Full Size Jeep Network

First off, once up to temp, my system runs flawlessly.

On cold start, no real issues other than the initial first drop (2-3 seconds) after turning over will cause the system to go lean just for a second, but it will catch itself and go back to a richer state as it warms up, eventually reaching target AFR.

If I go out for a drive with the engine cold, releasing throttle will usually cause things to go back to a momentary lean state as it returns to idle, then the system will catch itself and go back to normal AFRs. As it continues to warm, this gets to be less and less of an occurrence. Once up to moderate temp (+140 or so) no real issues. Over 160 all issues are gone.

Have any of you fine tuned the Sniper system to run better when cold? From reading things out there, it seems most of this can be tuned via the Coolant Enrichment Table. I have never tuned an EFI system via software. Just some basic tuning on the 3.5" LCD screen.

I guess maybe the easiest answer is to go out and grab a couple data logs and send them over to Holley? But I would like to learn what is happening and how to correct it at the same time.

Any thoughts?

I wonder if it is normal. Lean running will make the engine warm faster. Of course in general you don't want a lean mixture under load, but maybe under no load situations it is beneficial to warm engine up faster.

Not sure. I am getting a usb sd card reader today and will grab a couple of data logs and send them to Holley. Also need them to possibly tune it for the progressive linkage. I assume it is getting too much fuel at less than 40% throttle, since the tune is based on both butterflies opening at the same time.

You have to reset the tune when you install the progressive linkage. Should have been instructions with the linkage.

Here's the instructions I used: https://www.efisystempro.com/image/cata ... ctions.pdf

Thanks. That is what I used as well when I installed mine. I have also gone in and edited my AE Correction vs. TPS to match this graph:

https://forums.holley.com/showthread.ph ... tter/page9

Post #88

Also, this was helpful in explaining a bit for me:

https://www.youtube.com/watch?v=ap2tdGnrmxw

I moved my graph up a bit closer to 40 before the fuel starts coming in heavier. My secondaries come in around 48. Have had a couple drives so far and it seems to run a bit better. Although I am still looking for someone to help me fine tune my particular system and fuel map and then limit the learning after that.

I haven't gone beyond the basic tuning on mine. Too many exhaust leaks, and now the torque converter is rattling something fierce, so it isn't even being driven.

Betty, did you ever get the cold tuning figured out? I’m having a similar outcome with a new Sniper in a 401. She otherwise is running great. Have adjusted idle, and FAR across the spectrum, but have yet to do the progressive link.

Chris from EFI System Pro had the best start up tune explanations in below attachment, which also break it down from both handheld adjustments and software. Chris also reduces the pucker factor quite a bit. The handheld was sufficient for this noob but still allowed small tweaks in IAC Park, IAC Hold, and IAC Decay times to help with Cold Start challenges.

https://www.efisystempro.com/efi-pro-ha ... -x-stealth

Below are the basic handheld adjustments that have improved my cold starts significantly down to 20F, have not seen lower temps yet. Previously, cold starts below 50F would stall out without a blip of right pedal, or experience stall outs upon shifting into gear when cold. I have yet to download Holley software to laptop or grab any datalogs, will get there eventually.

As EFI Pro clearly notes, all engines are different, but posting these for directional help.

1) IAC Starup hold time increased from 4 to 5 seconds
2) IAC Starup decay time increased from 4 to 5 seconds
3) IAC Park increased 5-7 squares above 75%, and increased squares 8-9 above 50% (lower temps) vs default graph
4) Fuel Prime decreased from 150% to 100% (goal to maintain quick warm starts per EFI guide)
5) Fuel Prime Multiplier increased from 5X to 7X (may tweak down to 6 or 6.5X)