This is the control head for the Sniper. Top left is the Throttle Position Sensor (TPS) – it auto resets to 0 each time you start it. Under that is the Idle Air Control (IAC) – this is what the Sniper uses to control idle speed. Coolant Temp (CTS) is in the top middle. RPM in the center and bottom center.
The right side shows the Target Air Fuel Ratio (AFR) at the top and then the actual under it. The Manifold Air Temp (MAT) next and then the lower right has the Ignition Timeing.
At wide open throttle it goes to 32-34 and while cruising it’s 15. It goes lower when it’s at idle.
It does idel much smoother with the timing control and I have the idel RPM set for 670. I love the slow rumbling roll over at that speed.
Added HyperSpark add…
First the TBI – In 2018 I put on the Holley Sniper EFI. I love it, works great. I know a lot of the Youtube Carb vs EFI run dyno test and it says there isn’t a ton of differences I think there is enough difference to more than make it worthwhile.
The throttle response is the biggest change compared to the carb – it’s almost instantaneous. And it’s smooth all the way up.
I did have a problem with it. When was coming to a stop light I would down shift and use the engine to slow me down. The Sniper leans the mixture way down if it see’s that you’re slowing down and don’t need any fuel. It leans out to pretty much no fuel.
I have two O2 sensors – the one that comes with the Sniper and i still have the Innovate sensor I put on when I was using the analog tbi and the megasquirt. I’ve got one O2 sensor on the right site and one on the left side. I do not have a crossover. The Innovate is an analog meter so it’s easy to follow what’s going on. I don’t think digital is great for this type of reading. So when I slow down in gear the mixture will drop to more than 18 to 1 – extremely lean. There’s nothing wrong with doing this – actually saves gas.
The problem is that when I get to the light if I don’t blip the throttle the engine dies – it doesn’t recover quick enough. I haven’t played with trying to get rid of the problem I just don’t use the down shifting as a brake – I use the well, brakes.
UPDATE – since I’ve added the Hyperspark, coil and discharge box it appears the problem is gone. I notice the timing quickly changes and the engine comes back to idle. I’ll need to really test it though, I’ve not driven it enough to be certain.
Enter the Hyperspark – From the beginning of my playing with efi I’ve wanted to also control the timing as well. With the Megasquirt it required putting a sensor and timing wheel on the engine so the system knew when #1 cylinder was at top dead – that’s the reference most timing control works off of. I just never got around to doing all that. Then they come out with the Hyperspark and you don’t need a timing wheel – I was convinved.
They make one for the 215 V8 (both Olds and Buick are the same) and I bought one from EFI System Pro (efisystempro.com). It was an easy setup – put the engine at TDC for #1. Check where the rotor and which wire is for #1. Put the new distributor in. While it’s still lose you put this plastic thing on in place of the distributor cap and then tighten it down. Put on the distributor cap and wires and reset the sniper control so it knows you added the Hyperspark and start the engine.
Worked first thing. And I was still using my original MSD 3 coil and my homemade electronic discharge unit.
Started it up, took it over to the expressway and was very impressed. Very quick response and it was great – drove over to the next exit. At 65-70 mph I’m doing something around 2000 rpm. It was about 12 midnight and this part of the expressway is dead. So I slowed down a bit, downshifted and punched it. It takes off, I get that wonderful feeling in the seat and then – and then – it stutters. CRAP. What the hell is that? I back off a bit and it running fine. I get on it again – it takes off and then it stutters. I figured out that it happened after 3000-3100 rpm – every time. Up till then it was great.
I could drive it fine – up to 3k – and in any gear so the problem is confined to the engine. The nice thing about the V8 is it’s perfectly driveable only going up to 3k. We took it out for drives – did a 100miler the other day without any problems other than not being able to get on it.
I thought at first it was my home made electronic discharge unit so I replaced that with an Allison that had on hand. No difference – stuters like clockwork at 3100. I had checked wiring – nothing lose and the car was reliable up to the stutter. So I figured it was the coil. I could go get a coil – or I could jump in whole hog and get the Holley coil and discharge unit that were made to fit the Sniper. And that’s what I did.
Got it in, found a place to put everything and started it up. Took it for a ride and vroom right up to 5K without a tick.
So it’s all set till I tinker with something else. Actually the next thing is to pull the dashboard and redo all the lights to LEDs. The originals suck. But while the weather is good I’m gonna drive the hell out it.