I've searched through the forums and haven't been able to fix my issue. Vid link here:
Relevant mods are AEM v2, ID1300x2 injectors, SoS Flex Fuel sensor. Pump E85 at 66% content.

The surge doesn't happen on 93oct, nor does it happen on a cold start with E85. In fact the cold start is incredibly smooth. It seems strictly limited to a hot start on pump E85. I've continued trial/error testing in the tune including a straight 0 seconds of start time. Mechanically, I haven't been able to find any evidence of vacuum leaks and I went ahead and disassembled/cleaned the IAC valve just in case. As an aside, I've already adjusted a bit more fuel into the hot start so it's not as lean on startup, but it was only a little bit and didn't appear to impact the weird surge.

Any ideas or recommendations? Any other information I can provide to help out?

 

Any luck solving this?

 

Not yet. I adjusted low idle settings and fixed fueling so those aren't a problem. It's perfectly repeatable but so far I haven't found the cause. Cold start is flawless which is why it's so weird.

 

I ask because I had a similar issue with my eManage back in the day.


Once I learnt to tune I had realized it was a hot-restart misfire caused by a lean mixture. Your WB wasn't really visible however once you pan back to it seems to read normal-ish but then very lean. Would like to see AFR behavior/gauge during that surge.

We want at least stoich or preferably 12-13AFR for 5-10 seconds after start and before LAMBDA feedback takes over and it settles into stoich.

I know you had said you fixed your fueling but under the 'Start' tab or whatever older AEM call it, try to see if you can fatten-up that post-start table.

If you can setups a live screenshare, or capture a datalog. Happy to take a look, or assess the data together.

Edit: We can also take a look at the 'Idle' tab to see if your idle control system (PID), specifically the (P) proportional is isolating and chasing an error too aggressively. Logs or AEM's graph charts could/should confirm.

 

Sorry, not ignoring but holidays plus family and work haven't given me time to drive it recently. I made a few changes based on your lean theory for immediate startup buy extending the start duration time at higher temperatures and adding in fuel on the flex start setting. Once I get a chance to drive it, I'll report back.

 

All right, finally got a chance to drive it yesterday and test. The first shot are the idle settings in the AEM Series 2 that are shown in the video. The second image are what I tried out yesterday which didn't impact the cycling issue. I can screenshot anything else in the tune file, but at this point I'm stumped.
Edit: I had a 'warm' start around 150F and the magnitude of the cycling was less prevalent but still present.

 

Closing the thread since I could only find a bit of a bandaid. AFRs and ignition timing are fine, i just took the Idle Surge Time down to a couple seconds. Sounds like it's trying to cycle but without the Surge timing it just settles into regular idle quickly and it's smooth from there.