This one is making me crazy. Here are the symptoms: Customer reported an overspeed situation It Does Run Lots of smoke, rough running. Made the shop toxic in less than a minute. Cylinder 3 is about 50 degrees colder than the others Compressions are between 375 and 400 Injection pump timing is correct, as far as I can tell (not 100% on this one yet). What I done did: new injectors new fuel filter checked compressions cold and warm oil level ok coolant ok overhead in process (valve cover studs are rusted, soaking them at the moment) I ran a little experiment on the injection pump. Never tried this before. I connected rubber hoses to the hard lines, and ran them to 10cc syringes, so I could watch the volume as closely as my hucklebuck talents would allow. This test showed #3 and 4 to be very consistent, not a measurable difference. #1 is consistently a little low and #2 is consistently a little high. By "little" I mean between 1 and 2ccs of fuel with 60 seconds of cranking. In other words, I'd empty the syringes, crank the engine for 60 seconds (injectors removed and battery on charger), and #3 and #4 would be about 8cc. #1 would be about 7cc and #2 would be about 9cc. I ran this experiment several times and got the same result each time. I even swapped around hoses and syringes to make sure they weren't to blame. This is as close as I can get to bench testing an injection pump. It's a Stanadyne db2, which is a rotary pump. If one output is low, you expect the opposing cylinder output to be low also, just because how the rotary style pump works. That's not what's happening, 1 and 2 are directly adjacent to each other on the pump, they're not 180 from each other. So, I got nothing there. I don't have the manual for this engine. I posted in the SMTP, maybe somone can help there. I can't be 100% sure of the injection pump timing, but I took the cover off from the front of the injection pump, and with #1 TDC (as close as I can get it) on compression, the mark on the gear points to the crankshaft. If it skipped a tooth, I'd see it. All teeth seem to be intact. Any and all thoughts appreciated!
Remove the injection pump drive gear retaining nut. I believe with the injection pump is at TDC # 1 the key and keyway is at 12 o’clock.
Thanks! Do I have to worry about dropping that gear?
At this point your just removing the nut and washer to get a visual of the key and keyway, not pulling the gear or removing the injection pump.
How about posting a picture of the injection pump? Did you perform a cylinder leak down test? Definitely check those valve adjustments.
The pump is a stanadyne db2. I normally don’t do leakdowns when compressions are as good as this, but it certainly couldn’t hurt. I let those studs soak overnight. I’m hoping they don’t break when I take em off today.
Someone didn't put DEF in the fuel tank did they?
I don’t think he’s dumb enough to do that, but boy that’s a good question. I’ll run an aux tank today and see if that improves anything.
Keyway is not straight up, it's pointed toward the water pump.
Overheads are fine. I'm on to running an aux fuel setup.
Coming up empty handed. I've done everything I can think of, and cyl 3 is still cold, and it's still smoking like crazy. There are a few more air bubbles in that system than I would expect, but I don't think that's my primary issue. I think that injection pump needs to come out. I made a crappy video for you to laugh at
The above mentioned keyway is not sheared? Rest of fuel system clean? Confident in new injectors?
I’m going to pull the pump tomorrow and take it in. If the key is sheared that could be the culprit. Injectors are new, and I checked em anyway, all cracking at 3400. System is clean, and as of this running, fuel is fresh.
Actually, I did check the key way today. I forgot . Not sheared.
I didn't take the injection pump in last week because my daughter got sick and had to take a little holiday form school (strep, shes fine now). Anyhow, I came in this morning to to just try the aux fuel setup one more time, just to be sure. No change. I did notice that there were 2 timing marks on the injection pump, and you can see by the paint, that the pump had been moved since it came from the factory. Just on a whim, I put it back to covering the paint and lining up with that other mark, and it runs much better. Still smokes a bit on startup, and still a little rough, but it looks like this was a timing issue all along. I'm having a hard time believing it, but there we are. I"m going to move the pump just above that lower line just to see if that improves things a little more, and see what happens.