Idle hunt

[Bitsyncmaster]

Working on the software I did some more testing of the stock ECU.

1). Stock ECU takes 8 to 9 seconds to step the duty cycle from one extreme to the other. My ECU with the half second wait takes about 60 seconds. I tested mine with a 1/4 second wait and it got some hunting at idle. So it looks like that 300 ms O2 sensor response time I read about is about right.

2) Doing the book testing which has you float, ground and 1.5 volt battery testing does keep that stock step rate. Ground and 1.5 volt is just so the input is below or above 0.5 volts. It still runs closed loop. So doing that testing with my ECU will take 6 times as long to see the min and max duty cycle. You can do that testing without the engine running if you jumper the RPM relay brown wire pin to the double yellow/red wire pin.

3) Wide open throttle also takes that same rate of change with the stock ECU. I think I will make my ECU change to that 55% dwell instantly on and normal closed loop timing for off.

When I get my first circuit boards I have to add an IC for a change needed to sense when the O2 input is floated (disconnected).

[DMC5180]

Dave, I just stumbled on this thread. For clarity, which ECU are experimenting with. Lambda or Idle ECU?


Sent from my iPhone using Tapatalk

[Bitsyncmaster]

Dave, I just stumbled on this thread. For clarity, which ECU are experimenting with. Lambda or Idle ECU?


Sent from my iPhone using Tapatalk

Lambda ECU. It's better to fix the cause of idle hunt rather than try to find a fix via other means.

[DMC5180]

In that case, I?m open for any testing. Just went for nice drive today and the pesky hunting is still there no matter how I?ve configured your Idle ECU.


Sent from my iPhone using Tapatalk

[Bitsyncmaster]

In that case, I?m open for any testing. Just went for nice drive today and the pesky hunting is still there no matter how I?ve configured your Idle ECU.


Sent from my iPhone using Tapatalk

I've got 3 circuit boards that should be here Wednesday. One is going to a local owner with "hot" camshafts for testing. Turns out high duration camshafts fake out the O2 sensor at idle speeds feeding more air into the exhaust. I will need to keep one for my R&D work doing software and getting a larger order ready.

So far the only reason for my ECU is to cure idle hunt. The stock ECU only draws about 50 ma and mine will be much less but heat does not seem to be an issue in the drivers side cubby.

[DMC5180]

Great, I?ve got Stage II setup with there Cams. Not as Aggressive as some I?ve heard though. How invasive is what you are doing?


Sent from my iPhone using Tapatalk

[Bitsyncmaster]

Great, I?ve got Stage II setup with there Cams. Not as Aggressive as some I?ve heard though. How invasive is what you are doing?


Sent from my iPhone using Tapatalk

Plug and play. So far no reason to have any user adjustments inside the units. Of course I will need a core. You can test my unit without removing your ECU because the connector can be unplugged and then plugging my unit in with it sitting somewhere with the open cubby. At least my car's harness can do that.

[DMC-Ron]

Or, if you want to test on a totally original set up, I'm happy to volunteer.

Ron

[DMC5180]

I grabbed a couple 033?s for cores. $28 ea including shipping. The 023?s from the same seller were $85 . Not sure the difference other than 033 listed for volvo 240 and 023 listed volvo 260.


Sent from my iPhone using Tapatalk

[Bitsyncmaster]

I grabbed a couple 033?s for cores. $28 ea including shipping. The 023?s from the same seller were $85 . Not sure the difference other than 033 listed for volvo 240 and 023 listed volvo 260.


Sent from my iPhone using Tapatalk

I think the black Volvo units will work with the same PCB. I have some black ones already.