bluesh smoke when off accelerator
Thread Starter
|
Senior User
Joined: Nov 2005
Posts: 138
Likes: 0
From: ky
bluesh smoke when off accelerator
i just put a used 7.3 inmy 92 rollback. i had a problem with it dying after starting(leaking connector at the tank selector), sputtering and blue smoke @2200 rpm(couple of fuel filter changes to clean out the old diesel). it has ran fine for about 2 weeks. now i've noticed when i'm running about 55mph and up and in the range of 2400 rpm and up, when i let off the accelerator the truck will puff out some bluesh/white smoke. if i'm going down hill and ease off it will smoke nonstop until the rpms get below 2400.this truck is geared really low in the rear and has a zf 5spd, it can run about 55-60 mph @ 2400 to 2800 rpm, loaded or unloaded. also i noticed yesterday when i was loaded pretty good, occasionally i would get a slight bit of black smoke when climbing some grades, not too bad though. the motor i put in had about 120k on it but ran great and leaks no oil.i have not done an oil change yet, after new stuff at the swap 500 mi ago.i did notice my oil pressure runnung at the "o" in "normal" yesterday after having been at the "r-m" before, if that means anything.any ideas, tips or warnings on this stuff is greatly appreciated.
Tuned
Joined: Nov 2002
Posts: 348
Likes: 0
From: Benson, AZ
When you put the used motor in did you change the oil pressure sensor? also check the timing on the motor. that is where i would start. also what color is the smoke the rest of the time?
just my thought
scott
just my thought
scott
Posting Guru
Joined: Aug 2006
Posts: 2,175
Likes: 0
From: Kent WA
I would suspect one of two things are causing your smoke
1) timing is too slow - this is the easier of the two to fix just advance the timing a little at a time until you start to hear the "powerstroke rattle" (pinging)
2) valve seals are shot & sucking oil past them into the cylinders when you let off the throttle. If this is the problem its a tougher to fix, but it can be done without removing the heads. There is a tool that you can use to compress the springs and remove them from the valves without removing the heads. You have to do one cylinder at a time - get that cylinder to TDC & blow high pressure compressed air into the cylinder through the glow plug hole to keep the valves from dropping while you replace the stem seals.
Thats my 2 cents - as always YMMV......
1) timing is too slow - this is the easier of the two to fix just advance the timing a little at a time until you start to hear the "powerstroke rattle" (pinging)
2) valve seals are shot & sucking oil past them into the cylinders when you let off the throttle. If this is the problem its a tougher to fix, but it can be done without removing the heads. There is a tool that you can use to compress the springs and remove them from the valves without removing the heads. You have to do one cylinder at a time - get that cylinder to TDC & blow high pressure compressed air into the cylinder through the glow plug hole to keep the valves from dropping while you replace the stem seals.
Thats my 2 cents - as always YMMV......
Posting Guru
Joined: Oct 2003
Posts: 2,438
Likes: 0
From: Monroe, WA
I'd agree with a timing issue causing the smoke. Maybe the advance piston sticking in the pump? Run lots of lubricity additive in your fuel, there isn't any in the fuel anymore. Pretty hard for valve seals to suck enough oil to see smoke while driving.
Elder User
Joined: Apr 2006
Posts: 894
Likes: 0
From: South Dakota
Originally Posted by CheaperJeeper
2) valve seals are shot & sucking oil past them into the cylinders when you let off the throttle. If this is the problem its a tougher to fix, but it can be done without removing the heads. There is a tool that you can use to compress the springs and remove them from the valves without removing the heads. You have to do one cylinder at a time - get that cylinder to TDC & blow high pressure compressed air into the cylinder through the glow plug hole to keep the valves from dropping while you replace the stem seals.
Thread Starter
|
Senior User
Joined: Nov 2005
Posts: 138
Likes: 0
From: ky
thanks for the tips.how exactly do i advance the timing.the lines on the ip and case are lined up.no i didn't change the oil pressure sensor.i didn't change the injectors.new return lines.new lift pump.it doesn't smoke any other time besides just a little at start up. could it be caused by another leak in the fuel lines, that could be causing it and at start up? i don't think it's worth tackling the valve seals.thanks again.
Thread
Thread Starter
Forum
Replies
Last Post
harley4jcs
Excursion - King of SUVs
18
Nov 24, 2015 10:24 AM
