Motor Going?? PLEASE HELP
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
It will cause the motor to run excessively lean which leads to detonation.. that's the stumbling and vibration you feel under load, and if this goes on long enough it can result in piston damage and lower compression. I had a 5.0 that developed a serious misfire and stumble that would show up as soon as the engine warmed up if you were highway driving, around town it wasn't as noticable. It never threw a code and eventually I figured out the tube at the back of the motor had rotted out. Once the tube was replaced the stumbling and misfire completely disappeared, but the damage was already done, the engine had suffered permanent and significant power loss.
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Yes, that's part of the thermactor system. The little can on top is the air dump from the TAB valve down behind the air pump, and the bigger can is the air intake filter for the air pump. If you're not getting air out the dump at idle then the TAB valve is stuck open which directs the air from the pump into the heads or cats, depending upon the position of the TAD valve behind the motor. This extra air would cause the O2 sensor to read lean and the computer would add more fuel to compensate, so milage will suffer. You need to completely fix or completely remove this system or you'll continue to have problems.
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
Yes, that's part of the thermactor system. The little can on top is the air dump from the TAB valve down behind the air pump, and the bigger can is the air intake filter for the air pump. If you're not getting air out the dump at idle then the TAB valve is stuck open which directs the air from the pump into the heads or cats, depending upon the position of the TAD valve behind the motor. This extra air would cause the O2 sensor to read lean and the computer would add more fuel to compensate, so milage will suffer. You need to completely fix or completely remove this system or you'll continue to have problems.
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
You really don't want any fresh air getting into the exhaust upstream of the O2 sensor, so it's not a good idea to just disconnect it and let it hang. Once you remove the tube at the back of the motor and plug the heads, and disconnect the line to the air pump the whole system will be hanging loose so it'll be pretty easy to see what needs to be removed. The only other thing that may cause issues are the vacuum lines that feed the TAB and TAD valves, just plug these and tie them up out of the way.
Thread Starter
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
You really don't want any fresh air getting into the exhaust upstream of the O2 sensor, so it's not a good idea to just disconnect it and let it hang. Once you remove the tube at the back of the motor and plug the heads, and disconnect the line to the air pump the whole system will be hanging loose so it'll be pretty easy to see what needs to be removed. The only other thing that may cause issues are the vacuum lines that feed the TAB and TAD valves, just plug these and tie them up out of the way.
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
Update
Finally got around to doing this right.
This is the tubing that connects both heads correct?
This is the end where the check valve rusted out at? Where was the other end connected to?
Here's a pic of the hose that im pretty sure rusted off of this piece.
This is the tubing that connects both heads correct?
This is the end where the check valve rusted out at? Where was the other end connected to?Here's a pic of the hose that im pretty sure rusted off of this piece.
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
Also, how tight should these bolts be. I got them in now and they aren't super tight, but didnt want to mess up any threads due to over tightening. I used two oil pan plugs with the rubber seal under the head. Not sure if the seal will stay due to heat, but its all i could find for the time being that would thread in there while the motors still in the truck. I may just weld a plate over these holes when i pull it.
Elder User
Joined: Nov 2008
Posts: 639
Likes: 0
From: houston
I `ve seen where people just flipped the ends of the fittings on the cross over tube to make them sit flush on th head but it would be better to find some plugs from auto parts store
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
Thanks. Im going to see if advanced or autozone have these because Home Depot or Lowe's didnt have any 5/8 bolts this small in length
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
You CAN use longer bolts but I'm not sure how long the threads reach. Did you try a DO IT BEST center, or an ACE hardware or even TSC? I have a local mom and pop DIB center that has almost everything you could imagine, decent prices too.
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Cargo Master
Joined: Oct 2008
Posts: 2,308
Likes: 1
From: Elyria, OH
We used to have a Do It Yourself place that had everything you can imadgine, but it got closed. sure do miss that place. Ill be going to look around tonight after work. TSC and a few auto parts stores.
Post Fiend
Joined: Nov 2008
Posts: 23,849
Likes: 20
From: McKenzie River
5/8-11 bolts may not be available in 3/4 length, 1 in may be the shortest you can get. You may have to take longer bolts to a machine shop and have them cut down, and your gonna have to find a bolt with full threads, one with a shoulder wont have enough threads if you get it cut down.
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