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2015 WR250 ECU insight

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Recently purchased used less than 10 hours. Comp ECU installed with stock exhaust. Can't seem to get the bike to idle properly with the comp ECU. Reinstalled the stock ECU and bike idles fine. It's gutless but the bike idles fine. Here's the question... was it possible the ECU was damaged due to faulty power tuner hook up?

Tried a few different maps and made a difference with the overall engine characteristics but the bike has a hard time at idle. Also with the comp ECU the idle screw adjustment would not adjust idle up or down. With the stock box it worked as it should. Any insight on this problem is greatly appreciated.

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Any codes? Sounds like a possible problem in the ECU. I would say the pressure sensor but it doesn't make sense if the bike idles correctly with the stock ECU.

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Did you perform all of the other steps of the ECU installation?

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Air box and stop screw. Is there anything else?

5 hours ago, YZEtc said:

Did you perform all of the other steps of the ECU installation?

 

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I would bet the comp ECU wants a more free flowing exhaust.  That stock muffler is heavy and the hole at the back of it looks like it should be for a 85 mini bike.  Find someone who will let you try their 2014 + F or FX stock or aftermarket exhaust and see if it helps!  

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2 hours ago, poconovfr said:

Air box and stop screw. Is there anything else?

 

Did you remove the exhaust muffler outlet reducer (AKA pea shooter)?

Edited by YZEtc

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well that's another issue. Ran the bike with and without and it ran better with the pea shooter in...

1 hour ago, YZEtc said:

Did you remove the exhaust muffler outlet reducer (AKA pea shooter)?

 

2 hours ago, Shredjim said:

I would bet the comp ECU wants a more free flowing exhaust.  That stock muffler is heavy and the hole at the back of it looks like it should be for a 85 mini bike.  Find someone who will let you try their 2014 + F or FX stock or aftermarket exhaust and see if it helps!  

 

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Very strange

Its not possible to damage ecu by connecting power tuner incorrectly

Have you confirmed that any maps you load up have been written to the ecu by loading it back to the tuner?

Idle adjust is mechanical so ecu swap shouldnt affect it

What is the idle speed with comp ecu fitted...the tuner will tell you

There is a cat fitted at the first joint in the header (above gear lever)..this needs to come out as well

 

 

Edited by GuyGraham
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Just to make sure:

The muffler outlet reducer is the little pencil-diameter thing that is riveted into the outlet snout of the muffler, not the whole outlet snout which is held on by four bolts.

The outlet snout remains in place after you remove the little reducer by drilling out the rivets.

I couldn't imagine you wanting to keep the reducer in place.

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look in here

Don't forget the Cat in the first exhaust joint above the gear lever - it'll never run properly with that thing stuck in there

 

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On ‎6‎/‎2‎/‎2017 at 1:18 PM, GuyGraham said:

Very strange

Its not possible to damage ecu by connecting power tuner incorrectly

Have you confirmed that any maps you load up have been written to the ecu by loading it back to the tuner?

Idle adjust is mechanical so ecu swap shouldnt affect it

What is the idle speed with comp ecu fitted...the tuner will tell you

There is a cat fitted at the first joint in the header (above gear lever)..this needs to come out as well

 

 

 

16 hours ago, YZEtc said:

Just to make sure:

The muffler outlet reducer is the little pencil-diameter thing that is riveted into the outlet snout of the muffler, not the whole outlet snout which is held on by four bolts.

The outlet snout remains in place after you remove the little reducer by drilling out the rivets.

I couldn't imagine you wanting to keep the reducer in place.

The cat is not removed. let's try that. thanks

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Ok some updates.

There is no cat on the US model.

New FMF on the way.

Here's a question...there are two screws on the throttle body. One (in the front) is the throttle limit screw at WOT. The screw that gets replaced. Done.

In the back of the throttle body there is the throttle valve stop screw, which Manual says  "don't touch". Well yeah I'm that guy... On the initial set up I removed said screw like an idiot.

I do believe this would be some of my problem at idle. So does anyone have a clue what the adjustment might be? I've talked with a few dealers and it seems I have become more educated then they on this subject.

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I believe its the stop screw for when the throttle is closed, in order to kept the butterfly valve open a little bit and hence let air flow into the engine

 

attach the tuner and go into monitor mode and see what it says that the throttle opening angle is (T/P value) - when the throttle is closed it should be 0°

at full open it should be 79°

Edited by GuyGraham

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