Idle hunt

[Bitsyncmaster]

First owner with the stage 2 found my lambda ECU did stop idle hunting. He still has a problem with my idle ECU with his auto transmission getting hunting when slow driving parking lot speeds. My idle ECU would get into a throttle increase. Not sure how to find that problem since I have a manual transmission.

Second owner should get my lambda ECU on Friday.

Have been thinking. Wish I could find the female pins for the lambda ECU connector. Our ECU connector has a few extra unused pin but the mating harness connector has no pins installed into those positions. I would like to drive an LED output signal from one extra pin. I could make that LED turn green with dwell between 35 and 45 deg. Make it turn red when dwell is at min or max. I am doing that with an LED on my circuit board but to see it you will need to drill a hole in the ECU case.

Also with an extra pin I could input the ignition advance solenoid signal and know when the engine is at idle. I could use that to have my ECU run slow (that prevents idle hunt) or run the same speed at the stock ECU when not at idle.

[Bitsyncmaster]

Here is a photo of the hybrid unit in all the stock lambda ECUs (cover removed).

Just interesting for the electronic gurus. The O2 sensor feeds directly into this unit. Not sure what it does and wonder if that micro circuit is analog or digital. I would not think it's a micro since early 80's they did not have micros with clocks or memory.

[Michael]

Once you get this figured out, is that something you could do to existing ecu's? I've had mine on a shelf for a few years because I had the exact idle surge issues in my stage II.

[Bitsyncmaster]

Once you get this figured out, is that something you could do to existing ecu's? I've had mine on a shelf for a few years because I had the exact idle surge issues in my stage II.

Yes. My circuit board replaces the stock board. So far plug and play.

[Timeless]

I have an extra ECU as well and would be interested. Stage 2 automatic car.

[Dhennick99]

I'm running a stock auto and have had issues with idle hunt as well. I'd be curious in updating when Dave is ready.

[Bitsyncmaster]

I've had three users with auto stage two users still get problems when using my idle ECU along with my prototype lambda ECU. It looks like I need to do work on the idle ECU to correct that. But any warmup hunting issues seem to go away with my lambda ECU.

I have done more work on the software for the lambda ECU. I now have fine adjustment of dwell (1024 steps) and a duel speed of that adjustment. I was able to do that by averaging 256 readings of the O2 sensor voltage over a 1/4 second time. Not sure if that will help anything but it doubles my speed of change when needed.

I think I'm ready to order the production circuit boards.

[Bitsyncmaster]

I was working on my idle ECU software. Trying to fix a problem people have with an auto with stage 2 installed. Hard to find that problem since my car does not have either. Anyway I found a nice improvement for even my car. I was getting the RPM value timing between two ignition pulses. Well I changed that RPM value to time between 6 pulses so it always starts the timing on the same distributor "lobe". That removes any inaccuracy of the lobe spacing and pickup variance because it always starts timing on the same lobe. Now my RPM gauge is "nailed" solid except for an occasional miss fire. I have to track down that miss fire cause.

I would not think that fix affects the problem I was looking for.

[Bitsyncmaster]

I should get 40 production lambda circuit boards tomorrow.

I've been playing with the idle ECU and thought of a way to measure how good the idle holds. I just put in the idle ECU software a check on every other ignition pulse to output a trigger signal when it goes below 50 RPM or above 50 RPM from the set idle RPM. I will keep tightening up on those values until I can put a counter on that trigger to give a a value I can use to measure any improvements.

[Michael]

I should get 40 production lambda circuit boards tomorrow.

I've been playing with the idle ECU and thought of a way to measure how good the idle holds. I just put in the idle ECU software a check on every other ignition pulse to output a trigger signal when it goes below 50 RPM or above 50 RPM from the set idle RPM. I will keep tightening up on those values until I can put a counter on that trigger to give a a value I can use to measure any improvements.

If you need a stage II test mule, I'm game. My ecu has been on a shelf for like 6 or 7 years.