idle question

[c21vhpd]

How does the M3DK ECU achieve the required rpm in the bit of the map that sets 'Target RPM' vs cooling temperature? I've recently had the ECU and Jenvey DTHTBs fitted, and my cold idle is v poor - I have to keep the throttle open when at rest for the first couple of minutes, which is OK, but there are a lot of junctions to heel and toe to a halt at when I keave my house!

 

If I just open the idle screw on the Jenveys a bit more to improve the cold idle, will the M3DK still be able to achieve the target rpm at higher temperatures? What's to stop me opening the idle screw all the way and letting the ECU take over? (I'm ignorant you see, hairdresser's car an' all )

 

Honda Passion Orange, 640kg , and proud of it 😬

[scooby dooby doo]

Let me known when you've sorted it - and I'll pop round

 

HOOPY 500 kg R706KGU

[scooby dooby doo]

ARGH ❗ triple post ❗

its suddenly gone very funny and given loads of 500 errors...

 

HOOPY 500 kg R706KGU

 

Edited by - hoopy on 26 Nov 2002 00:49:21

[scooby dooby doo]

oops ❗ double post...

 

HOOPY 500 kg R706KGU

 

Edited by - hoopy on 26 Nov 2002 00:48:56

[Peter Carmichael]

If you have an idling problem when warming up it is all down to the fuelling corrections. You can get this perfect with a bit of effort, as described here

 

 

[scooby dooby doo]

aha ❗ Right then craig - the saturday after the cam7 xmas dinner shall we give it a go 🤔

(I've not got a laptop so you outstandingly large screened item will be v. useful

 

HOOPY 500 kg R706KGU

[Peter Carmichael]

I have had some recent clarification on the fuelling from Emerald themselves. The Emerald works on a bunch of corrections to the fuelling.

 

RUNNING_FUEL = BASE(rpm,load) * (1 + COOL%(coolant degC) * CORR%(rpm)) * (1+AIR%(air degC))

CRANKING_FUEL = BASE(0,load) * (1 + COOL%(coolant degC) * CORR%(rpm)) * (1+ AIR%(air degC)) * (1+ CRANK%(coolant degC))

 

"The engine is determined to be cranking if the rpm is between 0 and 500 rpm. Once the 500 rpm threshold is reached the engine is determined to be running.... if the rpm drops down below 500 rpm it is still thought of as running (assuming it doesn't stall).

 

"When "cranking" the full cranking enrichment is applied. As soon as the engine is "running" the cranking enrichment is immediately reduced by 50% and the rest starts to decay away at a fixed rate (usually takes around 10-15 seconds to be completely out of the equation)."

 

"The software interpolates between all points and applies the corrections. ie. the coolant temp corrections applied are calculated from the interpolation between the settings at 10 degC and 20 degC, the same goes for the air temp corrections. The base(rpm,load) fuelling is interpolated at all times - ie. for rpm and load. As the rpm is < 500rpm there are no speed interpolation calculations until after the 500 rpm threshold is reached..."

 

------------------------------------------------------------------

 

What this means is that for starting with no throttle, the only setting in the fuel map that has an effect is the LOAD SITE ZERO/SPEED SITE ZERO site.

 

The other things to sense check are:

- rpm correction for coolant enrichment - consistent settings around idle and a ramp down as revs rise.

- fuel map at idle - settings about the idle position should give a gentle ramp of fuel as revs fall.

- air temp corrections - should be minimal and deal with the air density changes at the temperature extremes

- load site 15 fuelling should follow the torque curve - the torque peak rpm should correspond to the highest fuelling value. The fuelling should drop away after the torque peak.

- load site 15 duty percent should follow the power curve - the power peak rpm should correspond to the highest duty cycle value. The duty cycle should drop away gently after the power peak.

- cross check fuelling at power peak and torque peak - the power peak fuelling value should be close to 90% of the torque peak fuelling

 

 

Example "rpm correction for coolant enrichment" settings:

 

Coolant correction:

100 100 100 90 82 77 73 56 36 20 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15

Example Fuel map settings at load site zero:

Injection map:

31 29 27 25 24 23 22 21 20 20 20 19 19 19 19 19 19 17 16 15 14 0 0 0 0 0 0 0 0 0 0 0

Example air temperature corrections:

Air ignition:

0 0 0 0 0 0 0 0 0 0 0 0 0 0

Air fuel:

4 2 2 1 0 0 0 0 0 0 -1 -2 -4 -4

Example power peak and torque peak checks:

Load site 15 fuelling:

0 0 54 58 68 65 66 70 76 84 92 101 109 110 112 112 109 104 99 91 80 0 0 0 0 0 0 0 0 0 0 0

Torque peak...................................^ 7250rpm....^

99 is 88% of 112. It makes the 112 fuelling at the torque peak look

wrong. 7250rpm is also a bit later in the rev range than the actual torque peak

which was at 6500rpm. I suspect that the two 112 values should actually be 110.

Load site 15 duty cycle:

0 0 5 9 14 17 20 25 31 38 47 56 67 73 80 85 89 90 91 88 81

Power peak.................................................^ 9000 rpm

 

Edited by - Peter Carmichael on 26 Nov 2002 13:45:25