mayvillain
Newbie
Just finished a top-end rebuild on my '92 K1500 and it runs AWFUL. Ran perfect before blowing a head gasket. Here are the symptoms I'm seeing:
1. Rough idle on start with loud 'hissing' noise coming from throttle body (without air cleaner installed).
2. Muffler (mid-truck) sounds like a washing machine; an almost 'banging' or rumbling sound (like shaking a coffee can with a baseball inside).
3. After a few minutes of warming up, the idle smooths out, hissing from throttle body/intake manifold stops, and it actually seems to idle kinda normal.
4. When in neutral, truck revs pretty normal. In any gear, including Park, runs rough with low idle and almost stalls at times.
5. When driving, NO power. After about 15-20MPH, I can floor it with no throttle response. Can barely get up a steep hill at 5PMH.
6. If driving on flat road, there seems to be a delayed throttle response; like it will pick up speed after a few seconds if I keep my foot down.
Some other observations:
- Truck PASSES the coolant combustion test; there is no exhaust gas in the cooling system
- Upon spraying carb cleaner around intake manifold seals while running, NO CHANGE in revs
Here is a list of all the work I did:
- Cylinder heads machined (no cracks) and valves re-seated by reputable machine shop
- Replaced head gaskets (Fel-Pro)
- Replaced intake gaskets (Fel-Pro)
- New water pump + gaskets (Fel-Pro)
- New radiator (OEM-style replacement from O'Reilly)
- New thermostat
- New PCV valve
- New oil pressure sensor (my gauge was always just bouncing around since I've owned the truck ~2 years)
- New TBI gaskets (Fel-Pro)
- New timing chain
- New distributor (rotor + cap)
- New spark plugs (Iridium, no gap) and spark plug wires
- New TV cable (I broke the original during tear down. This new one has been adjusted by a shop, but I think it might need a slight tightening; still getting a long shift on 1 -> 2)
- Transmission fluid fill
- Properly set lifter pre-load to the best of my ability (spent lots of time on this, used the "Engine RUNNING Hydraulic Lifter Adjustment" protocol
- Oil change
Any idea what might be causing the symptoms #1-6 listed above?
1. Rough idle on start with loud 'hissing' noise coming from throttle body (without air cleaner installed).
2. Muffler (mid-truck) sounds like a washing machine; an almost 'banging' or rumbling sound (like shaking a coffee can with a baseball inside).
3. After a few minutes of warming up, the idle smooths out, hissing from throttle body/intake manifold stops, and it actually seems to idle kinda normal.
4. When in neutral, truck revs pretty normal. In any gear, including Park, runs rough with low idle and almost stalls at times.
5. When driving, NO power. After about 15-20MPH, I can floor it with no throttle response. Can barely get up a steep hill at 5PMH.
6. If driving on flat road, there seems to be a delayed throttle response; like it will pick up speed after a few seconds if I keep my foot down.
Some other observations:
- Truck PASSES the coolant combustion test; there is no exhaust gas in the cooling system
- Upon spraying carb cleaner around intake manifold seals while running, NO CHANGE in revs
Here is a list of all the work I did:
- Cylinder heads machined (no cracks) and valves re-seated by reputable machine shop
- Replaced head gaskets (Fel-Pro)
- Replaced intake gaskets (Fel-Pro)
- New water pump + gaskets (Fel-Pro)
- New radiator (OEM-style replacement from O'Reilly)
- New thermostat
- New PCV valve
- New oil pressure sensor (my gauge was always just bouncing around since I've owned the truck ~2 years)
- New TBI gaskets (Fel-Pro)
- New timing chain
- New distributor (rotor + cap)
- New spark plugs (Iridium, no gap) and spark plug wires
- New TV cable (I broke the original during tear down. This new one has been adjusted by a shop, but I think it might need a slight tightening; still getting a long shift on 1 -> 2)
- Transmission fluid fill
- Properly set lifter pre-load to the best of my ability (spent lots of time on this, used the "Engine RUNNING Hydraulic Lifter Adjustment" protocol
- Oil change
Any idea what might be causing the symptoms #1-6 listed above?
Last edited: