International Full Size Jeep Association
Home Forums Reader's Rigs Tech Library Trail Stories FSJ-List
International Full Size Jeep Association  

Go Back   International Full Size Jeep Association > Tire Kickin' > General FSJ Tech

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 01-09-2021, 02:48 PM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
401 smoking issue

Hey guys, my 401 is smoking badly. It smokes a bit at idle and gets worse at higher rpm.
It's not burning oil or coolant. It starts right up, idles well at 950 rpm, runs strong and sounds good.
I readjusted air fuel mixture, made sure choke is opened all the way and double checked timing.
Everything seems fine besides excessive smoke, which is primarily coming from right side of exhaust.

What do you guys suspect the problem is?
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
  #2  
Old 01-09-2021, 04:14 PM
levelhead's Avatar
levelhead levelhead is offline
232 I6
 
Join Date: Nov 04, 2016
Location: sask. canada
Posts: 200
A faulty modulator valve on your transmission can cause your 401 to suck trans fluid through the vacuum line to it into the intake manifold and burn it. Pinch off or plug the vacuum line temporally (your trans won't shift ) and see it that stops it. If so replace your modulator valve.
__________________
1988 GW (2)
1980 Cherokee Laredo
1979 Wagoneer
1976 J10 401
1977 Wagoneer 401
1977 J10 4 speed
1969 J3000 (2)
1955 CJ3B
1964 Wagoneer
Reply With Quote
  #3  
Old 01-09-2021, 04:58 PM
SC/397's Avatar
SC/397 SC/397 is offline
Administrator
 
Join Date: Feb 01, 2010
Location: Michigan
Posts: 959
This might sound strange but check for a valve cover gasket leak first. If a valve cover is leaking and a exhaust manifold is leaking, the exhaust manifold or header will draw oil in to it and of out the tail pipe in smoke.
__________________
The Squeaky Wheel gets replaced in my world
Reply With Quote
  #4  
Old 01-09-2021, 06:51 PM
Cliff's Avatar
Cliff Cliff is offline
350 Buick
 
Join Date: Mar 30, 2002
Location: Upper East Tennessee
Posts: 778
I had a strange problem where my fuel tank vent line (the one that goes to the charcoal canister) had rusted closed, and on warm days the fuel was building pressure in the tank and pressurizing the fuel line to the carb and richening the mixture, and making tons of black smoke under acceleration. Since this is affecting one side more than the other I wouldn't suspect this, but thought I would throw it out there anyway.
__________________
Cliff Danley
1977 Cherokee S

Reply With Quote
  #5  
Old 01-10-2021, 12:41 AM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
Quote:
Originally Posted by levelhead
A faulty modulator valve on your transmission can cause your 401 to suck trans fluid through the vacuum line to it into the intake manifold and burn it. Pinch off or plug the vacuum line temporally (your trans won't shift ) and see it that stops it. If so replace your modulator valve.

Thanks, I'll check that next time I work on the truck.
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
  #6  
Old 01-10-2021, 12:51 AM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
Quote:
Originally Posted by SC/397
This might sound strange but check for a valve cover gasket leak first. If a valve cover is leaking and a exhaust manifold is leaking, the exhaust manifold or header will draw oil in to it and of out the tail pipe in smoke.
Not seeing a valve cover leak. Installed new gaskets a few months ago.
This reminds me that I plugged exhaust manifold emissions ports back in the summer. The driver side went smoothly. On the passenger side, pieces of inner tube came out with stock bolts. Could this be my issue?
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
  #7  
Old 01-10-2021, 12:52 AM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
Quote:
Originally Posted by Cliff
I had a strange problem where my fuel tank vent line (the one that goes to the charcoal canister) had rusted closed, and on warm days the fuel was building pressure in the tank and pressurizing the fuel line to the carb and richening the mixture, and making tons of black smoke under acceleration. Since this is affecting one side more than the other I wouldn't suspect this, but thought I would throw it out there anyway.

Thanks for your reply. I have a fuel pressure regulator set to 5psi.
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
  #8  
Old 01-15-2021, 07:41 PM
jammer1 jammer1 is offline
232 I6
 
Join Date: Jun 13, 2015
Location: cleveland, ohio
Posts: 25
Could it be bad valve seals (letting oil into the cylinder). May be able to see it on the plugs.
Reply With Quote
  #9  
Old 01-16-2021, 10:05 AM
MysticRob MysticRob is offline
327 Rambler
 
Join Date: Nov 26, 2019
Location: Boise, ID
Posts: 590
Quote:
Originally Posted by brentwood
...It's not burning oil or coolant...Everything seems fine besides excessive smoke, which is primarily coming from right side of exhaust.

I don't see where you've described what the smoke smells like.

You said it's not burning oil or coolant, but how did you verify that?

You also stated it's coming from the "right side of exhaust". Do you mean it's emanating from inside the engine bay or the right side exhaust pipe (assuming you have dual exhaust)?

Hard to help troubleshoot when we're not right there with you, but first I'd ensure you've properly identified the type of smoke (maybe you have, it's just not clear in your posts thus far), then work on identifying where exactly the issue is coming from.
__________________
--Rob--
1988 Jeep Grand Wagoneer / Baltic Blue & Tan
2008 BMW 535xi Wagon / Deep Sea Blue & Tan

My build thread:
https://ifsja.org/forums/vb/showthread.php?t=189245
My Howell TBI Install How-To:
https://ifsja.org/forums/vb/showthread.php?t=189877
Reply With Quote
  #10  
Old 01-17-2021, 11:59 PM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
Quote:
Originally Posted by jammer1
Could it be bad valve seals (letting oil into the cylinder). May be able to see it on the plugs.

I'll check, thanks
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
  #11  
Old 01-18-2021, 12:14 AM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
Quote:
Originally Posted by MysticRob
I don't see where you've described what the smoke smells like.

You said it's not burning oil or coolant, but how did you verify that?

You also stated it's coming from the "right side of exhaust". Do you mean it's emanating from inside the engine bay or the right side exhaust pipe (assuming you have dual exhaust)?

Hard to help troubleshoot when we're not right there with you, but first I'd ensure you've properly identified the type of smoke (maybe you have, it's just not clear in your posts thus far), then work on identifying where exactly the issue is coming from.

My oil and coolant levels aren't noticeably dropping. Smoke doesn't smell like coolant.

Yes straight dual exhaust, no x or H pipe.

Drivers side has "normal" amount of exhaust smoke.
Passenger side has excessive smoke that gets worse as engine warms up and at higher rpms.
Smoke comes from passenger side tailpipe and back of engine bay/front of cab area on passenger.
It's not safe to drive, the fumes are getting into the cab.
I have to spend some time looking at it and I'll update the post if I find anything.
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
  #12  
Old 01-18-2021, 01:58 AM
MysticRob MysticRob is offline
327 Rambler
 
Join Date: Nov 26, 2019
Location: Boise, ID
Posts: 590
Quote:
Originally Posted by brentwood
My oil and coolant levels aren't noticeably dropping. Smoke doesn't smell like coolant.

Yes straight dual exhaust, no x or H pipe.

Drivers side has "normal" amount of exhaust smoke.
Passenger side has excessive smoke that gets worse as engine warms up and at higher rpms.
Smoke comes from passenger side tailpipe and back of engine bay/front of cab area on passenger.
It's not safe to drive, the fumes are getting into the cab.
I have to spend some time looking at it and I'll update the post if I find anything.

That helps narrow it down. If not smelling of coolant, it also won't be carb related since the effect would be seen out both pipes, so it has to be something related to that passenger side.
Does it smell like unburned gas or oil? You didn't mention that either.

I'll assume oil since you didn't mentioned it misfiring from a bad plug or lack or spark on that side, so maybe the valve seals as jammer said, gummed up rings not sealing a cylinder properly, or something else along those lines.

I had gummed up rings on my high mileage Saturn 4-banger. I poured Seafoam into the crank to loosen all the sludge and deposits, ran that for quite a few miles, and that eliminated the problem for me. Hopefully your plugs give you more info.
__________________
--Rob--
1988 Jeep Grand Wagoneer / Baltic Blue & Tan
2008 BMW 535xi Wagon / Deep Sea Blue & Tan

My build thread:
https://ifsja.org/forums/vb/showthread.php?t=189245
My Howell TBI Install How-To:
https://ifsja.org/forums/vb/showthread.php?t=189877
Reply With Quote
  #13  
Old 01-18-2021, 08:28 AM
wiley-moeracing wiley-moeracing is offline
350 Buick
 
Join Date: Feb 15, 2010
Location: arizona
Posts: 1,372
Are you getting a lot of blow by out of the vents?, If your getting more smoke when warmed up I would look at valve guide seals, the umbrella type get hard and break off with age, viton seals are better but require machining of the head.
Reply With Quote
  #14  
Old 01-24-2021, 02:40 PM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
I tried seafoam in fuel and crankcase oil last week. Also used a bottle of the seafoam for carb/intake.
I ran it for a couple hours since. Can't drive it because it smokes too much.
The smoke is a light grey whitish color.
I pulled passenger side spark plugs... No oil on plugs but they did have a lot of soot/carbon on them.
I tried pinching off trans modulator line...made no difference.
Still no noticeable oil or coolant loss.
I really don't know what to do and can't afford an engine rebuild right now. I may just end up selling it.
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
  #15  
Old 01-24-2021, 04:15 PM
Heep-J4000's Avatar
Heep-J4000 Heep-J4000 is offline
258 I6
 
Join Date: Feb 09, 2014
Location: Schoorl ,the Nederlands
Posts: 354
Maybe not a question that makes sense , but how is the brake fluid level in reservoir?

Maybe doing a compression test also to rule out all possibilities!?
__________________
Jeep "because mother nature hates flat roads to"

http://www.ifsja.org/forums/vb/showthread.php?t=180974

99' Dodge ram 2500 4x4 crew cab 5.9 Cummins ,backup work truck for now
73' Jeep J4000 (named Heep or Desert Dragon) amc 360 V8 converted to LPG with T15/D20 (was my daily work truck for thirteen years and is going to have major overhaul
80' Jeep cj5 350 V8 Chevy/ms420/D300 (a slow ongoing never finished project)

Trucks/car's from the past:
85' Volkswagen caddy mk1 1.6 diesel.
83 Toyota land cruiser BJ42 3.4 diesel.

Last edited by Heep-J4000 : 01-24-2021 at 04:22 PM.
Reply With Quote
  #16  
Old 01-24-2021, 04:22 PM
levelhead's Avatar
levelhead levelhead is offline
232 I6
 
Join Date: Nov 04, 2016
Location: sask. canada
Posts: 200
If the smoke is white you are probably burning coolant. I assume being from NJ you are running a 50/50 mix of water and antifreeze. Go to your tailpipe and have a whiff of the smoke. If it smells sweet that is antifreeze. Your just not burning enough to notice the drop in your level.
__________________
1988 GW (2)
1980 Cherokee Laredo
1979 Wagoneer
1976 J10 401
1977 Wagoneer 401
1977 J10 4 speed
1969 J3000 (2)
1955 CJ3B
1964 Wagoneer
Reply With Quote
  #17  
Old 01-24-2021, 08:32 PM
MysticRob MysticRob is offline
327 Rambler
 
Join Date: Nov 26, 2019
Location: Boise, ID
Posts: 590
Quote:
Originally Posted by levelhead
If the smoke is white you are probably burning coolant. I assume being from NJ you are running a 50/50 mix of water and antifreeze. Go to your tailpipe and have a whiff of the smoke. If it smells sweet that is antifreeze. Your just not burning enough to notice the drop in your level.

From brentwood's post above:
Quote:
Originally Posted by brentwood
My oil and coolant levels aren't noticeably dropping. Smoke doesn't smell like coolant.

Quote:
Originally Posted by brentwood
This reminds me that I plugged exhaust manifold emissions ports back in the summer. The driver side went smoothly. On the passenger side, pieces of inner tube came out with stock bolts. Could this be my issue?

I don't remember seeing that last post, but what do you mean by "pieces of inner tube coming out with stock bolts"?

Again, we're not there with you, but this makes no sense to me, so I'm now wondering if you have rubber or plastic crap burning off in that passenger side exhaust pipe and have an exhaust leak somewhere, seeing as how you said earlier you also have smoke coming from the engine bay near the firewall.

Still scratching my head, but it certainly sounds like the Seafoam is burning off now, what with the white smoke, but without being there it's difficult to help troubleshoot. If it's worse and it's been hours later, it certainly sounds like valve seals or rings are allowing some of the crank case Seafoam into the combustion chamber. Video and pics of smoke and plugs would help. Only you can know the difference between coolant, gas, or oil burning off, but it certainly sounds like valve seals or rings are the culprit.

As mentioned, get a compression and leak-down test done. It may not be all that expensive to fix.
__________________
--Rob--
1988 Jeep Grand Wagoneer / Baltic Blue & Tan
2008 BMW 535xi Wagon / Deep Sea Blue & Tan

My build thread:
https://ifsja.org/forums/vb/showthread.php?t=189245
My Howell TBI Install How-To:
https://ifsja.org/forums/vb/showthread.php?t=189877
Reply With Quote
  #18  
Old 01-25-2021, 11:53 AM
rang-a-stang's Avatar
rang-a-stang rang-a-stang is offline
Administrator
 
Join Date: Oct 31, 2016
Location: Camarillo, CA
Posts: 4,266
My bet is Valve seal(s).
If it is only one side and it's not coolant or trans fluid getting in, that leaves:
Head gasket
Valve seals
Valve guides
rings
Cracked head or cylinder
I guess maybe the intake manifold to head gasket/pan maybe if it is pulling oil up but I am not sure that is really possible

You really need to do a compression/leak down test to determine for sure. If it is your valve seals, I have a set of Fel Pro ones left over from my rebuild and you can have them for shipping. With the right tools you can replace all 16 of them on a Saturday.
__________________
79 Cherokee Chief (passed CA smog check Sept 2020)
(Cherokee Build Thread)
11 Nissan Pathfinder Silver Edition 4x4
09 Mazdaspeed3 Grand Touring
Reply With Quote
  #19  
Old 01-30-2021, 05:48 PM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
Quote:
Originally Posted by rang-a-stang
My bet is Valve seal(s).
If it is only one side and it's not coolant or trans fluid getting in, that leaves:
Head gasket
Valve seals
Valve guides
rings
Cracked head or cylinder
I guess maybe the intake manifold to head gasket/pan maybe if it is pulling oil up but I am not sure that is really possible

You really need to do a compression/leak down test to determine for sure. If it is your valve seals, I have a set of Fel Pro ones left over from my rebuild and you can have them for shipping. With the right tools you can replace all 16 of them on a Saturday.


I'll take the valve seals. Message me with info when you get a chance. Thanks
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
  #20  
Old 01-30-2021, 05:50 PM
brentwood brentwood is offline
232 I6
 
Join Date: Oct 01, 2015
Location: Mullica River, NJ
Posts: 145
Thanks for the replies guys. I'll update when I get time to work on it again.
__________________
1982 Wagoneer w/258, Rusty's 4in spring lift, motorcraft 2100, 32x11.5x15 bfg's *sold*

1972 J4000 Chevy 350, th350, divorced Dana 20, Holley carb, alcan 4in springs, 35in BFGs on 15in slots

1978 J10 golden eagle w/Levis interior, 401and th400, Edelbrock avs2, 32x11.5 falken rubitreks on stock golden eagle wheels
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Stock Cam timing numbers... 360 and 401 Tinkerjeep General FSJ Tech 26 04-11-2013 01:56 PM
401 to 360 Swap What do I need to do? flyusmc General FSJ Tech 6 11-12-2007 08:50 AM
The 401 revisited Elliott General FSJ Tech 20 12-14-2003 12:41 PM
401 info request fdwyer General FSJ Tech 8 04-26-2001 06:18 PM


All times are GMT -6. The time now is 12:28 PM.


Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
corner corner