Vehicle is a 1974 International Scout II
345 V8
4 speed manual
edelbrock 1406 carburetor
When the engine is cold, everything runs fine. However, once it warms up, it will surge and buck under load, but intermittently. The issue most commonly occurs on hills, but occasionally it happens when at a steady cruise on flat terrain. When it happens, it feels like half my cylinders quit firing. If I pull over when it happens, it will idle very rough for 30 seconds or so, then return to normal. The issue will recur after driving a short distance again. If I stop and turn off the engine for 5 minutes or so before starting out again, it gets much further down the road before happening again.
The ignition is a new Davis Unified Ignition from performance distributors, plugs and wires are new, as is the electric fuel pump and filter. The Edelbrock 1406 is also new, and was installed and tuned by a local shop. I don't think it's a fuel problem, as my pressure is pretty stable at 5.5 psi. I don't have an in-dash fuel pressure gauge, but I've noticed the pressure at the normal 5.5 reading before the idle returns to normal when the issue occurs.
Another point, which may or may not be relevant, is the alternator. I'm currently running an alternator of unknown origin that had been sitting around for who knows how long. It was tossed in as an emergency replacement, but I had not driven the vehicle prior to installing this alternator. The vehicle sat for the prior 18 months.
345 V8
4 speed manual
edelbrock 1406 carburetor
When the engine is cold, everything runs fine. However, once it warms up, it will surge and buck under load, but intermittently. The issue most commonly occurs on hills, but occasionally it happens when at a steady cruise on flat terrain. When it happens, it feels like half my cylinders quit firing. If I pull over when it happens, it will idle very rough for 30 seconds or so, then return to normal. The issue will recur after driving a short distance again. If I stop and turn off the engine for 5 minutes or so before starting out again, it gets much further down the road before happening again.
The ignition is a new Davis Unified Ignition from performance distributors, plugs and wires are new, as is the electric fuel pump and filter. The Edelbrock 1406 is also new, and was installed and tuned by a local shop. I don't think it's a fuel problem, as my pressure is pretty stable at 5.5 psi. I don't have an in-dash fuel pressure gauge, but I've noticed the pressure at the normal 5.5 reading before the idle returns to normal when the issue occurs.
Another point, which may or may not be relevant, is the alternator. I'm currently running an alternator of unknown origin that had been sitting around for who knows how long. It was tossed in as an emergency replacement, but I had not driven the vehicle prior to installing this alternator. The vehicle sat for the prior 18 months.
May 13, 2008 at 11:31 AM