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exhaust sucking in air

8K views 13 replies 6 participants last post by  T.Neff 
#1 ·
hey me with the 88 v6 tbi... what does it mean when air is being sucked in through tailpipe? the idle is also bad. i held a dollar bill up to the tailpipe and it got sucked in and out, sucked in then out, etc. its not rhythmic, its sporadic, its worse when warm. thanks for the help....
 
#3 ·
actually a friend on here, paintdrying, has already answered this. it was due to worn valve spring and the valves not seating properly. I was just wondering if anyone could elaborate more on this so i can understand how and why this happens. and if there are other possible reasons why air gets sucked in through exhaust and the popping sounds please let me know
 
#6 ·
Mine didn't break. Soak with plenty of PB, often, for a day or so. Tap every once in a while; that seems to help the capillary action.

If you break a stud, you drive or drill it out and put in a new one.

If it's the manifold, yep, you'll need to replace the manifold gasket.
 
#7 ·
Look at your donut gasket, Use lots of pb blaster, days before you plan to do the work start spraying the bolts / studs, 2-3 times each day until you do the job. Work the nut off the stud like you were tapping a new hole, a little forward a little back, don't just crank them off. If you break one or more you will be tapping holes. The manifold is not likely cracked, a bad gasket maybe but I would bet dollars to dough nuts on the donut :lol:
 
#10 ·
Does this van have flat tappet lifters?

The popping and sucking into exhaust you are describing can be a symptom of a collapsed lifter and/or a round cam exhaust lobe. Is there any lifter tick? This can still happen to hydraulic roller lifters.
 
#11 ·
A rounded cam lobe would mean that lobe isn't providing lift and therefor isn't opening the valve.Because of that,it couldn't be sucking air.A burnt valve on the other hand staying open would or one the possibly has bad guides/seals would suck air.Thing is the valve has to be staying open for whatever reason.
 
#13 ·
i believe i have hydraulic lifters. When engine is cold it does kinda have a tapping sound. it happens when in drive and at a very low speed, 1-15 mph, and when engine warms up it goes away. The van still really does drive good, theres just alot of smoking and loss of power after 45 mph, i just have to push in on accelerator alot trying to keep at 60 mph or more and especially going up hills. I got a code 43 at wot a few times so i look down at knock sensor and wire was all chewed up, i just spliced a wire in between, hopefully it'll work. everything down there is oil soaked. I have been to weary about going to wot, just dont like to kill engine any faster lol. uncle says going to wot wont hurt it.
 
#14 ·
Sure does sound like bad valve guides/seals solely because of it smoking .It doesn't exclude the possibility of a lifter miss-adjusted or lifters that are bad as well or a valve is burnt on the exhaust side of it.I suggest it is time to take it apart and start looking for these problems.Once it is apart,take those heads into a machine shop to have them checked out/pressure tested and repaired.
 
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