Fj60 running rough need help!

[SDH]

I was started the fj60 this morning and turned it off immediately after i could hear a vacuum sound slowly dissipate. i could not trace it back to anything? could this be part of the issue? i also blocked off the hose to the brake booster.

 

[Slow Left]

An engine can still run with a vac leak (small ones, like defective Emissions components/switches or hoses)...it might not be able to hold an idle (if the vac leak is big enough, like say, an intake manifold vac leak) or will idle rough. A vac leak lets air in behind the carb (between the carb and the cylinders). Since the air/fuel ratio is set by the carb, by allowing air to enter after that air/fuel ratio is set will change the air/fuel ratio...causing decrease in performance.

And yes, you can hear a large vac leak hissing while the engine is running.

It is possible that that pipe I referred to in the previous image is the source of a vac leak.

Is the hose that runs between the PCV valve and that pipe installed? If not, and the pipe is open to air (not temporarily capped off), then it will certainly be the source of a vac leak, because if you look again at the image, you will see that that pipe attaches to the intake manifold directly below the carb...

You test to see if the idle improves by putting your finger over the end of that open pipe while the engine is idling. If the idle improves, you have proven that it is the source of a vac leak...

 

[SDH]

Hey Slow left!
I couldn't find this post to reply till now!
but it was a manifold gasket leak like you mentioned. also the air rail in the rear had a large crack. the air rail is gone since a desmog, but not it is running to rich to pass emissions.
Although it seems to run/idle very well now!
Thanks again for all of the tips

 

[Slow Left]

Hey Slow left!
I couldn't find this post to reply till now!
but it was a manifold gasket leak like you mentioned. also the air rail in the rear had a large crack. the air rail is gone since a desmog, but not it is running to rich to pass emissions.
Although it seems to run/idle very well now!
Thanks again for all of the tips

Sweet. Glad you got that another problem solved...and is often the case with working through a recently purchased FJ6x, now on to the next problem...!

The hole in the air rail is cause for an exhaust leak, not a vac leak.

The nice thing about installing a new manifold and insulator (the one that sits between the carb and intake manifold) gaskets now is that it rules those out as you go ahead with the either a full desmog or trouble shooting the emissions components before moving on to addressing carb/ignition (dizzy) 'problems'. It would suck to spend a lot of resources on carb/emissions and then burn a valve by running a cylinder lean because of a leak at the manifold gasket, for instance...

You mention that you must pass emissions. What state and what elevation are you at?

Also, when you installed the new manifold gasket, did you get the mating surface of the manifolds planed before reinstalling them? Sometimes they are warped just enough that even with a new gasket there will still be a manifold leak...or when bolted up again to the head, the warp might lead to a cracked intake.

I know you mentioned in your first post of this thread that you set the valves recently. You might consider rechecking (not necessarily readjusting, unless you find some valves out of spec) those clearances, since having properly set valves will improve vac (and performance).

Other thing is where are you taking your vac reading from?

And do you still see the symptom on the #6 cylinder (after installing the new manifold gasket) of increased idle when you disconnect the spark wire at #6 cylinder?

 

[SDH]

Right! i'm glad i was able to dig down and find the root problem as i have heard of burning a valve.
I live in sandy, Ut. elevation around 4450.
No i did not have it surfaced. just checked it with a straight edge. seemed good, but what do i know? (should have took the opportunity to surface it!).
After the mani-gasket i did warm it up and went through the valves also rebuilt the carb, lean drop and timing. @ 4500 what should it be at? 10 BTDC?
i was reading it of of the A/C idle up by the booster hose.
The mysterious #6 has gone away! and the vacuum reading is constant now! few.....
when the hose coming from the valve cover is off and the engine is running i seem to get a lot of dark air(oil?) coming from it?
The compression was ok when tested before the gasket.
what vacuum does your fj60 have?
Thanks again

 

[Slow Left]

I live in sandy, Ut. elevation around 4450.
what vacuum does your fj60 have?

OK, at that elevation I would expect that you should still see around 20 inHg manifold vac.

I see 21 inHg of manifold vac at sea level (with my gauge t'd into the same A/C idle up port on the rear of the intake manifold as you are using). It is considered normal to read 21 inHg at sea level.
You could double check and run the numbers against the chart that Output Shaft posted in that other thread to see what vac loss from 21 inHg you would expect see at 4500'...and then compare that to the 17 inHg you are currently measuring.

Other thing is to go back and recheck for vac leaks at the new manifold gasket...to see what you can find...

Between you, me and MUD, I recently reinstalled a new manifold gasket without having the manifold's planed because I made a similar call as you that they were pretty darn flat...but I'm reading 21inHg vac (as I was before I installed the new gasket), so I'm wondering if something is still off that you are only seeing 17 inHg.

 

[Slow Left]

when the hose coming from the valve cover is off and the engine is running i seem to get a lot of dark air(oil?) coming from it?
The compression was ok when tested before the gasket.

Are you referring to the elbow hose that runs between the rear of the air filter housing and the top rear of the valve cover?

Does the air filter get black really quick?

Does it look like this? see post #59 in this thread:
https://forum.ih8mud.com/threads/do...torque-is-too-much.541922/page-3#post-8127483

Also, here is another thread on blow by:
https://forum.ih8mud.com/threads/fj60-needs-engine-rebuild-suggestions.816628/#post-9345779

But you said that your compression checks out. What are the numbers across the cylinders?

I had some of that dark air/oil coming out of the same port on the valve cover and it was contaminating the air cleaner (but not nearly as bad as the what was coming out of norsk's in the images on the link above).
You might try this:
Before next oil change, dump 1/2 can of Seafoam into the oil in the crank case, run it for ~100 miles then do your oil change (with new oil filter of course).
Also, after oil change, soak the OEM PCV valve overnight in a little plastic baggie with some SeaFoam in it, and reinstall the next day with a new OEM PCV grommet (get the Toyota one, not the aftermarket one) and new PCV hoses/clamps.
A sticky PCV might be causing pressure to build in the crank case and leading to some blow by.

 

[Slow Left]

Did you see a crack in the floor of the intake manifold?

 

[gregnash]

If there is dark air coming out of the back of the vc port that could be blowby which means you are excessively burning oil. Have you looked at your PCV to see that it is functioning properly?
Like SL said, I would run through everything again to ensure that all items are hooked up properly and that you do not have any new leaks. Also, I believe normal procedure on this is to let the manifold get up to operating temp then cool down and repeat process. After a couple repeats you should retorque the mounts on everything to ensure there is no thermal expansion.

 

[Slow Left]

I don't see how you will ever pass emissions if you remove systems like the Air Injection or EGR systems.

Do you still have the OEM Aisin carb installed? I see that you said that you rebuilt the carb...is that the OEM Aisin on you are referring to?

What smog components/systems have you removed?

 

[SDH]

I will check the torque/bolts on the manifold. is there a trick to checking for a leak there?
i tried looking for the Vac chart from output shaft, but no luck. just HAC.
I have not been running to long, but the filter does not seem black or darker.
If i remember right the cylinders where all around 128? one @ 121? I should check again!
there was no crack in the floor thankfully!
pcv valve is a good idea to start with as far as the smoke or blow by.
The AI is no gone and the EGR is also, but from what i do understand the AI is required not EGR (unless the numbers are good)
While at it like gregnash said i'll re-check bolts.

 

[Slow Left]

I will check the torque/bolts on the manifold. is there a trick to checking for a leak there?

Most folks check for vac leaks by spraying a quick burst of carb cleaner (the flammable kind) or starter spray (aka ether) at the interface of the gasket (so for the intake manifold gasket, around where the intake manifold mates to the gasket). If there is a vac leak it will suck in the flammable liquid and you will hear an increase in idle. Be careful not to start a fire, though...

You might also try spraying a shot of starter pray into the throat of the carb primary barrel with the engine idling and the air cleaner off. Does the idle increase or remain steady? If it increases, then that indicates a lean mixture...possibly due to improperly set carb or a vac leak behind the carb.

With the air cleaner off (and even screw out the threaded rod from the center of the carb - the one which you fasten the wing nut down onto the to top of the air cleaner over the rod) and the engine idling, try to 'suffocate' the carb by holding a piece of cardboard (or you hands) over the entire opening on top of the carb...does the engine sputter out and die when you do this?

 

[Slow Left]

i tried looking for the Vac chart from output shaft, but no luck. just HAC.

I was referring to the chart in post #5 by Output Shaft (his MUD name) in this post:
https://forum.ih8mud.com/threads/vacuum-reading.826475/

 

[Slow Left]

The AI is no gone and the EGR is also, but from what i do understand the AI is required not EGR (unless the numbers are good)

Hmmm...do a search here on MUD...there are a bunch of posts by folks in Kalifornia who know what system is responsible for what pollutants...at some point I guess you're going to have to try to pass emissions and then you will know what types of pollutants the engine is emitting and then work backwards from there if you must.

 

[gregnash]

Ok I did a quick look through your thread here and could not find where you are located in CA. If you are in Northern CA or the Central Valley you should look at talking with MudRak (in Sonoma) or Georg @ Valley Hybrid (in Stockton, he goes by @orangefj45) to see if they can give you any further instruction and help you troubleshoot this. My understanding is that CA smog and CARB will do a visual check as well as other emissions tests so if it looks like something is missing (e.g. the EGR or AI) then you will get an automatic fail.

One thing is though that CARB does not allow the sale of any vehicle within the state of Ca WITHOUT documented proof of the vehicle passing smog (if it is to stay in CA). This will give you SOME recourse to go after the owner if they did not tell you it would not pass smog (technically according to the last time I read the CARB laws the owner is liable for any and all repairs of the vehicle to attain a passing certificate).

i tried looking for the Vac chart from output shaft, but no luck. just HAC.

You should not be looking for the word VAC in there. VAC is something that you will get when you are doing your measurements and there are plenty of sources out on the web and on here that tell you what you should be getting VAC wise when at idle, and what the different reads CAN possibly mean.

If i remember right the cylinders where all around 128? one @ 121? I should check again!

Redo your compression test and look at doing a leakdown as well. The compression will give you some information but the leakdown will tell you more. If you truly do have some blowby it could be from worn rings which would show up in the leakdown but not necessarily in the compression test. I would also verify what is acceptable on the low end of the compression scale. I want to say that 124psi is the lowest acceptable for "decent/good" compression for these engines but they should be more in the 130-140 range. I could be wrong though.

 

[SDH]

I was referring to the chart in post #5 by Output Shaft (his MUD name) in this post:
https://forum.ih8mud.com/threads/vacuum-reading.826475/

Thanks!
Looks like max would be around 22.....

 

[Slow Left]

Schematic of the Positive Crank Ventilation (PCV) system as shown on page 3-4 of the 2F Emissions FSM (and see further information in that chapter for testing the PCV valve, etc...):

 

[SDH]

Schematic of the Positive Crank Ventilation (PCV) system as shown on page 3-4 of the 2F Emissions FSM (and see further information in that chapter for testing the PCV valve, etc...):

View attachment 1003813

Thanks SL,
Last night i cleaned and tested the PCV valve seems ok!
Also re torqued the manifold.
Have not started it yet, but will this evening to test vacuum. Hoping it will be up or around 19-21.
I also realized that when i did the valve adjustment i placed the flywheel to the BB not the TDC scratch mark . I will need to re adjust. How big of a difference will that make?

-Gregnash:
I live in SLC, UT. About 4450 elevation.

I think i will get some smaller jets from Kurt at CO just to pass Emissions.

My last #'s where:
RPM HC/PPM CO2 CO
608 478(max 220) 11.68 4.729(max 1.2)
2628 267(max220) 12.01 4.351(max1.2)

 

[Slow Left]

Ok I did a quick look through your thread here and could not find where you are located in CA. If you are in Northern CA or the Central Valley you should look at talking with MudRak (in Sonoma) or Georg @ Valley Hybrid (in Stockton, he goes by @orangefj45) to see if they can give you any further instruction and help you troubleshoot this. My understanding is that CA smog and CARB will do a visual check as well as other emissions tests so if it looks like something is missing (e.g. the EGR or AI) then you will get an automatic fail.

Greg, he's in Utah, not CA...I was recommending that he read through all the Emissions Testing and related MUD threads where the Kalifornians tend to be the experts...

 

[Slow Left]

I also realized that when i did the valve adjustment i placed the flywheel to the BB not the TDC scratch mark . I will need to re adjust. How big of a difference will that make?

I don't know how big a difference it will make. I recall recently reading a thread (I think it was in the 40 & 55 section) where the OP had the same question and the response he got was something to the matter of "it shouldn't make a big difference...", which didn't convince me.

The problem is that by being 7* off on the flywheel (crank), you are 14* off on the cam...so then the question is does being 14* off on the cam put you at a point on the cam lobe where the valve you are adjusting a valve that isn't fully seated?

Instead of trying to prove to yourself either way, it might just be quicker, easier and lower risk to rerun them at TDC (as you mentioned) since you know that you made a mistake and you also know how to correct that mistake...on the bright side, it is another opportunity to master the Art of Adjusting a Valve...