new injector (or take that one to get cleaned).

[harshitr2]

Did you check fuel pressure? If the injector isn't clogged, then it must be fuel pressure.
Also, have a look at the KTM inline fuel filter.

Harshit

[Ahmad Rezq]

We've checked the pump and the injector (Cleaned them and replace the filter).
the injector worked very well and the engine was fine in running. but again the same issue had happened :
- the engine increases the rpm rapidly maybe to 9000 rpm without throttle opening.
- in some cases the engine rpm rapidly changes from 7000 to 9000 and back to 7000 and so on.

i think that the injector is fine because it works very well and sometimes it works like in the video posted (i don't know) can someone confirm?

I'am not related to the engine or electric work ?
but i think (maybe) it's something related to the wiring, maybe ECU or sensors? (any help)

[Swiftus]

Likely a vacuum leak.

[Ahmad Rezq]

Swiftus,
we have checked the intake system and found no vacuum leak. this leaded us to re-check the injector again (although we have cleaned it and replaced the filter) the injector seemed to be clogged again.

harshitr2
the fuel pressure from the pump is 2.8 bar

[harshitr2]

@Ahmad
Was the issue resolved? I'd like to know what went wrong there.

Harshit

[Mohamed Aziz]

We purchased a new injector and it was very good. The car was driven on track in FS UK and FSG and there were no problems with the engine because of the injector.

Unfortunately, the new injector behaved the same way as the old injector one month ago. The engine can not be accelerated and it is down if the throttle is abruptly opened.

Is it possible that the injector get clogged in just two months of operation?! Anyone had the same problem with Keihin injectors?

Note:
I have measured the flow rates of the two injectors for different rpms and PWs. Both injectors have nearly the same flow rate (about 280 ccm).