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How to test compression in a diesel?

Posted: Thu Jul 19, 2007 9:26 pm
by 4WD WOG
hey guys,

just wondering weather you test compression when the engine is warm or cold? and what should compression read? motor is SD33T, 315000kms

cause im gettin a bit worried, the old mk SD33T blows a fair bit of white smoke, have only recently bought it as well :(

think glow plugs are almost gone cause takes a while to start and when it does start i need the manual choke to hold the revs up otherwise it will stall, when it gets warm its not to bad, no smoke when idling but when u give it a rev white smoke...

Posted: Fri Jul 20, 2007 6:58 am
by mickyd555
Does it blow white smoke only when cold or all the time?

sounds like fuel delivery rather than compression. Go see Craig at Highway Diesel

www.highwaydiesel.com.au

Posted: Fri Jul 20, 2007 6:04 pm
by 4WD WOG
mickyd555 wrote:Does it blow white smoke only when cold or all the time?

sounds like fuel delivery rather than compression. Go see Craig at Highway Diesel

www.highwaydiesel.com.au
havent really driven it but the guy i bought it off named "broke" on this forum said he drove it every day to work and back and only smoked when cold, but i started her up yesterday after a few days of sitting and blew an embarrasing amount of white smoke until it warmed up, but still once it was running for about 20 mins and i put the excellerator down just whilst sitting there it blew a nice clowd of white smoke

Posted: Sat Jul 21, 2007 6:06 pm
by Wish I had coils
My mk blows a heap of white smoke on start up, :cry: i barely let it warm up maybe 2-3 minutes back out the drive way. after driving it a don't get any white smoke. But if i just let it idle in the drive and give it a rev it blows white smoke. like you described, so my suggestion is don't worry to much about it just drive it, it should go away if not then start to worry a bit :D
Hope this helps your stressing

Posted: Mon Jul 23, 2007 10:59 am
by lay80n
With diesels, white smoke is incomplete combustion. If its on cold startup then glow plugs/poor compression are often the cause.

Layto....