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401 Sniper EFI AF/R

Posted: Fri Nov 30, 2018 1:01 pm
by FSBOB
Hi all,
I've recently rebuilt my 401 and have been trying to get my fuel injection dialed in better. I've been running the stock settings that came with the Holley system since I installed it. I know it's been running rich and want to get it set where it's running better without endangering the engine. What have you guys been running as far as air fuel ratio in your rigs? I'm currently set at 13.7 at idle, 14.2 at cruise, and 12.7 at WOT. Thanks for your contributions.

Re: 401 Sniper EFI AF/R

Posted: Wed Dec 05, 2018 4:29 pm
by az chip
I would answer but have not got down to that point in tuning yet. Although idle seems fine and cruise looks like mine on my 360.

Re: 401 Sniper EFI AF/R

Posted: Sat Dec 08, 2018 2:16 pm
by KJ Ryu
It shouldn't be running rich with those settings. My guess is that, like me, you got a defective O2 sensor. My original died a couple of months after installing EFI.

Re: 401 Sniper EFI AF/R

Posted: Sun Dec 09, 2018 12:47 am
by az chip
KJ Ryu wrote:It shouldn't be running rich with those settings. My guess is that, like me, you got a defective O2 sensor. My original died a couple of months after installing EFI.
I think they all die from excessive fuel washing over them on initial set up.

Re: 401 Sniper EFI AF/R

Posted: Sun Dec 09, 2018 1:42 pm
by babywag
FSBOB wrote:Hi all,
I've recently rebuilt my 401 and have been trying to get my fuel injection dialed in better. I've been running the stock settings that came with the Holley system since I installed it. I know it's been running rich and want to get it set where it's running better without endangering the engine. What have you guys been running as far as air fuel ratio in your rigs? I'm currently set at 13.7 at idle, 14.2 at cruise, and 12.7 at WOT. Thanks for your contributions.
13.7 @ idle is way too rich IMHO
14.2 @ cruise is ok-ish but still little rich
12.7 @ WOT is fine

I'd bump both idle & cruise up like 14.3 and 14.5
Only way you'll "hurt" the engine is if you go way lean for an extended time period.

Re: 401 Sniper EFI AF/R

Posted: Tue Dec 11, 2018 11:16 pm
by Renodemona
I have the GoEFI, but my numbers are similar though usually around 14.5 cruising around, 14 or so idle.

Re: 401 Sniper EFI AF/R

Posted: Sat Jul 20, 2019 7:47 pm
by Jeepin87
401, stock low comp engine, performer intake, .480/224* @.050 cam
Idle 13.8
Cruise 14.7
WOT 12.6

I haven't fine tuned yet but it runs really well. I can't go leaner at idle or it stalls out when I put it in gear.

Re: 401 Sniper EFI AF/R

Posted: Sun Jul 21, 2019 12:26 pm
by babywag
iac needs adjustment or isn't working properly if it stalls from park to drive

Re: 401 Sniper EFI AF/R

Posted: Fri Aug 16, 2019 4:10 pm
by Jeepin87
babywag wrote:iac needs adjustment or isn't working properly if it stalls from park to drive

Nope, IAC is perfect (at least the numbers I'm seeing). I don't carry as much vacuum as most flat landers and my cam is a little hotter than most run in their FSJs (although it is NOT considered a hot cam).

With that being said all of my 401 rigs have liked to run a little rich at idle. The 360s and 6cyls have been happy with a leaner mix though.


Edit:
You have a SNIPER system on a rig in Cali? How did you pass the visual?

Re: 401 Sniper EFI AF/R

Posted: Tue Nov 23, 2021 7:03 pm
by Moosehead
Just upgraded EFI from a buggy FAST unit to the Holley Sniper on a 401. Very pleased with the Sniper thus far and its built-in fuel pressure regulator, and cleaner setup. Unit looks and feels way more robust, and Waggy is running really nicely.

I also adjusted AFR stock settings mentioned in OP closer to BabyWags suggestions, and took down idle RPM to 750. The old girl purrs until giving her throttle and MPG’s are closer to 10 rather than 8.5.

Have considered going to the progressive link to sequence the primary and secondary throttle butterflies, but she is so fun to wheel around as is. Other drivers genuinely seem surprised when being passed by the Wag.

Much appreciate the knowledge shared above and on other Holley Sniper threads.


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