72 FJ40 Exhaust smoke/smell advice needed

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Joined
May 4, 2021
Messages
38
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new smyrna beach florida
Hi, my (10/71) FJ40 has a strong exhaust smell and white smoke coming from the exhaust. I changed the oil a couple of weeks and the oil had a strong gas smell to it. There was not a milkshake look to the oil. I performed 3 combustion leak tests and the liquid did not turn colors (it stayed blue). I just replaced the fuel pump and fuel filter. I adjusted the air/fuel screw a bit. I did a compression test and all 6 cylinders were good (140-150). It runs strong and steady at idle. The exhaust spews some nasty brown liquid (photos below) and when I give it more gas while idling it does more liquid, a little alarming how much comes out. I have not driven it a lot so it does sit but always starts. I took out all of the spark plugs and they looked dark at the top.

I’ve read all of the similar posts to get the ideas to do the various things above but don’t know what to do. Am I kidding myself and this is still a blown head gasket? Any other diagnostics I can try? I would appreciate any other advice anyone can offer. As far as I know this is the original 1.5F engine. I’ve owned it for almost 2 years so I’m not sure of history. Thanks
E3BFC8FC-9D17-42AD-9025-5BF0EE5935F8.jpeg
968A6418-879F-4E82-81FD-D9AE757F60B4.jpeg
4BE3467A-EE8B-4389-9122-7CF5FD243998.jpeg
 
Joined
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new smyrna beach florida
Do you notice loss of coolant? How often do you run it for before shutting off? How long do you drive it when you do?
That does look like a lot of fluid, some is ok just a build up of condensation but it should eventually burn off
I haven’t noticed a loss of coolant and it hasn’t run hot or overheated since I’ve had it and I haven’t noticed any coolant on the ground but I was thinking I should flush the coolant and retro look at it and get a baseline. I only run it for 10-15 minutes and have only done short drives. After replacing coolant should I drive it for 45 minutes or so to see if there is any change?
 
Joined
Jul 11, 2013
Messages
1,620
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California
Your carb could be leaking gas into your intake and that will run into your motor diluting the oil. This will ruin your motor. Look inside your carb with the motor off and see if you notice fuel dripping .
 
Joined
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new smyrna beach florida
Your carb could be leaking gas into your intake and that will run into your motor diluting the oil. This will ruin your motor. Look inside your carb with the motor off and see if you notice fuel dripping .
Thank you I will definitely check this out. I had the carb rebuilt about a year ago.
 
Joined
May 12, 2013
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Old Fort N C
Sorry if I missed something, but is this fluid coming out when you first crank it, or after a good drive ( which will dry out the exhaust system) ?
 
Joined
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Messages
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new smyrna beach florida
Sorry if I missed something, but is this fluid coming out when you first crank it, or after a good drive ( which will dry out the exhaust system) ?
It’s coming out after I first crank it but I haven’t driven it to try and dry it out. I let it run for about 15 minutes today and it was still coming out, more when I hit the gas. If it’s from sitting too long would that also cause the exhaust smell? Th ask for the response.
 

JohnnyC

Long ago TLCA# 2231
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UpState Ny, Wells Me
As said above…

Also What type of carb?

Your running a lot at idle … your getting a lot of carbon

The liquid is water … mixing with carbon in your exhaust system… your not running it

The original engine is not a 1.5F … your 10/71 engine originally is an F …. An F155… the only thing we call an f.5 or 1.5f or F and a Half is the 9/73-12/74 F155 … the last F with the improved oil system like that on a 2F

When u last do a full tune up?

Cap
Rotor
Wires
Clean pcv
Clean pcv hose
Adjust timing
Replace points
Adjust dwell
Change air cleaner
Check your valves

Take it out on the highway … get it up to temperature not by idling
 
Joined
Jan 22, 2007
Messages
3,167
Location
Alva, Fl.
This prob. almost seems like there are more than one issue--
1. I f the exh smoke is true white, it could be water--maybe not from the engine, but from the exhaust system-(condensation inside the exh sys--esp if you don't run the rig more than 15-30 mins at a time)--doesn't allow all the parts to get up to op temp-if it has a blue taint--that indicates oil--so do your plugs--run your finger around inside the exh pipe--do you get black greasy residue?(ie if you can wash off your finger and most of the gunk comes off--prob water{condensation}-if you get a greasy residue that won't come off w/water, then oil)----but the compression check is good, so the cylinder seal seems ok. (did you check compression when cold-{worst case})? but the numbers you got look good
2. The gas smell in the oil can usu. only be coming from a leaking fuel pump diaphagm-
-hard to say that the carb is leaking fuel into the cylinders when the engine is stopped(if the engine is still a little warm from running, the atmospheric pressure inside is higher than ambient, so any fuel would tend to stay where it is(in the carb) and not try to go to a higher pressure--plus you have good compression numbers--(if the fuel tank vents are working and the carb float valve is working-fuel will have a hard time leaking into the intake)--even if it did, the heat inside the engine would evap the fuel shortly--again your compression numbers are good, so this cause in my mind can be eliminated.
3. The blown head gasket is not indicated--your compression numbers say no(plus you see no overheating, or loss of coolant)--One possible confirmation check here would be to take off the rad cap, then pull the coil wire and crank for a minute--or just start the engine-see if you get bubbles in the rad coolant.
4. There is a concern here with the condition of the plugs--are all 6 showing these black deposits?, or only one or two?---if all then potential for carb adj--if not, then potential for vac leak at one or more intake gasket connections. (for a cursory check-start the engine and BEFORE it gets hot squirt some carb cleaner in/and around the intake manifold connections to the head, if there is a leak the engine will stumble when any leak sucks the stuff into the cylinder(s).
5. One instrument that is invaluable is a vacuum gauge--it can tell you a lot about the condition of the engine--see attch--
Hope all this helps--
 

Attachments

  • FJ40 vac troubleshooting.pdf
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middlecalf

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Sweet, Idaho
I had a bad head gasket, and my compression numbers were all 140+. And 4 of the 6 cylinders had at least one of the compression rings broken, in several pieces, and one of those cylinders had both compression rings broken and another also had an oil ring broken. There was another build thread were a person had a hole in one of his pistons and that cylinder had 150 compression. Therefore, I’m not a fan of compression tests telling me when things are good (high compression), rather only that something is bad (really low compression). FWTW.

If you’re getting white smoke consistently, not just at startup and warmup, you’re burning coolant. FWTW.

Plan on at least pulling the head.
 
Joined
May 4, 2021
Messages
38
Location
new smyrna beach florida
This prob. almost seems like there are more than one issue--
1. I f the exh smoke is true white, it could be water--maybe not from the engine, but from the exhaust system-(condensation inside the exh sys--esp if you don't run the rig more than 15-30 mins at a time)--doesn't allow all the parts to get up to op temp-if it has a blue taint--that indicates oil--so do your plugs--run your finger around inside the exh pipe--do you get black greasy residue?(ie if you can wash off your finger and most of the gunk comes off--prob water{condensation}-if you get a greasy residue that won't come off w/water, then oil)----but the compression check is good, so the cylinder seal seems ok. (did you check compression when cold-{worst case})? but the numbers you got look good
2. The gas smell in the oil can usu. only be coming from a leaking fuel pump diaphagm-
-hard to say that the carb is leaking fuel into the cylinders when the engine is stopped(if the engine is still a little warm from running, the atmospheric pressure inside is higher than ambient, so any fuel would tend to stay where it is(in the carb) and not try to go to a higher pressure--plus you have good compression numbers--(if the fuel tank vents are working and the carb float valve is working-fuel will have a hard time leaking into the intake)--even if it did, the heat inside the engine would evap the fuel shortly--again your compression numbers are good, so this cause in my mind can be eliminated.
3. The blown head gasket is not indicated--your compression numbers say no(plus you see no overheating, or loss of coolant)--One possible confirmation check here would be to take off the rad cap, then pull the coil wire and crank for a minute--or just start the engine-see if you get bubbles in the rad coolant.
4. There is a concern here with the condition of the plugs--are all 6 showing these black deposits?, or only one or two?---if all then potential for carb adj--if not, then potential for vac leak at one or more intake gasket connections. (for a cursory check-start the engine and BEFORE it gets hot squirt some carb cleaner in/and around the intake manifold connections to the head, if there is a leak the engine will stumble when any leak sucks the stuff into the cylinder(s).
5. One instrument that is invaluable is a vacuum gauge--it can tell you a lot about the condition of the engine--see attch--
Hope all this helps--
Thank you for this info. I’m going to try just driving it for a while first and see if that changes anything. I’m also going to try the bubble test in the radiator but I agree that the head gasket is looking less likely (fortunately). The black on the plugs was on all of them and I’m getting a vacuum gauge this week and will give that a try. Thanks for the vacuum attachment, that will give me some guidance.
 
Joined
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Messages
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new smyrna beach florida
I had a bad head gasket, and my compression numbers were all 140+. And 4 of the 6 cylinders had at least one of the compression rings broken, in several pieces, and one of those cylinders had both compression rings broken and another also had an oil ring broken. There was another build thread were a person had a hole in one of his pistons and that cylinder had 150 compression. Therefore, I’m not a fan of compression tests telling me when things are good (high compression), rather only that something is bad (really low compression). FWTW.

If you’re getting white smoke consistently, not just at startup and warmup, you’re burning coolant. FWTW.

Plan on at least pulling the head.
Thank you, I’m going to try some of the other suggestions but I know what it could be. Did you rebuild your engine or just replace the head gasket, mill it, etc,?
 
Joined
May 4, 2021
Messages
38
Location
new smyrna beach florida
As said above…

Also What type of carb?

Your running a lot at idle … your getting a lot of carbon

The liquid is water … mixing with carbon in your exhaust system… your not running it

The original engine is not a 1.5F … your 10/71 engine originally is an F …. An F155… the only thing we call an f.5 or 1.5f or F and a Half is the 9/73-12/74 F155 … the last F with the improved oil system like that on a 2F

When u last do a full tune up?

Cap
Rotor
Wires
Clean pcv
Clean pcv hose
Adjust timing
Replace points
Adjust dwell
Change air cleaner
Check your valves

Take it out on the highway … get it up to temperature not by idling
Thanks for responding, I’m going to get it out on the road for a good while. The plugs were changed about 2.5 years ago along with cap rotor and wires and I changed air cleaner a couple of months ago. I have not adjusted timing or cleaned pcv hose so I will do that. Thanks again.
 

Skreddy

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Joined
Feb 3, 2020
Messages
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Location
Stanwood, WA
I know lots of guys with muscle cars or when I was into snowmobiling that would start their cars/sleds “once a month” for a few minutes to keep ‘em going. I’ve always thought that was terrible because until it’s up to sustained operating temp, condesation in the exhaust and oil can’t burn off. Seems to cause more issues than it solves (to me).

Just as bad is starting it up and letting it idle for 30 minutes+ without driving. Best way to keep it road ready is drive it on the road. One rambling man’s thoughts.
 
Joined
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Messages
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new smyrna beach florida
I know lots of guys with muscle cars or when I was into snowmobiling that would start their cars/sleds “once a month” for a few minutes to keep ‘em going. I’ve always thought that was terrible because until it’s up to sustained operating temp, condesation in the exhaust and oil can’t burn off. Seems to cause more issues than it solves (to me).

Just as bad is starting it up and letting it idle for 30 minutes+ without driving. Best way to keep it road ready is drive it on the road. One rambling man’s thoughts.
Agreed as usual I’m learning the hard way, thanks.
 
Joined
May 6, 2020
Messages
695
Location
Seattle
White smoke out the exhaust is tell a tale sign of water/coolant getting into the combustion chamber somehow. Typically a cracked head or head gasket. Less likely would be a crack in the cylinder sleeve wall but not out of the question since your compression readings were good.

Stinky gas smelling oil is usually the fuel pump, a broken ring or two, or a fouled plug that has washed out the cylinder wall. How does the oil look now? Still stinky after the change?

You may have two issues here. Like @Skreddy said, firing really any internal combustion engine up and letting it idle to operating temp without putting some sort of load on it will lead to carbon build up. Which then leads to sputtering and just general crappy times. Your example plug is all carbon-ed up but will probably clean up with some freeway speeds. You need to run it through the gears and give it the beans!

Stock exhaust? That pic of the spark plug does not look like it's burning coolant. It's possible you just have like 2 quarts of water condensation sitting in your muffler.

Check the coolant level. Take it for a drive up through all the gears. Check the level again.
 

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