Missfire Emerald ecu

[Landracer33]

I have an Emerald ecu running my LS2, the ecu was previously mapped at emerald when fitted to another LS2, however I have a lumpy tickover and when opening the throttle and entering load site 4 it badly missfires.
It’s firing on all 8 and checked continuity of the Wiring, the crank sensor is shielded.
I have run the data logger and cannot see anything obvious.
Any suggestions?

Edited by Landracer33 on Sunday 12th July 10:03

[stevieturbo]

Landracer33 said:

I have an Emerald ecu running my LS2, the ecu was previously mapped at emerald when fitted to another LS2, however I have a lumpy tickover and when opening the throttle and entering load site 4 it badly missfires.
It’s firing on all 8 and checked continuity of the Wiring, the crank sensor is shielded.
I have run the data logger and cannot see anything obvious.
Any suggestions?

Edited by Landracer33 on Sunday 12th July 10:03

Presumably it did not always do this ? When did it last run good, and what has changed if anything from then ?

And if you're saying it has a lumpy tickover...AND at a load site...or presumably multiple load sites it also misfires, simply because it must be misfiring at idle too ?

So it's misfiring everywhere ?

If it was firing on all 8...surely it would not be misfiring ? So exactly what do you mean by that ? What has been tested ?
Have you confirmed a viable spark and at sensible times at all 8 plugs ?

Have you tried unplugging injectors, to see if it runs worse, or nothing changes ? to try and see if it is a particular cylinder ?

Any tests to confirm fuel is being injected on all 8 ?

What do the plugs look like ? If they're wet...bin them,

Edited by stevieturbo on Sunday 12th July 10:29

[Landracer33]

It’s new vehicle build so it hasn’t run before. However the ecu was previously fitted to a similar LS2 that ran fine.
I’ve had a ignition light on each lead and seems to have a consistent spark on all 8.
I’ve unplugged the injectors and coils individually and the engine note drops each time, indicating all are operating.
Ive even took the coil/injector feed out of the loom to rule out interference/noise.

[stevieturbo]

So it has never been run or tuned on this vehicle ? red flag there...never assume two will be the same.

Have you checked the plugs ? First obvious step.

If it has a misfire, then unplugging one injector at a time will make a difference when you get to a bad cylinder....ie in that it will make no change to running.

As you do not mention, I presume you have no idea what fueling is like overall, or even on either bank at idle ? Get a wideband or a gas analyser.

Widebands are cheap, at least this will help give you an idea of whether it is far too rich, lean, something ( with the caveat misfires can screw with the readings )

Presumably as you have access to the ecu, all sensors are reporting sensible values etc ?

Are you sure all injectors and coils are wired correctly ? ie correct firing order ?

Really, basic checks first, even more so as it's a first time run.

[GreenV8S]

The fact it runs at all is a good sign, but since this is a new installation it needs thorough checking out to make sure all the sensors and actuators are working correctly, and then calibrating. You could potentially DIY the checking if you have a basic understanding of the engine management system and basic electrical skills. It would be much easier for somebody with experience of the ECU though.

[stevieturbo]

I doubt the ecu is the problem to even be thinking along those lines.

running is good yes....but could still mean there are wiring issues etc.

I know when I've been messing with things I've had mine running on 4 cylinders...and it really wasnt as bad as you'd think.
Off one cylinder can be very difficult to tell if you've no means of diagnosis, and perhaps even more so if the engine has never actually ran before either. Some might think it is normal.

But lambda on each side would give info, plugs would give info, even as simple as measuring temp on each exhaust runner to see if one or more are not firing.
Lots of easy ways to determine which cylinder is off, and also what fueling is like...and of course checking timing etc.

Just basic first steps really that apply regardless of engine, regardless of ecu.

[Landracer33]

Thanks for advice, but found the problem. The crank sensor was set as inductive not digital

[stevieturbo]

Good spot....that could have been very dangerous, as with it at VR, timing would have been all over the place with rpm.

It should have been flagging up crank errors or rpm displayed on ecu would have been erratic ?

[Landracer33]

Bizzarly it ran with a slight miss , it was only when it entered load site 4 that it wen’t really bad.

[stevieturbo]

Landracer33 said:

Bizzarly it ran with a slight miss , it was only when it entered load site 4 that it wen’t really bad.

Ignition timing will have been all over the place, and get worse with higher rpm's

Surprised the ecu wasn't shouting about some sort of errors, as the crank signal would have made very little sense to it.