Sniper Cold Wx Tuning - Any tips? (1 Viewer)

[zerotreedelta]

The Sniper was happy as a clam while the weather was warmer, but it wants to stumble on acceleration with these cooler fall days (30-50* out). It seems like it's some tweaking required in the coolant temp and/or air temp compensation, but it's slow going to tune it as you get one shot a day when it's cold. Past that off-idle accel hiccup, it starts and runs fine.

I'm not losing too much sleep, as it's getting stashed for the winter shortly once the road salt flies, but thought I'd see if any of you in the colder areas have found some tweaks that worked. Letting it warm up until the coolant gets to 125 or so is enough for it to be pretty happy, which doesn't take all that long...but shouldn't need to, either.

Anyone run into that and find any good compensation factors?

 

[zerotreedelta]

Updating the thread a bit - I think I found the issue, and it's not what I'd have thought...but it explains why fiddling with the air-temp tables wasn't helping.

I'd had a slight exhaust leak that I could hear after startup, but would go away once warm in typical exhaust-leak fashion. It was very minor, and I'd had the downpipe off a few times, so I'd assumed it was that donut leaking...I have a replacement but didn't swap it in yet. I couldn't quite pinpoint the leak, though, until the other day. After digging with the mechanics stethoscope, it just so happened that the #1 cylinder was leaking to the front, despite a flat manifold and a thick remflex gasket.

So...that leak was puffing away into that heat riser that runs up into the air filter, which is open until heat closes the flapper. My IAT temps always read higher than ambient, but I figured it was correctly happening from heat from that riser. I fixed that leak, and now IAT is more in line with actual temps and it's much much happier when it's cold. I'm pretty sure it was a combination of the exhaust leak heat throwing off the IAT as well as slightly offsetting the air with exhaust (throwing off the air/mix) - and it just so happened that it wasn't a coolant temp/mixture thing, but likely just that the intake flap would close off that riser once it got warm enough and "fix the glitch".

Who'd have guessed.