VegasAWD Posted August 23, 2021 Report Share Posted August 23, 2021 Hi, I'm running the plug-n-play Vr4+ for early model 4g63 (1g DSM) and I'm having strange idle activity 1) The isc polarity is reversed. I found a thread that stated the 1990 DSM isc is reversed but my car absolutely doesn't have a 90 isc and shouldn't be reversed. In regular polarity, Link raises the idle when I increase the steps which is the opposite of what it should do. 2) I currently have my engine fan step to 40 for whatever reason and when I zero it out to work on my idle position it actually wants to stall the car....when the fans aren't even on. How could engine fan step affect the car's idle with no fan on? 3) Because I had to reverse the polarity of the isc per Link instructions to get the idle to decrease when step is increased, wouldn't my step add-ups like engine fan step actually decrease my idle when activated? I hope that makes sense, but if my base step is say 60 and engine fan step is 20 then when the fan comes on I now have a total position of 80 which lowers my idle when fan comes on? 4) Final question, stock DSMs are set so that when warmed up, the isc should be hitting 30 steps from closed to have optimal idle control. Is this something I should try and achieve through the BISS screw or should I now worry about for Link. Stock dsm idle step is 0-120 steps with 30 being the preferred place to idle at with no accessories on. Thanks for any help. Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 23, 2021 Report Share Posted August 23, 2021 Attach the tune and a log. The idle position number will get smaller when a fan or AC step is enabled. i.e. the step is subtracted not added when using a stepper. Quote Link to comment Share on other sites More sharing options...
VegasAWD Posted August 24, 2021 Author Report Share Posted August 24, 2021 You can see in the fan step log that the rpms drop when I zero out the fan step. It's also weird that my idle base position table is so narrow. From cold to hot it only changes like 15 steps. Maybe that's normal. Quote Link to comment Share on other sites More sharing options...
VegasAWD Posted August 25, 2021 Author Report Share Posted August 25, 2021 @Adamw Quote Link to comment Share on other sites More sharing options...
Electredge Posted August 25, 2021 Report Share Posted August 25, 2021 On 8/24/2021 at 8:19 AM, VegasAWD said: You can see in the fan step log that the rpms drop when I zero out the fan step. It's also weird that my idle base position table is so narrow. From cold to hot it only changes like 15 steps. Maybe that's normal. eTune#4d.pclr 166.13 kB · 0 downloads fan step.llg 604.19 kB · 0 downloads idle forum.llg 2.13 MB · 0 downloads load this and get another log https://drive.google.com/file/d/1GIeXhHrD0mwn8ulImP7aqURwp2n6ozR4/view?usp=sharing Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 25, 2021 Report Share Posted August 25, 2021 The settings in the tune you attached dont seem to match the log. i.e the tune is set to open loop but the log shows it was in closed loop. Can you give us the tune that was actually used when the logs were done? A couple of fixes needed before doing more logs: Fan step wont work since FAN 2 is always on. Since you dont have a Fan 2 or 3, set fan 2 & 3 to 150°C so they never trip the fan step. ECU hold power keep alive time is set to 0, so the idle valve may not reset after key off. Set this to 5 secs, then switch ign off for at least 5 sec before restarting and confirming base position is still ok. Not quite sure why idle status shows hold timer a lot in your log so need to see the actual tune to diagnose that. Quote Link to comment Share on other sites More sharing options...
VegasAWD Posted August 26, 2021 Author Report Share Posted August 26, 2021 6 hours ago, Electredge said: load this and get another log https://drive.google.com/file/d/1GIeXhHrD0mwn8ulImP7aqURwp2n6ozR4/view?usp=sharing Thanks, I'll give that a try. Quote Link to comment Share on other sites More sharing options...
VegasAWD Posted August 27, 2021 Author Report Share Posted August 27, 2021 On 8/25/2021 at 5:37 PM, Adamw said: The settings in the tune you attached dont seem to match the log. i.e the tune is set to open loop but the log shows it was in closed loop. Can you give us the tune that was actually used when the logs were done? A couple of fixes needed before doing more logs: Fan step wont work since FAN 2 is always on. Since you dont have a Fan 2 or 3, set fan 2 & 3 to 150°C so they never trip the fan step. ECU hold power keep alive time is set to 0, so the idle valve may not reset after key off. Set this to 5 secs, then switch ign off for at least 5 sec before restarting and confirming base position is still ok. Not quite sure why idle status shows hold timer a lot in your log so need to see the actual tune to diagnose that. 1) Great catch @Adamw . That fan2/3 mess-up fixed that particular fan step issue, but you'll see in the log I activate the fan, the idle drops, then I double the fan step and it doesn't really do anything. Any advice here? Maybe I just don't know what I'm looking at. 2) You'll also see the isc polarity is reversed when it shouldn't. It's without a doubt not a 90 isc and I just came over from the 91+ OEM ecu. 3) You'll also see that as temps rise my base step goes all the way up rough 100 steps out of 120. I'm almost completely maxed out on how low I can physically make the idle go through the biss screw/throttle body. The oem service manual states to set the idle at 30 steps from closed when the car is fully warmed up and no accessories. This would equate to a base idle position of 90 in Link. Is that something I should strive to achieve in Link G4+ or should I not care? Thanks Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 27, 2021 Report Share Posted August 27, 2021 The numbers in the base position table follow the correct trend so the motor direction appears correct. Your base position numbers look like they should be ok to me. I would do the idle ign table a bit different than it currently is. Stepper motors are slow to move so you generally want quite low ign timing for normal idle, this means there is greater capability for the ecu to quickly increase torque when it is required due to a fan turning on or whatever. This lower timing will bring the idle speed down for the given idle valve position too. Try the attached. Base position will likely need a tweak, or turn closed loop on and log what base position it settles on. Give us a log with the fan turning on if it is still no closer. linkforumidle V1.1.pclr Quote Link to comment Share on other sites More sharing options...
VegasAWD Posted August 27, 2021 Author Report Share Posted August 27, 2021 On 8/26/2021 at 10:50 PM, Adamw said: The numbers in the base position table follow the correct trend so the motor direction appears correct. Your base position numbers look like they should be ok to me. I would do the idle ign table a bit different than it currently is. Stepper motors are slow to move so you generally want quite low ign timing for normal idle, this means there is greater capability for the ecu to quickly increase torque when it is required due to a fan turning on or whatever. This lower timing will bring the idle speed down for the given idle valve position too. Try the attached. Base position will likely need a tweak, or turn closed loop on and log what base position it settles on. Give us a log with the fan turning on if it is still no closer. linkforumidle V1.1.pclr 166.17 kB · 3 downloads Hi @Adamw, I've uploaded the tune and log with the fan turning on. All-in-all it's idling well. Please take a look and see if there is anything else I can make changes to. The fan didn't bog down the idle this time. Next thing I need to work on is the idle on startup. It kind of struggles at first and hasn't responded well to increases in startup step in previous tries. I can get some startup logs if you're willing to help. Thanks Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 27, 2021 Report Share Posted August 27, 2021 Yep will need to see a start up log. It may be more fuel related than air, so allow the wideband to warm up before starting so we can see what is going on there too. Quote Link to comment Share on other sites More sharing options...
VegasAWD Posted August 28, 2021 Author Report Share Posted August 28, 2021 Hi @AdamwI took a quick startup log. Thanks. Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 28, 2021 Report Share Posted August 28, 2021 Yeah I would say it is more a fuel related issue. The idle valve is near wide open so not much more it can do. Ethanol and some types of injectors with poor atomisation may never work well for cold start. But your lambda if working suggests there is a lot of excess fuel. Quote Link to comment Share on other sites More sharing options...
VegasAWD Posted September 4, 2021 Author Report Share Posted September 4, 2021 Hi @Adamw Considering the wideband is heating up for 30 seconds at start, how can you tell the car is rich? Are you looking at the wideband after it heats up? Also, is there a trick to get the wideband to not reset/heat when I crank the engine? Thanks Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 4, 2021 Report Share Posted September 4, 2021 I assumed you followed my instructions above that said to allow the wideband to warm up before starting. If it is resetting on start up then that would suggest it is wired to an ACC circuit rather than IGN. Quote Link to comment Share on other sites More sharing options...
VegasAWD Posted September 4, 2021 Author Report Share Posted September 4, 2021 5 minutes ago, Adamw said: I assumed you followed my instructions above that said to allow the wideband to warm up before starting. If it is resetting on start up then that would suggest it is wired to an ACC circuit rather than IGN. I did but I didn’t realize it actually reset itself on the crank-up and started heating up again. I’ll try and get a good startup with constant power to the wideband. Thanks. Quote Link to comment Share on other sites More sharing options...
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