Lean and then Rich.

[Jayman1982]

Hello Everyone. I’m new here and to Holley Sniper. I'm having a problem with it getting real lean when I let off the acceleration like coming to a stop. AFR goes to 18 to 21. And if I have to slow down for some reason and I start to accelerate slowly to get back up to speed, it gets real rich. AFR goes to 10. I’ve updated ECU firmware and 3.5" TSLCD display. Has anyone had this problem before?

[andrewb70]

It's more than likely a tuning issue, not something wrong with the Sniper. Andrew

[Danny Cabral]

Overlay the datalog onto your Global Config File (GCF), and pay special attention to the center paragraph in blue print:

Originally Posted by Danny Cabral Quick Datalogger Information: Always provide data, not just symptoms. Is the AFR & ignition timing optimized? Overlay the datalog onto your Global Config File. Ensure the Target A/F Ratio table is properly programmed for your engine. Ensure the ECU is "Learning" (Learn Table LINK). Scroll through the datalog to the problem area. Then look exactly where this happens on the Base Fuel & Timing Tables. Scrutinize: RPM, MAP, MAT, TPS, CTS, IAC, Target AFR, AFR Left, CL Comp, Ignition Timing, Duty Cycle, Fuel Flow, Fuel Pressure & Battery. Using the Holley EFI software (LINK), look at where the live cursor moves to during this occurrence, and manually tune that area of the Base Fuel Table (enrich or lean) & Base Timing Table (optimize ignition timing). I find the most helpful datalog function, is overlaying the datalog on your GCF. I'm in the habit of using the datalog Overlay feature every time I review a datalog. Click on "Datalog" (on the top Toolbar), "Activate Overlay", then "Open Data Log". You can literally "playback" a recorded event, and watch it as it happened on any screen. Minimize (shrink) the datalog window, and move it to the bottom of any GCF screen. Then click & scroll anywhere on the datalog, and watch it playback on your GCF (EFI software). http://documents.holley.com/techlibr...9r10543rev.pdf (Holley EFI Datalogger Instructions) https://forums.holley.com/showthread...s-amp-Datalogs (Datalog Information - Read "NOTES") https://www.youtube.com/watch?v=iqHO...C6FEA0BB99AF17 (How To Record & Email A Datalog) https://forums.holley.com/showthread...7531#post77531 (Closed Loop Datalog Tuning - Posts # 2, # 4 & # 6) http://forums.holley.com/showthread....2523#post62523 (Read 4th & 5th Paragraphs - Smooth Fuel Graph After Transfer Learning)

[Jayman1982]

So the only way to do this is with that cable I’ll need to order and a laptop?

[Danny Cabral]

Yes, reviewing datalogs & tuning a GCF (Global Configuration File) is performed with a laptop/PC. When you have a Sniper EFI problem, it's time to buy an inexpensive used Windows laptop (to download Sniper EFI software, retrieve the GCF from ECU, engine tuning & datalogging). Pay attention when on the Holley EFI Technical Library webpage (LINK). A large red banner separates Holley's different EFI systems by name.
http://documents.holley.com/199r11031r.pdf (Holley Sniper EFI Retrieve, Save & Upload GCF - SD Card & Laptop/PC Usage, Pages 72 & 73)
https://forums.holley.com/showthread...102#post231102 (Related Forum Thread)