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Bad idle after tune installation

Diocletian

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Been there, had that. It's still there but very very faint now. I notice it but maybe I'm just...
Mine was idle on brake. It would bounce ~500 - 1000 rpm. I thought for a moment that it could be a vacuum leak but it was after tuning.
Yep that's the issue we are all getting. Mine got worse over time until I went back to 93, then it stopped completely. So you're saying yours just...went away?
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Zinc03svt

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That is crazy to my 1800 mile experience. Be happy to record any driving, idle, etc. my E85 tune. What do you want to see?
 

Bahndvr

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Yep that's the issue we are all getting. Mine got worse over time until I went back to 93, then it stopped completely. So you're saying yours just...went away?
No, I had Lund look at a datalog and they saw it so they revised my tune.
 

kris5597

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So to shed some light on this older thread, my car continued with bad idle, no matter what I did in the calibration to correct it until the car started dying completely. Then I had another issue, my HPFP would not push fuel pressure over 900psi, this is a recent finding. Took the dealership, HPFP failure, had to replace the pump. That was causing the idle issue and WOT fuel starvation.

Kris
 

kris5597

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Update... the fuel pump replacement did not fix either issue. The pump proved to be faulty, but something else is causing these issues. Car is going back to the dealer tomorrow for further diagnostics. At this point, I feel it is something more serious in the PCM or something along these lines. Something has failed and there is nothing pointing to the issue. I reviewed my calibration, looking through everything that was changed when I tuned the car, even resorting back to the stock calibration for further troubleshooting. Nothing has fixed nor help the cause come to light. We will continue to investigate.

I'd like this noted for anyone who experiences either issue that I am.

Kris
 

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Zinc03svt

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That is crazy Kris and hope you get it sorted out. I started and ran mine yesterday in 30 degree air on full E with zero issues.
 

kris5597

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Still fighting the erratic idle, cannot find anything that points to the issue. Let the car idle in park/ neutral, no issues. Only comes when the car is in drive and stopped with the foot on the brake. The idle will dip slightly then it will start bucking real bad. During this, fuel trims, ignition advance, and VCT all goes wack. I can sit at idle and watch the cams slowly start changing, then go to zero, idle goes ham and then bam back to normal. Trying to figure out why the VCT starts changing at idle. I'm about to go super in depth in the mapped point VCT targets and start reconfiguring to determine the issue.

Kris
 

suprmario96

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Still fighting the erratic idle, cannot find anything that points to the issue. Let the car idle in park/ neutral, no issues. Only comes when the car is in drive and stopped with the foot on the brake. The idle will dip slightly then it will start bucking real bad. During this, fuel trims, ignition advance, and VCT all goes wack. I can sit at idle and watch the cams slowly start changing, then go to zero, idle goes ham and then bam back to normal. Trying to figure out why the VCT starts changing at idle. I'm about to go super in depth in the mapped point VCT targets and start reconfiguring to determine the issue.

Kris
is it possible the brake booster diaphragm has a leak in it?
 
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I just wanted to add to this thread. I have this same idle surging issue on my 20 GT A10 with a Flex Tune from ID Motorsports (so it’s not just Lund) when running E85 or E blends. If I flash to stock or any straight pump gas tune, the issue goes away. So it’s definitely something to do with Flex Tunes in general and maybe something unique about certain cars.
 

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GeneraL

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I just wanted to add to this thread. I have this same idle surging issue on my 20 GT A10 with a Flex Tune from ID Motorsports (so it’s not just Lund) when running E85 or E blends. If I flash to stock or any straight pump gas tune, the issue goes away. So it’s definitely something to do with Flex Tunes in general and maybe something unique about certain cars.
Yeah same happens to me with palm beach dyno it only happens when I run e85.
 

carguy231

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I'm having a heck of a time with my EB 50-state tune. On LiveLink, it looks like the throttle body angle is off on the 'absolute'. Got a replacement from EB and it was good for one day, then the next day did it again - stall or almost stall on cold start. And the idle at lights is becoming erratic. I HATE throwing parts at an issue, but I ordered a new MAF. My filter fell off, and I cleaned the MAF carefully, but maybe... We will see.
 

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I don't think it's the tune. The tune is just pronouncing an underlying issue that is already present. I tried to get Lund to help me troubleshoot the issue but he didn't want to troubleshoot an issue that is not caused by his tune. I was not blaming his tune, I just wanted to isolate the issue. On the stock tune I noticed a slight dip in idle but recovered very quickly so I knew something was happening but ignored it.
If someone were to ask me what is the culprit, I'd say it's something in the Traction Management System.
 
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Hello everyone having the same issues with my flex and e85 PBD tunes. Anyone having crazy LTFT’s and or codes thrown?
 

carguy231

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It's not the tune. I have a mechanic friend whose son's bone-stock 17 GT PP is also getting an intermittent weird idle at traffic lights as well. I don't see how it can be Traction Management when
1. It happens on startup
2. It happens sitting still at a light, even in Track Mode.

What could be causing it? No CEL, no codes thrown. Still making great power on the dyno.
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