QuercusRubra
Registered User
99.5 F550 7.3 Powerstroke 4x4 ZF6
Makes a knock when driving that has a metallic ring to it. Sometimes it's barely there in the diesel noise, occasionally it's so loud that nobody can miss it.
Computer is reporting cylinder contribution failure on #4 and #8. However, I swapped them with #2 and #6 and the cct failure stayed on #4/8. All 8 are new rebuilt from Full Force diesel. New glow plugs, new vc gasket, new icp sensor, ipr valve, cps sensor among others. Completely resealed fuel and hp oil systems with hutch mod, regulated return, hp oil x-over, no fuel or oil leaks up top, except for drin valve just started and possibly the ebp valve leaking a bit of oil when active, but the valley is clean.
I just did a compression test pretty much cold and dry, tho a little oil was likely in the cylinders from the glow plug holes. I vacuum out the oil from on top of the glow plug before I remove it, but there's probably a little anyway? Found all cylinders between 380 and 425, but #8 is one of the highest the middle ones are a bit lower, but I don't think that's a lot, is it?
HPOP at idle is a little under 600psi at startup and a little over 500 hot., maxing out around 2800 with 35% duty cycle, (to the best of my memory). Fuel pressure is solid 62 to 64 always.
Pulling the electrical plug to each cylinder whe its running makes it stumble pretty badly on each cylinder. About the same to my ear.
So what's causing this knock, puffs of smoke at the tailpipe, shaking engine/cab like it's missing and cct failure, but compression is pretty good and compression is really good on one of the failing cylinders, and the failure didn't follow the I jector to a new cylinder?
I'd say it starts well and has pretty decent power. I can tow a 13k trailer 30 to 40mph up a moderate hill from a stop, and I'm weighing a little over 23k total
When I got it, the fuel pickup was pretty bad, and my theory was it sucked a lot of air and killed the injectors? There were times when it ran OK, and times when it was a challenge to make it over a bridge on a flat highway goi 30 to 40 mph, and it would pour out smoke. And it leaked buckets of oil and fuel, I think. When I got it back it could start/run/drive OK, but when I Rev it up or under hard load it cackled walnuts going through a grinder and made a huge cloud of smoke.
What kind of internal damage could this situation cause? Could it make a rod knock? Given that you can't run a powerstroke low on oil I don't really know what makes a rod knock?
See my other videos in this: compression tests on each cylinder, cold starts.
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Makes a knock when driving that has a metallic ring to it. Sometimes it's barely there in the diesel noise, occasionally it's so loud that nobody can miss it.
Computer is reporting cylinder contribution failure on #4 and #8. However, I swapped them with #2 and #6 and the cct failure stayed on #4/8. All 8 are new rebuilt from Full Force diesel. New glow plugs, new vc gasket, new icp sensor, ipr valve, cps sensor among others. Completely resealed fuel and hp oil systems with hutch mod, regulated return, hp oil x-over, no fuel or oil leaks up top, except for drin valve just started and possibly the ebp valve leaking a bit of oil when active, but the valley is clean.
I just did a compression test pretty much cold and dry, tho a little oil was likely in the cylinders from the glow plug holes. I vacuum out the oil from on top of the glow plug before I remove it, but there's probably a little anyway? Found all cylinders between 380 and 425, but #8 is one of the highest the middle ones are a bit lower, but I don't think that's a lot, is it?
HPOP at idle is a little under 600psi at startup and a little over 500 hot., maxing out around 2800 with 35% duty cycle, (to the best of my memory). Fuel pressure is solid 62 to 64 always.
Pulling the electrical plug to each cylinder whe its running makes it stumble pretty badly on each cylinder. About the same to my ear.
So what's causing this knock, puffs of smoke at the tailpipe, shaking engine/cab like it's missing and cct failure, but compression is pretty good and compression is really good on one of the failing cylinders, and the failure didn't follow the I jector to a new cylinder?
I'd say it starts well and has pretty decent power. I can tow a 13k trailer 30 to 40mph up a moderate hill from a stop, and I'm weighing a little over 23k total
When I got it, the fuel pickup was pretty bad, and my theory was it sucked a lot of air and killed the injectors? There were times when it ran OK, and times when it was a challenge to make it over a bridge on a flat highway goi 30 to 40 mph, and it would pour out smoke. And it leaked buckets of oil and fuel, I think. When I got it back it could start/run/drive OK, but when I Rev it up or under hard load it cackled walnuts going through a grinder and made a huge cloud of smoke.
What kind of internal damage could this situation cause? Could it make a rod knock? Given that you can't run a powerstroke low on oil I don't really know what makes a rod knock?
See my other videos in this: compression tests on each cylinder, cold starts.
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