So i'm having a bad time starting my 1985 3b motor. It takes about 30 to 40 seconds of cranking and when it eventually starts there's a loud knocking noise from the motor but immediately stops. The idle speed and acceleration vibration is immense and does not ease even at temp. Also there's a pretty noticeable burning smell from the fumes upon start up. Any help would be much appreciated
3b Motor struggling to start / Knocking noise and rough idle (1 Viewer)
- Thread starter Rosco
- Start date
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Glow plugs working? Blowing smoke?
- Thread starter
- #3
Yeah well it seems like they are. It takes a few seconds before smoke comes out of the exhaust although it's very smelly. Like a lot more so than diesel burning.
stevebradford
In the shop
Sounds like one cylinder is toast or at least not firing. First I would do a compression test you need a diesel compression gauge that will go up to at least 500psi. And you will likely find one cylinder low.
Similar story (no knocking) i had a rough running 3b with decent compression ran super rough at anything over an idle took the head off and found two valve springs broken but still holding the valve closed. Not likely your issue, start with the compression test.
Similar story (no knocking) i had a rough running 3b with decent compression ran super rough at anything over an idle took the head off and found two valve springs broken but still holding the valve closed. Not likely your issue, start with the compression test.
Most likely a glow plug or compression problem, or both.
- Thread starter
- #6
Ok thanks for that I'll see how I go removing the head and hopefully I get an answer.
Have you had it long and how many klms has it done? I would compression test it and test the glow plugs before doing anything expensive.
What colour smoke is it making? Does it start white/grey and seem to be pumping from 1 or 2 cyls in time with their compression stroke?
What colour smoke is it making? Does it start white/grey and seem to be pumping from 1 or 2 cyls in time with their compression stroke?
