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ECU Issues

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Wasn't sure where to post this but figured this would do...

 

Engine runs fine with current ECU. No unusual burps, farts, smells, runs perfect.

 

I have a spare one here (also a stock ECU) which has known "running" issues - mechanic's words not mine, which I'm trying to pinpoint as I have a couple of plans for it if it's serviceable.

 

Starts fine, doesn't misfire or anything. I've checked for error codes and am getting none, so as far as the engine is concerned everything is as it should be. It appears to be running extremely rich though. It's not blowing smoke but the exhaust smells badly of fuel and the engine is running very cold - about 20 degrees colder in any given situation than the stock ECU. Removing intake and exhaust restrictions doesn't seem to help at all (doing the same thing would make the other ECU very lean) so it's obviously running very fat for some reason.

 

 

I need to know if this particular ECU is stuffed or is just running a rich tune (maybe came out of a worked engine, unknown history). If I could get it re-mapped that would be awesome but I don't want to waste money on it if that won't solve anything.

 

 

Anyone got any suggestions/advice? Ideally I'd just buy another one and be done with it but they're pretty hard to come by.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Bike but the principles are the same.

 

Given that everything is fine with the other ECU installed it can't really be sensor related or anything except the tune can it?

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Everything works the same way... Pretend it's an XR6 or something :D

 

Just need to find out if the tune is just wrong or if it's actually cactus.

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different ecu's will have different issue's, could be from a different cc bike? or if you know its all the same then might have been tuned at some point?

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All I know about it is that it was installed on the bike by the original owner at one point but was then removed by a mechanic because of "running issues" according to the service records - i.e. running stupidly rich as I found out.

 

There was the pink marker that wreckers use on it indicating it was from the same model bike but a year earlier. AFAIK nothing changed between years.

 

 

There is a chance it could have been from a track bike or something which would explain why it had a fat tune - but you would think the mech would just re-flash it instead of replacing the entire thing if that was the case.

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Not all mechanics have the equipment to re-flash/tune every model/variant.

Normally the tools mechanics have for ECUs allow reading codes, testing features and resetting codes and other small things.

Full reset would be a dealer thing in a lot of cases.

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This keeps getting weirder.

 

Used the rich ecu but removed all intake and exhaust restrictions and it actually got worse - huge flat spot up to 3.5krpm but still running rich.

 

Not sure what to make of that, logic would say leaning it out would help, if only a little but it actually made it worse?

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That thought crossed my mind but the fact that it actually did cause a flat spot means it must have done something to the AFR.

 

But it has me scratching my head because leaning it out should have made it better not worse.

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Well this sure is confusing...

 

All restrictions back on (stock air intake and exhaust baffling). It still has a flat spot and crappy initial throttle response but it bogs down a lot less than before (no restriction or one of those two things).

 

The exhaust still smells like a petrol station and it still runs cold though.

 

It's contradicting itself. Might just have to put this down to "EFI is the devil".

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okay,

 

Fuel pressure, put a gauge on it to see if it is within spec, then look at pump or the fuel reg.

Check coolant and air temp sensors - if they are out of spec for resistance then the system will inject more to protect the engine or it thinks it is cold.

 

start there.

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I should mention that with the stock ECU none of these issues happen so you'd think it would be ECU related or it'd do it all the time?

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