Alright gang, it's time for a different sort of problem. I finally joined the SBC club a few weeks ago, and so far it sucks. I have a 1996 LT1in a Buick B-body that intermittently bogs down. Much of the time it runs perfectly, and then it will appear to drop out 2 or even 3 cylinders. This has happened in a variety of situations. Hot, cold idle, cold starting, WOT, warm idle, while aimlessly cruising down the road, etc. When this situation develops, the engine runs rough at low engine speeds, and kinda smooths out at higher engine speeds. Cold starts are sometimes hard, and require throttle input, but are still happening (so far). And other times it fires right off immediately. It doesn't hit a firm power ceiling (like with a plugged fuel filter). And both exhaust banks smell very rich. So I don't think it's running out of fuel. Fuel regulator issues would cause funny running, but the abrupt coming and going of this problem, combined with the mix of well-running and non-running cylinders makes me think I'm dealing with a spark issue. No DTCs are present, though it did briefly have P0125 (Insufficient Coolant Temperature For Closed Loop Fuel Control). This has not recurred yet, and shouldn't affect open-loop operation. It also had P0410 (Secondary Air Injection System Malfunction), but that was in place before the engine got tempestuous.
This engine is famous for having distributor issues. The distributor mounts at the front of the camshaft, low to the ground and behind the water pump. A crummy spot for a water-sensitive item.
It's the rainy season, so the underbody is getting wet routinely. I never figured I'd own another vehicle with a distributor, especially in a non-project DD car. I love them almost as little as I love carburetors.
The car has 130,000 miles, and I don't know how old plugs/wires/cap/rotor are. So I should look at easy stuff first (even though I don't think a trashed plug should suddenly change its behavior every few minutes). I haven't been stranded yet, but I'm only a few days into this problem. Looking at the long-term picture, a replacement AC Delco Optispark unit will probably outlast the car. But it's still not water-resistant. This is a 1996 model, so it already has GM's upgraded air venting system installed. It also should already have a crankshaft position sensor according to the interwebz (haven't checked yet).
A few years ago there were coil-on-plug conversion kits for LT1 engines on the market. Today it seems to be no longer loved and supported by the market (insert dumb diesel joke here
). I've found a few expensive aftermarket ignition timing boxes that will either decode the optispark output or use an added crank position sensor to feed an LS1 PCM.
But the more I think about it, the more I wonder why an expensive box is required. Isn't this a problem that dozens of other GM engines have already solved? If I already have a crank position sensor, isn't that the same signal that an LS1 PCM is expecting to decode? Is a camshaft position sensor needed? I know my S-series cars run fine without such. It seems like my worst-case scenario should be buying a different style of CPS, not buying an $800 signal decoder.
Or am I crazy?
This engine is famous for having distributor issues. The distributor mounts at the front of the camshaft, low to the ground and behind the water pump. A crummy spot for a water-sensitive item.
It's the rainy season, so the underbody is getting wet routinely. I never figured I'd own another vehicle with a distributor, especially in a non-project DD car. I love them almost as little as I love carburetors. The car has 130,000 miles, and I don't know how old plugs/wires/cap/rotor are. So I should look at easy stuff first (even though I don't think a trashed plug should suddenly change its behavior every few minutes). I haven't been stranded yet, but I'm only a few days into this problem. Looking at the long-term picture, a replacement AC Delco Optispark unit will probably outlast the car. But it's still not water-resistant. This is a 1996 model, so it already has GM's upgraded air venting system installed. It also should already have a crankshaft position sensor according to the interwebz (haven't checked yet).
A few years ago there were coil-on-plug conversion kits for LT1 engines on the market. Today it seems to be no longer loved and supported by the market (insert dumb diesel joke here
). I've found a few expensive aftermarket ignition timing boxes that will either decode the optispark output or use an added crank position sensor to feed an LS1 PCM.But the more I think about it, the more I wonder why an expensive box is required. Isn't this a problem that dozens of other GM engines have already solved? If I already have a crank position sensor, isn't that the same signal that an LS1 PCM is expecting to decode? Is a camshaft position sensor needed? I know my S-series cars run fine without such. It seems like my worst-case scenario should be buying a different style of CPS, not buying an $800 signal decoder.
Or am I crazy?
