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RESOLVED: Idle Bouncing - 1g DSM 2.3L 4g63 - VR4 G4+

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RESOLUTION: 1990 1G AWD DSM uses an ISC with reversed stepper motor direction.  Unknown if this is standard for DSMs or if that's only for particular years.

 

Hey, guys.  I'm just getting set up and I'm finding that my idle bounces pretty wildly after warm-up.  It bottoms at the target idle around 1k RPM, but then immediately jumps to 2-2.3k RPM.  This is with the Base Idle Set Screw (BISS) all the way in and I've checked for vac leaks and other strange items. ISC solenoid has been confirmed to work, but I'm uncertain if the standard settings for the VR4 are the same for a '90/'91 model.

It seems the only reason the idle drops is that it cuts fuel after a moment, since the AFRs/Lambda drop out for a split second.  I've pulled timing in that area and it seems to have softened the bouncing to only around 2k, but it's still pretty unstable.  Unstable probably isn't the correct word because it is very predictable with a set period and only occurs after the car has warmed up a bit.

Any 1G DSM (Eclipse, Talon, Laser) guys out there that have experienced something similar on a G4+?

Edited by Architechnik
Update with resolution

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Here's the log and the PCL file.  

I was playing with the ISC settings to see if they made a difference, so they might be out of whack, but I didn't really get a response on that end anyway.

If there are other metrics I should run, I'd be happy to grab another.

7-10-17.pclr

Log 2017-07-13 7;41;47 am.llg

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Try more even numbers in the VE map. You are touching cells running from 45 to 70`ish while fluctuation. Also try simlar numbers in the timing table until you get it stable.

Turn of closed loop idle control until you get a good base. It will only chase its tail until its right. You will need to get the base table correct`ish first.

Turn of overrun fuel cut for now. You are running in and out of it.

Fix that anv 5 error code.

When it is as good as it gets then you can turn on closed loop idle (but you will need to tune the pids also) and also i recomend using ignition idle control. Its a very powerfull tool for getting a stable idle.

 

Edited by Steve

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Okay, thanks.  I'll try that out.
How do you turn off closed loop idle control?  Is it just changing all the values to max out?  I'll probably just unplug it after base position reset.

 

Actual injector size is unknown, so I'll try decreasing the size of injectors to drop the VE numbers (and hopefully smooth that out). 

Overrun fuel cut is off and I'll look at resetting it later.

The ANV 5 error isn't actually an error; the 0v condition is from the Wideband O2 sensor going completely lean after warm up and before starting.


I'll look into the ignition controlled idle next.  

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Se attached photo. Big yellow square on top left corner. To top row says closed loop sol/stepper. Hit that and you get the box in the middle. Choose open loop here.

Dont unplug it. You need to set the numbers in the idle position base table to get propper numbers.

 

Unknown injectors doe NOT help your case at all. I would do what i could to find out what injectors you got and the propper deadtime values. It is an important aspect of running an VE based fuelmodel

Screenshot 2017-07-14 18.50.26.png

Edited by Steve

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The prior configuration had them set to 805 on an ECU that was looking for a 2.0L engine when it has a 2.3L. 

They are FIC injectors, which advertise a +330 microsecond adjustment over stock injector settings.  I may make small adjustments there, as I have found on previous builds that they have a more gradual deviation than just a flat increase.

 

Is there a repository for layouts?  Can you send me the one you have here?

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Okay, I figured out a lot of what was going on: the ISC was almost all the way open.  I put it in open loop mode and was revving up to 2k rpm and staying there.  I popped the charge hose off the throttle body and found the ISC inlet gulping down air and the idle dropped immediately when I put my finger over it.  

I started playing with the base numbers and found contrary to what most people were saying that more steps is more closed, I found just the opposite.  Dropping the base steps to 0 closed the ISC; it looks like my ISC valve is reversed.  Hit that item and put it back to closed loop and it works like a charm.

 

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RESOLUTION: 1990 1G AWD DSM uses an ISC with reversed stepper motor direction.  Unknown if this is standard for DSMs or if that's only for particular years.

This is a known issue and should have been made fairly clear in the printed quick start guide that came with the ECU:

 

 

UkWtNhb.png

Edited by Adamw

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On 7/16/2017 at 10:06 PM, Architechnik said:

Okay, I figured out a lot of what was going on: the ISC was almost all the way open.  I put it in open loop mode and was revving up to 2k rpm and staying there.  I popped the charge hose off the throttle body and found the ISC inlet gulping down air and the idle dropped immediately when I put my finger over it.  

I started playing with the base numbers and found contrary to what most people were saying that more steps is more closed, I found just the opposite.  Dropping the base steps to 0 closed the ISC; it looks like my ISC valve is reversed.  Hit that item and put it back to closed loop and it works like a charm.

 

Sorry to bump this from the grave, I'm new to the Link Ecu and I'm looking for the ISC step page, could you link a pic of the window i should be looking for?

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10 hours ago, Blk2gdsm said:

Sorry to bump this from the grave, I'm new to the Link Ecu and I'm looking for the ISC step page, could you link a pic of the window i should be looking for?

Im not sure what you are looking for but the adjustment that is discussed in the post you quoted is the Idle base position table, you will find this in the idle speed control menu.  

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