Kroon Harness for 944 Turbo

[Mscromer]

I don't trust the F9 log re the idle stabilizer. At least on mine, it seems to read backwards -- i.e., when it says 90% open, it's really 90% closed. I've flagged that before here on CP, and pinged Joe about it, but never got a response. I'll see if I can do a little testing this week to prove or disprove that.

But to your question, if you had a vacuum leak, you would expect the ISV to close more to keep the idle at its commanded rpm...

The map sensor thing with the F9 DME is real and we documented it in detail in the chip tuning guide, but it's a super subtle issue though. On a stock chip, the result is an idle set to 800 rpms rather 840, which makes for slower/weaker idle but otherwise no real issues. Like I said, it went unnoticed to the world, including Joe, until we went on a quest to control idle rpms in the maps and realized this quirk sent the code to a vestigial idle map set to 800.

My car has a little bit bigger cam so that might have compounded the F9 DME quirk, but on my car it was a significant difference. My car idled like total crap until I shorted out the MAP plug.

[turbotoys]

I don't trust the F9 log re the idle stabilizer. At least on mine, it seems to read backwards -- i.e., when it says 90% open, it's really 90% closed. I've flagged that before here on CP, and pinged Joe about it, but never got a response. I'll see if I can do a little testing this week to prove or disprove that.

But to your question, if you had a vacuum leak, you would expect the ISV to close more to keep the idle at its commanded rpm...

The map sensor thing with the F9 DME is real and we documented it in detail in the chip tuning guide, but it's a super subtle issue though. On a stock chip, the result is an idle set to 800 rpms rather 840, which makes for slower/weaker idle but otherwise no real issues. Like I said, it went unnoticed to the world, including Joe, until we went on a quest to control idle rpms in the maps and realized this quirk sent the code to a vestigial idle map set to 800.

It's interesting that you say this, Tom. I've sworn that my ICV is operating in reverse, or maybe I don't have the idle set correctly. I did attach the orange and black wires together, and it seems to have made the last little bit of difference in smoothness. When starting cold, the data logger shows a low ICV % open, and when warm, it goes up towards the 80s and 90s, but the idle behavior is reversed. Cold, it runs around 750 RPM and warm it trends towards 850-900 RPM and when I turn the AC on, it doesn't adjust the idle as I would expect and pulls the RPM down.

I draw a solid vacuum and have smoke tested everything more than I care to admit

Any thoughts on this?

[NCGermerican]

I don't trust the F9 log re the idle stabilizer. At least on mine, it seems to read backwards -- i.e., when it says 90% open, it's really 90% closed. I've flagged that before here on CP, and pinged Joe about it, but never got a response. I'll see if I can do a little testing this week to prove or disprove that.

But to your question, if you had a vacuum leak, you would expect the ISV to close more to keep the idle at its commanded rpm...

The map sensor thing with the F9 DME is real and we documented it in detail in the chip tuning guide, but it's a super subtle issue though. On a stock chip, the result is an idle set to 800 rpms rather 840, which makes for slower/weaker idle but otherwise no real issues. Like I said, it went unnoticed to the world, including Joe, until we went on a quest to control idle rpms in the maps and realized this quirk sent the code to a vestigial idle map set to 800.

It's interesting that you say this, Tom. I've sworn that my ICV is operating in reverse, or maybe I don't have the idle set correctly. I did attach the orange and black wires together, and it seems to have made the last little bit of difference in smoothness. When starting cold, the data logger shows a low ICV % open, and when warm, it goes up towards the 80s and 90s, but the idle behavior is reversed. Cold, it runs around 750 RPM and warm it trends towards 850-900 RPM and when I turn the AC on, it doesn't adjust the idle as I would expect and pulls the RPM down.

I draw a solid vacuum and have smoke tested everything more than I care to admit

Any thoughts on this?

I'm glad you chimed in, but now I don't know what to believe. When I first start up the car, it's in the mid 70's % open. After fully warm, it's at 93% open. Now, if that's correct, it could explain a lot of things (on my car). If it's that far open, it could definitely cause a low engine vacuum situation because it's letting in WAY more air than it should. On the other hand, if it's 93% CLOSED.....wouldn't the car want to stall?

Everything I have read about setting the idle is 1) get to operating temp and 2) bypass the ICV with the diagnostic port. To set the idle adjustment screw, it says to screw it all the way in and back it off 1.5 (or maybe 2.5?) turns. I have to unscrew it MUCH more than that for the car not to struggle. Maybe 3-5 turns.

[Tom]

I posted this in a separate thread but see this video for pretty compelling evidence the F9 data log is directionally backwards…. The ISV itself seems to work as intended, but the % Open reported in the logging software just seems wrong.

[944m3]

I recently learned that MaxxECUs display both the open and closed duty cycle. This was confusing me at first but after some research I learned that opposite voltage is applied to counter the opening voltage. So for example, on the MaxxECU I can disable the opposite or closing voltage. When I do that the open duty cycle shoots up, because there is nothing opposing it. Let’s say open duty cycle is 10% the close duty cycle is 80%. This is clearly reported on the MaxxECU.

It seems that maybe the F9 is reporting the closed duty cycle.

[Tom]

I recently learned that MaxxECUs display both the open and closed duty cycle. This was confusing me at first but after some research I learned that opposite voltage is applied to counter the opening voltage. So for example, on the MaxxECU I can disable the opposite or closing voltage. When I do that the open duty cycle shoots up, because there is nothing opposing it. Let’s say open duty cycle is 10% the close duty cycle is 80%. This is clearly reported on the MaxxECU.

It seems that maybe the F9 is reporting the closed duty cycle.

Yes, that possibility occurred to me, but you’d have to be pretty deeply buried in slide-rules to interpret “Idle Control Valve % Open” as anything other than what it says, no?

Also, the ISV has three terminals. It receives 12 V on the center terminal, while the DME modulates the ground applied to the two outer terminals -- one driving the valve toward open and the other toward closed. Applying 100% duty to one winding and 0% to the other would drive the valve fully in one direction.

So even if Focus 9 is displaying a PWM duty cycle rather than actual valve position, the reading is not meaningful unless it identifies whether it is the opening-winding duty, the closing-winding duty, or some calculated balance between the two. Labeling it simply “Idle Control Valve % Open” just seems like a mistake to me, even if there were some engineer-think that led to that label.... I'm hoping Joe chimes in, because as it stands, I can't say with confidence what that number really means...

[turbotoys]

I don't trust the F9 log re the idle stabilizer. At least on mine, it seems to read backwards -- i.e., when it says 90% open, it's really 90% closed. I've flagged that before here on CP, and pinged Joe about it, but never got a response. I'll see if I can do a little testing this week to prove or disprove that.

But to your question, if you had a vacuum leak, you would expect the ISV to close more to keep the idle at its commanded rpm...

The map sensor thing with the F9 DME is real and we documented it in detail in the chip tuning guide, but it's a super subtle issue though. On a stock chip, the result is an idle set to 800 rpms rather 840, which makes for slower/weaker idle but otherwise no real issues. Like I said, it went unnoticed to the world, including Joe, until we went on a quest to control idle rpms in the maps and realized this quirk sent the code to a vestigial idle map set to 800.

It's interesting that you say this, Tom. I've sworn that my ICV is operating in reverse, or maybe I don't have the idle set correctly. I did attach the orange and black wires together, and it seems to have made the last little bit of difference in smoothness. When starting cold, the data logger shows a low ICV % open, and when warm, it goes up towards the 80s and 90s, but the idle behavior is reversed. Cold, it runs around 750 RPM and warm it trends towards 850-900 RPM and when I turn the AC on, it doesn't adjust the idle as I would expect and pulls the RPM down.

I draw a solid vacuum and have smoke tested everything more than I care to admit

Any thoughts on this?

I'm glad you chimed in, but now I don't know what to believe. When I first start up the car, it's in the mid 70's % open. After fully warm, it's at 93% open. Now, if that's correct, it could explain a lot of things (on my car). If it's that far open, it could definitely cause a low engine vacuum situation because it's letting in WAY more air than it should. On the other hand, if it's 93% CLOSED.....wouldn't the car want to stall?

Everything I have read about setting the idle is 1) get to operating temp and 2) bypass the ICV with the diagnostic port. To set the idle adjustment screw, it says to screw it all the way in and back it off 1.5 (or maybe 2.5?) turns. I have to unscrew it MUCH more than that for the car not to struggle. Maybe 3-5 turns.

Dennis... I just looked at my startup logs today. Note it's HOT out and my starting ICT temps were 99F. The ICV was closed down to 10% ish and got to 40% within a minute. Now.. My issue is that the cold idle is in the 750 range and when warm heads towards 850.

Tomorrow, I'm going to get it up to 195F and properly set the ICV and idle and see if the grounding of the orange/black makes a difference. I'll let you know