Customanalog
07-01-2006, 22:28
Hi all, I let my membership lapse, but just renewed. I'm puzzled by this one: 85 Suburban 6.2 with 145K on chassis. Bought in 2004 with 124K miles, from California, and the dealer said the engine was replaced at 100K miles in 2001. Truck had been used for towing before the replacement. Valve covers say GM Goodwrench 6.5, but the injectors are for a 6.2. No turbo.
All was well for 5K miles, then noticed a heavy knock on the right one day while accelerating. Went away for a few weeks, then came back occasionally. Within the last year, loud knocking from the right side occurs every time 1) the engine is warming up for the first time that day, say at 150 degrees. If I let off on the pedal for 30 seconds, it goes away and stays away for the rest of the day unless 2) I floor it going up a long hill or 3) come to a long slow stop at a light and then accelerate moderately. There is generally not a problem driving at normal highway speeds. Loading the engine does it.
The knocking is accompanied by a MASSIVE CLOUD of grey smoke from the right bank, which smells like burning crankcase oil. Problem is worse in Winter, less in Summer, but it can burn a quart of Rotella in 70 miles if I have to climb hills. The engine does not smoke in flat terrain driving, or for more than a few seconds after startup.
So I replaced the injectors. The one nearest passenger compartment (#8?) was pretty fouled. Problem remained. Checked #8 again after 100 miles of driving. Pretty fouled again. My mechanic checked compression, which is between 300 and 320 all cylinders. Then he pulled the injector lines, cranked the engine and noticed that more fuel comes out of #8. Boston Fuel Injection, which rebuilds GM pumps, says that's impossible with a rotary pump, and to try advancing the pump just a bit to compensate for wear. That was done also, with no change.
I've talked to a number of guys with extensive diesel experience. Consensus seems to be to "get a new pump and if that doesn't fix it, a short block." Any ideas appreciated... Thanks!
All was well for 5K miles, then noticed a heavy knock on the right one day while accelerating. Went away for a few weeks, then came back occasionally. Within the last year, loud knocking from the right side occurs every time 1) the engine is warming up for the first time that day, say at 150 degrees. If I let off on the pedal for 30 seconds, it goes away and stays away for the rest of the day unless 2) I floor it going up a long hill or 3) come to a long slow stop at a light and then accelerate moderately. There is generally not a problem driving at normal highway speeds. Loading the engine does it.
The knocking is accompanied by a MASSIVE CLOUD of grey smoke from the right bank, which smells like burning crankcase oil. Problem is worse in Winter, less in Summer, but it can burn a quart of Rotella in 70 miles if I have to climb hills. The engine does not smoke in flat terrain driving, or for more than a few seconds after startup.
So I replaced the injectors. The one nearest passenger compartment (#8?) was pretty fouled. Problem remained. Checked #8 again after 100 miles of driving. Pretty fouled again. My mechanic checked compression, which is between 300 and 320 all cylinders. Then he pulled the injector lines, cranked the engine and noticed that more fuel comes out of #8. Boston Fuel Injection, which rebuilds GM pumps, says that's impossible with a rotary pump, and to try advancing the pump just a bit to compensate for wear. That was done also, with no change.
I've talked to a number of guys with extensive diesel experience. Consensus seems to be to "get a new pump and if that doesn't fix it, a short block." Any ideas appreciated... Thanks!