Exhaust Smoke - blue

[pfeffer1728]

Well, After an almost 8 month hiatus from the forum...I'm back to the Bronco.

I got my 4bbl and intake installed, and it runs about 10x better than it did before. HOWEVER, there is a considerable increase in blue smoke out the driver's side exhaust. obviously, burning oil. not really at idle but under throttle, yes. After searching and reading a few threads here it seems like I need to do the following:

check plugs (rear one on driver's side was coated pretty bad, but could have been due to rich fuel mixture and choke not working properly...both of which are fixed now)

compression test
report back to you guys to see if I need to attack:
valves
or rings


thoughts?

[96EB5.8]

Check the pcv system for stuck open or oil coming through.

[TheUnforgiven]

i agree with 96EB, check to make sure the PCV system is intact and functioning properly.

however, smoke under power typically indicates the rings are shot. do a comp test dry. record the numbers. then squirt some oil into the cylinders. recheck compression "wet" test. if the compression numbers increase during the wet test, you have a ring issue.

[pfeffer1728]

10-4. I've checked PCV before but only to make sure it had good suction...what's the procedure for testing the system?

[prchrman]

do not know about your year model but older model fords had modulator on auto tranny that went bad and it leaked into right bank somehow, intake i think but was on right side.

[pfeffer1728]

Originally Posted by prchrman

do not know about your year model but older model fords had modulator on auto tranny that went bad and it leaked into right bank somehow, intake i think but was on right side.

?

[TheUnforgiven]

he's referring to the vacuum modulator on the back of the automatic transmission. it controls how and when the transmission shifts. it is operated by engine vacuum, and when the diaphragm fails it can cause the engine to suck up ATF and burn that. easy to check.

[pfeffer1728]

good to know. would that affect how it shifts, and would i be able to feel it? (won't be able to actually look at it til i get home)

transmission feels pretty good. other than holding 2nd a little longer than i feel like it should, it feels good and strong.

[TheUnforgiven]

Depends on how back the leak is. maybe, maybe not. all you gotta do is pull the vacuum line off the modulator. if it has ANY hint of atf in it, the modulator is bad.

Is that your source of blue smoke? i don't know, but it's a 5 minute thing to check.

[96EB5.8]

To ck the pcv just install a new one if there is any question. look in the hose for much liquid oil and make sure the hose is not clogged.
X3 on the trans modulator ck easy to do

[CBboots]

Originally Posted by prchrman

do not know about your year model but older model fords had modulator on auto tranny that went bad and it leaked into right bank somehow, intake i think but was on right side.

Originally Posted by TheUnforgiven

he's referring to the vacuum modulator on the back of the automatic transmission. it controls how and when the transmission shifts. it is operated by engine vacuum, and when the diaphragm fails it can cause the engine to suck up ATF and burn that. easy to check.

That tibit is worth it's weight in gold.
I hadn't seen/heard about that in years...you guys each get a cookie.

[pfeffer1728]

I'll have to check this either this afternoon or this weekend...i get to work before the sun comes up and leave after it sets. doesn't leave a lot of room for bronco-ing.

especially since i have no garage. (maybe in my next house????)

[pfeffer1728]

well it's not the modulator. pulled the vac hose and it was clean inside.

on to compression testing... whenever i get time.

[johnnyreb]

You might want to check the little filter in the air breather--where the hose comes from your pcv. If it is stopped up--it will cause smoke. The vapors has no where to go but build up in your valve cover and seeps into the valves and plugs. It caused mine too.