Turn ignition off = engine burps! Help explain!
Interesting phenomena I've experienced lately and am wondering if anyone knows what may be causing this:
Everytime I switch off the engine, 2-3 seconds later, I can hear a faint (for the lack of a better word) burp or fart coming out the exhaust.
It almost sounds like a flame is being put out and there's a soft back-fire out the exhaust.
Anyone know what can be causing this?
Only really started happening since I installed the Crane CDI ignition unit. I also installed new plugs, but with a greater plug gap than what I was running without the Crane CDI.
I use to run stock 0.024"/0.6mm gaps, but now run at 0.040"/1.0mm.
Any idea? Could it possible be unburnt fuel igniting in the headers? In which case, should I decrease my plug gaps a bit?
'89 911 Turbo Cab
Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition