ECMlink 2G Cold idle surge

[jesse12345]

I've got a very weird idle surge even when I first start the car in my 70 degree garage. I have ECMLink on speed density and no FIAV just running an IAC. When the car us fully warm it idles rock solid and everything checks out great.

I've checked up and down for leaks and I have zero. This issue came about after I added the IAC because before I had everything blocked off and it idled very good. Is this something I'm just going to have to live with?

I have everything just about as stock in ECMLink as I can make it. My whole setup is stock aside from 550cc injectors and 5 bar map sensor. I don't see how adding the IAC to the throttle body would make it worse so I'm a little confused. I can post a log if it helps.

I'm stupid and didn't post this in the right section so if one of the mods could that would be great. That was my bad.

Here is a cold to hot idle log.

 

[steve]

I didn't see any actual idle surging just it hunting with the ISC.
What happens if you disconnect the ISC connector?

It's been awhile since I've done a set of RC550's but +400ms seems like a lot of extra deadtime.
I can't comment on the tune, SD isn't my thing, nor atmospheric BOV's.

 

[jesse12345]

Disconnecting changes nothing. Its brand new but that doesn't really mean much. I thought 400ms seemed like alot to but that's where everything seemed to be happy. My combined ft was way off when I had it at say 200ms and the idle wouldn't stay steady when fully warm. Before I even added the isc back the idle was great, no surge or hunting when it was cold or hot.

 

[steve]

Correct fueling depends on correct airflow and injector values. With Speed Density your airflow depends on several parameters but the most significant one is the VE Map and if it's not correct playing with fuel parameters can make things like AFR and idle look correct but cause other issues.

Since disconnecting the ISC connector doesn't resolve the idle hunting I'd suggest it's not because of the ISC. Since you don't have cams or other aftermarket changes your Airflow/Rev should follow the normal values at various RPM's. If they don't I would suspect the VE Map first and once it's accurate work on the injector fueling parameters of the global and deadtime. But like I said earlier I don't care for SD much when I can work with calibrated MAFs and sealed intakes.

Hopefully the guys that do spend more time in the DSM SD tuning will provide some solid feedback.

 

[jesse12345]

I appreciate the reply. I guess I just reset the ve table and I haven't touched it. I wasn't real sure on what to do there.

 

[Tiki2777]

I know you mentioned you've checked for leaks, BUT.....it may be worth visiting/revisiting HOW you're checking for leaks, especially in the typical DSM trouble areas (TB, IC pipes, BOV, IM, etc etc). Speed Density will help bandaid the air leaks but if your tune isn't refined, it's going to give you weird issues such as yours.

 

[jesse12345]

So far I've triple checked all of that. Last summer I put new throttle body seals in along with new gaskets.
I just find it weird how I went from a throttle body block off to a bypass and now with an isc I get a weird idle. With no isc my idle was really good. Should I go back to blocking it off and see what it does? I'm pretty much stock aside from speed density and injectors of course. The idle hunting when cold just drives me crazy. I just want to get to the bottom of this.

 

[Justin DuBois]

So far I've triple checked all of that. Last summer I put new throttle body seals in along with new gaskets.
I just find it weird how I went from a throttle body block off to a bypass and now with an isc I get a weird idle. With no isc my idle was really good. Should I go back to blocking it off and see what it does? I'm pretty much stock aside from speed density and injectors of course. The idle hunting when cold just drives me crazy. I just want to get to the bottom of this.

I have a FIAV, and when the coolant is low, it won't close down and it will idle surge. Idle surge is aggressive, cuts ignition to prevent runaway over 2000 rpm.

As mentioned, you look like you have some idle hunting. In your DA setup, I'm not sure giving the IAT more weight over the coolant temp is helping. Re-test for boost/vac leaks - and work on your global dead times to reduce your fuel trims when you are all heated up between 190-205 deg.

 

[pauleyman]

I have a FIAV, and when the coolant is low, it won't close down and it will idle surge. Idle surge is aggressive, cuts ignition to prevent runaway over 2000 rpm.

This is the one thing I just dont know why we still talk about. If any car is in closed loop and maintains an idle over 1500rpm then at a bare minimum, either ECU doesnt know throttle is closed or the throttle isn't really closed.
I know you know this but for 30 years we've been talking about it as a group.

As mentioned, you look like you have some idle hunting. In your DA setup, I'm not sure giving the IAT more weight over the coolant temp is helping. Re-test for boost/vac leaks - and work on your global dead times to reduce your fuel trims when you are all heated up between 190-205 deg.

 

[jesse12345]

Doesn't the fuel look good when it's warmed up? Should i reset deadtimes at all? I'll check for leaks again. I put in a new biss o ring and all. I'll give it another peek though it doesn't hurt. I've been very meticulous on everything I've been doing. I just hope the tune is at least in the right direction. I'm guessing it has to do with speed density because when I was on my maf it ran absolutely flawless even before I dialed in the injectors.

 

[Justin DuBois]

Doesn't the fuel look good when it's warmed up? Should i reset deadtimes at all? I'll check for leaks again. I put in a new biss o ring and all. I'll give it another peek though it doesn't hurt. I've been very meticulous on everything I've been doing. I just hope the tune is at least in the right direction. I'm guessing it has to do with speed density because when I was on my maf it ran absolutely flawless even before I dialed in the injectors.

The fuel trims are not bad really - warm they show an average of 0.4 - so global dead time can stay where it is. SD idle can be fussy. Can you get the RPM's to drop - try targeting 800 rpm

Your TPS sensor is showing 0.67v closed, sometimes reporting 1% - Maybe adjust your TPS to 0.63v closed.

I would move on to WOT at 5000 RPM and see where your AFR's end up in a 3rd gear pull so you can see if you are hitting targets at your low boost setting.

Once you confirm Global Fuel with WOT is calibrated, then you can go back to working on idle and cruse. The automatic SD VE adjust (Combined FT) function will give you suggested VE changes when you have a good cruise log to pull data from.

 

[jesse12345]

Okay ill adjust that. It's probably going to be awhile to rip the car wide open since it's winter currently. I was just hoping to dial in the tune a little nicer for spring, but no big deal. I just wanted the pros to see how the idle tune looks so far since that cold idle is so shaky. I appreciate all the help so far. You guys rock!

 

[jed344]

Ok so I will do a quick rundown.
When in the Direct Access area of ECMLink this is what is changed.

Air flow smoothing at 0hz to 800hz. Increased from 87.9 to 91.4. I doubt this is your issue.

FastIdleATISCPos is modified when AC is off. Your profile lead's me to believe this is a auto car so this table does play a role here. This table for auto or for manual adds ISC position based off coolant temp I have found. This is useful when there is no FIAV and the car has large cams, e85 ect. This will then add more ISC position to increase idle at XXX coolant temp to do the same thing as the FIAV stock.
Stock 2g value for auto is -2 F 60, 19F 60, 46F 60, 70F 60, 95F 60, 126F 48, 176F 26, 190F 20. Yours vs stock has more at warm idle, Less during warm up.

InjBatteryAdj is modified but without having a sheet for your injectors i cannot say if it is wrong.

SDTempWeighting is modified. This table effect's how much coolant temp VS intake temp effect's the calculation. 1 coolant temp ignored, 0 intake temp ignored.
0 to 1200 is modified vs stock. Stock 0 .25, 400 .25, 800 .30, 1200 .35. You are weighting heavier on coolant temp vs intake temp in these area's.

Everything else is stock untouched in DA.

Live config.

TPS -6 and 116% scale. I generally adjust TPS manually so I get within 3 and 107% per say after confirming my cable is fully opening and closing the TB. This way I know I am getting full range of throttle body to start. Usually ends up .59-.65V with full range and then the little more I just adjust in link control. .63V and 0% and 5v and 100% is the goal.

Coasting FC offset. This essentially tells ECU when to turn back on injector pulse when motor is revving down. This assumes 700-750rpm when this value is stock for idle. If you want to idle at 950 rpm this should be set to 190. I have found this does not really effect very mild car's, but when something is say 10:1, e85, S3 cams ect. This being wrong will cause stalling often as it does not start injecting fuel back till too late.

Fuel tab.

Fuel cut is at 19 psi boost and that's fine, or load factor 2.65. Very low load factor value but not my call or is it causing your issue. Just pointing things out.

Global fuel is set so we hit target air fuel at peak TQ. 4500-5000rpm in SD table at 100% for your car. Your target air fuel is stock so 9:6. This is one area people often do get wrong. We build the openloopmaxoctane table so our target is the air fuel ratio we want. Then set global so at peak TQ and 100 VE we line up. You can have your target at stock 9:6 and then adjust global so you hit 11.1 but your tune is still WAY off then. This is how air flow calculation. LB/MIN ends up way off. When you set the target right, then have global right so at 100 VE it hits target this show's the ECU's assumption of VE is correct. Make's the lb/min line up VERY closely with power the car make's on the dyno backing up the ECU's calculation is right.

I see Idle air clamp is turned on. This generally is for when using a vented BOV with a stock MAS. No values are modified and I am not sure if this would even effect anything when using SD operation but either way is not needed on.

Boost table just targeting WSG pressure fine.

MISC.

If the car starts just fine when warm then no worry's here. The hot start enrichment is turned off and usually I only have to touch that with certain e85 cars, but if yours starts fine warm then leave it. Stock is this on.

I see fans full on checked? This mean's the fan's will run full on all the time. Nothing wrong per say with this but sometimes I have found certain set up's the fan running all the time restricts air flow at speeds vs it turning off. Still not a concern for your issue.

I see when it's warm things look quite good. Airflow per rev is fine, fuel trims fine, ISC position is a hair high but not really bad.
I would make sure your TPS is correct as it is a bit off and also be sure of throttle cable tension.
Your front O2 is quite active but that table was not touched so long as its in factory position then that's ok.
Long term learned idle ADJ starts at 132 and creeps up to 147 by the end.

I would say get TPS right and maybe set the fast idle auto table back to stock may correct the idle hunting when cold.

 

[jesse12345]

Thanks a ton for the detailed breakdown. I think some of that I changed to see if it would make a difference to my cold idle. It did not so I can set it all back to stock if you think I should. I'll adjust the tps first and see what it's like. My bov is actually not vented but there is no maf so I'm guessing it really doesn't matter.

 

[Stapl3]

As an experiment, try doing this to the table.

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[jesse12345]

Alright I got the tps literally as good as I could get it but it loves to hop from .63 to .67 still. I also tried 5 degree of timing and maybe that helped but I'm not sure since I put everything else back to stock. It's a whole lot better now it'll hunt every once in awhile but it seems to be way better.

 

[Justin DuBois]

This is a modified EVO8 timing table for E85, but you can see in the low RPM, 1000 is set to 5deg.

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[jesse12345]

Is the stock 2g timing to aggressive at idle? I did let the car cool all the way down and I started it again and it'll still hunt but not nearly as long as it did before. I think things are getting better but maybe it's just in my head I'm not sure.

 

[jed344]

Is the stock 2g timing to aggressive at idle? I did let the car cool all the way down and I started it again and it'll still hunt but not nearly as long as it did before. I think things are getting better but maybe it's just in my head I'm not sure.

The stock table is not per say aggressive at idle. Why they said to try that is because you have your idle rpm set higher it may jump into next cell up. When there is timing advance in that cell it creates more engine tq. That causes the engine to rev up and i have seen that for sure it can ride a timing ramp up causing the car to idle up higher then wanted.

I always make the idle area the same number so it does not accidentally ride a timing ramp up. Example on a 10:1 e85 s3 cam car with idle set at 1,100rpm. When the hole area it will idle is set at the same number it stays steady. I often even have them idle at 8-12 degrees as it helps, but its the same number. If i had the car go from say 5-8-12+ every step it could hit there then the increasing tq can cause it to idle up. The same number does not cause it to ramp up.

Anyone who has played with a distributor has seen this. When you turn it at idle they often will idle up or down as you advance or retard the timing. Still same air flow. This is just how timing advance works.

 

[jesse12345]

Okay that makes more sense. I forgot I have the idle set higher. Should I lower that to 750 or 800? Would that possibly help things? Lowering the timing definitely helped it. The hunt is still there but not nearly as bad and not for nearly as long as before.

 

[jed344]

Okay that makes more sense. I forgot I have the idle set higher. Should I lower that to 750 or 800? Would that possibly help things? Lowering the timing definitely helped it. The hunt is still there but not nearly as bad and not for nearly as long as before.

Personally if the car is mostly stock and stock cam's i set it at 750 sometimes 800. Only time i go higher is when the set up requires it as the car will not happily idle at that low of a rpm.

With more extreme cases if have extra fuel and ISC offset so the car idle's much higher say 1500-1800rpm during warm up and then comes down to my target at warm idle. This though is honestly just for extreme examples. You should not need extra rpm during warm up.

Now if say its 20 degrees you likely will need more idle rpm but that is done with ISC offset based off coolant so it does what the FIAV used to do. Sometimes more fuel too based off coolant temp.

My own 10:1 e85 car with s2 cam's at even just 40 degrees has 10%+ fuel and over 2k rpm worth of isc added so it run's. Always better off to get it fired and warming up vs cranking and washing down cylinders with e85.

 

[jesse12345]

Awesome thank you for all this help. This car is just about as stock as can be. I'm still learning everyday so I appreciate all the professionals taking the time to help a guy out.