[AT] Isuzu smoke problems

[Bruce Fallon]

I bought a 1986 Isuzu cab forward truck with a 14 flatbed dump ( to haul 
tractors ). This is a 3.9L 4 cyl Turbo Diesel 5 speed manual. The PO had 
replaced the turbo with a later unit which is water cooled the original did 
not have water cooling. From what I understand it was a fairly common 
upgrade. The problem I have is smoke light blue to white on startup really 
bad, after warm-up the following conditions under load smoke is not a 
problem under coasting with no load just using the throttle to maintain 
speed I am blowing light blue smoke.  If I am completely off the throttle no 
smoke, as I transition back to power short cloud of light blue then clean. 
I just had the injectors rebuilt the injectors pressure was low and the 
spray patters were bad to poor.   I changed the oil and filters.
I have not had it very long but I did not notice any drop in the oil level. 
It smells like diesel not engine oil burning. I believe this has 162K miles 
and it is probably a California vehicle with the timing set 6 degrees BTDC. 
According to the book Federal timing is 14 degrees BTDC.
I am surprised at not being able to find very much information on this 
engine on the Net.
One thing I am wondering about is the original turbo had a wastegate on the 
turbo unit to dump excess pressure into the exhaust.  There is no wastegate 
in this system now. I do not know how much boost it is running. In looking 
at pictures of other later engines  they look the same as mine plumbing wise 
with no visible wastegate.

Anyone experience this before or know about these engines.

Bruce Fallon
Freeland WA. 98249
bfallon at whidbey.com 



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