Saturday, January 31, 2026

Holley Sniper Stealth EFI - Part 14 (Start-Up)

This morning, I performed the start-up process as defined in the Sniper manual.  The steps primarily consist of using the Wizard to define some variables, confirming your throttle position sensor is reading properly (0 to 102% in my case), and checking for leaks.  When that is complete, you cycle power and then are ready to start the engine.
This is the point where you always hesitate just a little and start to think over everything that you just checked to make sure you feel good before turning the key.  I turned the key and it took between two and three seconds and the engine started.  It ran rather smooth and with the outside temp so low the coolant temp was at an initial 69 degrees.  The engine would not start to learn until it reached operating temperature of 180.

When the engine first started the idle was close to 1,200 RPM (set to decrease to 850 when warm).  As the engine began to warm up, the RPM increased a little and was closer to 1,600.  The AFR was initially around 12.5 at start up but slowly increased to where it was rather lean.  The average was probably around 15.5 but there were points it would spike much higher.  

The entire time the car was getting to temperature, the CL Status was OpenLP and it doesn't start learning until that states ClosedLP and the temp is above 180.  The temperature ultimately reached 186 but the CL Status didn't change to closed.  The idle also stayed at 1,600.  The AFR stayed rather high too and when I captured a few pictures it showed 16.8, 18.8, 16.6, and 17.1 (it was obviously changing rapidly so I took a few quick pictures in succession).

After letting the vehicle idle for a while at 1,600 RPM and above 180, I decided it wasn't going to switch to learn mode and turned the car off.  After researching it a little, I found that I need to adjust down the idle setting in order to get tuning to begin as my idle was too high for that to start.  I adjusted out the idle screen by a half turn, started the car, and it was still warm enough that it went straight to ClosedLP.  

I drove a couple of miles without any issue and came home.  For reference, the mileage at the point of installation was 8,535.  I was still running on only 3 or 3.5 gallons in the tank so I didn't want to have any problems.  I'll fill it up with more gas and then go for another ride later.  So far, I've been into 3rd gear, mostly slow, but at one point up to 4,000 RPM.  The only issue I've noticed is when I let off the gas, the RPM does not drop as quickly as I expect.  

I think I still need to adjust the IAC too.  I just put it in the ball park and the car started and began learning.  The idle is still always at 1,100 or so when I'm at a stop when it is set to target 850.



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