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ECMlink Random No-Idle issue

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CrackedDSM

10+ Year Contributor
3,869
3,150
Dec 17, 2009
Pensacola, Florida
Hey guys, I've been asking for help in my build thread but so far no dice.


Problem: Random no-idle situation, and slight hesitation/misfire.

Explanation: Upon first start-up/cold start, it has the tiniest hint of a misfire and stumble from 1.5-2k. Above and below that is fine, throttle response is fine above and below that as well. It will also refuse to idle on its own sometimes, seemingly at random. If I start it, let it struggle, turn it off and let it sit, it seems like after the residual heat heats things up, it'll start and idle fine. Rev fine, no misfire, etc.

The thing that gets me is its intermittent. It's not steady or constant at all. I'm gonna post an idle log so you can see what I mean, the car will idle on its own just fine sometimes.

Setup: I have a build thread that's up to date, but basically 2G MAF, FP Green, ETS Short Route intercooler, BC 272 cams, BOV recirculated, OEM 1G intake manifold, FIC 1050's.

One day I adjusted the Coasting FCoffset, and that seemed to help it a lot. But a few days later(today) now it's back to doing what it did before.

Please help. Lol.
 

Attachments

  • log.2024.05.27-01.elg
    277.7 KB · Views: 7
Changed a few things based on advice. Still to date only one person even looked at these logs and tried to help at all. Kinda makes me sad. This thing hates trying to idle at all. I don't know what if anything is going wrong or what's making this thing hate life suddenly. Is my ECU dying, is the ISC taking a shit, is there some smoking gun that I'm missing that's obvious?
 

Attachments

  • log.2024.05.29-02.elg
    562.1 KB · Views: 8
It's kinda rich but otherwise looks good to me.


Yeah, that's also a sudden development. I didn't add fuel anywhere. In fact I took about 10% out in the MAFcomp for 50 and 100hz. It's telling me pretty much I should take 10% out everywhere. I added deadtime, but didn't think it would increase fuel that much.


IDK. If the tune looks fine then it's something mechanical. But I have zero clue on what mechanically could cause a random no idle and random perfect idle issue. ECU driver dying?


Follow up question: Would adjusting the BISS screw really make that much of a difference? The ISCposition is kinda high I think.
 
Your log shows 10% taken at 500hz which occurs at, well, you never cross 300hz. It's why I asked how you arrived to that adjustment.


I did all those from 500-1000hz on a previous log(few days ago when it was idling like a champ and I thought it was fixed) because the tool recommended it. IT was pegging rich(9.9:1, lowest the AEM WB would read) at like 8-13lbs(wastegate pressure's max) so I took fuel out. That helped a ton up top.


I swear on God I adjusted the MAFcomp -5% at 50hz and 100hz just now. I hit save and everything. Weird.



So...is my ECMLink just not flashing like it should? Because there are other changes I made to the tune not saved/not shown on that log.
 
There isn't a 5% adjustment.
I recommend you zero out the sliders and calibrate the fuel system. You want the slider at peak VE to be zero and you're already away from that. This is not the path.


Copy. I’ll do that. Sadly I can’t do anymore today because almost woke the kiddo this last time playing with it. But I’m making a list.
 
I can't speak much for your tune, but I noticed much better cold idle after I hooked up the OEM fuel pressure regulator solenoid inline with the AFPR boost source and making the appropriate change in link. It helps increase base fuel pressure under vacuum situations.
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I think you're still running a MAF so shouldn't your pin assignments be set to 'undefined?' Also is your wideband installed in the front o2 location and simulating NB? If not, that one should also be set to 'undefined' as well.

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I can't speak much for your tune, but I noticed much better cold idle after I hooked up the OEM fuel pressure regulator solenoid inline with the AFPR boost source and making the appropriate change in link. It helps increase base fuel pressure under vacuum situations.
You must be logged in to view this image or video.


I think you're still running a MAF so shouldn't your pin assignments be set to 'undefined?' Also is your wideband installed in the front o2 location and simulating NB? If not, that one should also be set to 'undefined' as well.

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Wideband is downstream in a separate bung, front o2 sensor is new and OEM and working. I don’t think those inputs affect anything but if someone can prove otherwise I’ll change them for sure. This map was originally SD from RIX Racing for another customer so I’m still finding weird settings I have to change.
 
Maybe they don't do anything but what good does it do to set an option that doesn't physically exist? My theory is to set as much as possible back to stock, hopefully to make it run proper, then tweak your settings and monitor the result.

It's not hard to revert to a previous configuration as long as you save your logs.
 
Maybe they don't do anything but what good does it do to set an option that doesn't physically exist? My theory is to set as much as possible back to stock, hopefully to make it run proper, then tweak your settings and monitor the result.

It's not hard to revert to a previous configuration as long as you save your logs.


For sure! I'll change 'em back and see what it changes. Hopefully a lot.

I'm also gonna mess with the BISS screw to get the ISC to read 30-40's when warm. Hopefully that helps. I was thinking about what, if anything, I changed in the time between the perfect idle I had and now, is the BISS. So between the two, hopefully that fixes it. I'd really like to move on and start tuning it for cruising and WOT/performance. I don't wanna get greedy on the unbroken-in clutch yet, but man I need more than 9-12lbs.
 
Changed all the MAP and narrowband sim to undefined, and it didn't really change much.

Calibrated fuel system to fuel pressure and injector sizes. Helped up top and at WOT, but 0-100hz was hot garbage. Would lean misfire, and refuse to idle. Had to add 20% to mafcomp in those areas. OMG

But the hugest help, was completely closing the BISS, and adjusting it 2.5 turns out. That allowed it to idle a little, and then adjusting it slowly from there until ECMLink read 33-40ish on the ISCposition solved the idle entirely. So that was the fix.


(I did these things in reverse order listed, so the BISS was done first and it fixed the idle)

Log posted in my build thread. Don't wanna post it here because I don't wanna have to explain everything again. :p
 
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