2f cylinders one and two are not helping... (2 Viewers)

[Trollhole]

MAybe a couple of mice made a home in your manifold while you were away and got sucked in #1 and #3 intake. I don't know at this point.


Have you started the engine and verified the valves on those cylinders are in fact moving?

I'm betting valves.

 

[Cruiser_GT]

MAybe a couple of mice made a home in your manifold while you were away and got sucked in #1 and #3 intake. I don't know at this point.


Have you started the engine and verified the valves on those cylinders are in fact moving?

I'm betting valves.

Trollhole - LOL. The valves are moving... seems to me that all we need for the cylinder to fire is fire, oxygen, and fuel. I am convinced that the fire is there and there at the right time. Oxygen (vacuum right?) and fuel seem (to me at least) to be the problem.

Before going any further, I will adjust the valves this evening. I will be one happy dude if that is the problem.

Thanks for the input. After reading through the hayne's manual it occured to me that when the engine was rebuilt, the valves were set cold. It could be that they were never re-adjusted hot.

 

[shelfboy1]

last time that happened to me it was a blown head gasket between 1 and 2 good luck

 

[Cruiser_GT]

last time that happened to me it was a blown head gasket between 1 and 2 good luck

shelfboy1 - what happened? Are you talking about firing on only a portion of the cylinders? Would you share some specifics on identifying a blown HG?

thanks.

 

[Cruiser_GT]

Update - completed valve adjustment. After setting up per Chenoweth's "Valve Adjustment" doc, the valves were not off by as much as I initially thought. Anyway, they have been reset.

The engine seems to be running a bit smoother, but no drastic change.

Read "Vacuum 101" in hopes of finding some clues on seeking out vacuum leaks. What I found was that I am no where near spec at idle. To even get the LC to idle, I've had to set it at around 800 rpm. Even at that the vacuum reading is 9 inches.

Getting out the WD40 and spraying around the intake manifold, I found a hot spot behind the carb (toward the driver's side windshield). Spraying WD40 brought the vacuum up to the 24-25 range. During this burst, I disconnected plug 3 and immediately got a miss.

I also checked along the intake and head for leaks and got nothing. The heat shield prevents me from getting to look for cracks in the manifold.

Do I need to replace the gasket at the carb, or just pull it and the manifolds out for a closer inspection?

Sorry for the long post. Just trying to expose more details.

 

[cruiser88]

start with the carb then move up to the manifold if needed.i bet youits a combonation of both

 

[Cruiser_GT]

start with the carb then move up to the manifold if needed.i bet youits a combonation of both

Cruiser88 - We'll soon see. It will take a couple of days to get the base gasket in.

Are there any tricks to ensuring a good seal between the manifold and carb? RTV plus gaskets?

 

[cruiser88]

Cruiser88 - We'll soon see. It will take a couple of days to get the base gasket in.

Are there any tricks to ensuring a good seal between the manifold and carb? RTV plus gaskets?

i dont use it.just make sure your intake is not warped.you have more chance that your manifold will be warped more than your intake.im not saying its wrong to use permatex on your gaskets,just more personal preferance

 

[Buckwheat]

You shouldn't use sealer on the carb or intake gaskets. If you have to remove them later, it makes it a mofo & if the stuff gets sucked into the engine, you have another leak & maybe engine problems. You can try cinching up the carb base nuts to see if that helps, just don't overdo it & warp the carb base.

 

[Cruiser_GT]

You can try cinching up the carb base nuts to see if that helps, just don't overdo it & warp the carb base.

Buckwheat - cinching helped. Turns out the nut on the firewall and driver side front fender was very loose. I cinched it, but still have a leak. I'm headed down to NAPA now to get a new gasket.

I am now able to set the idle right at 700 rpm. I'll replace all the hoses and the base gasket in hopes of actually getting her to run like she should.

Thanks all!

 

[FJ-40Original]

That's good news!

Replace that gasket and see how she does!



FE

 

[stumpy]

just as a preventative, check for vacuum leaks on the brake booster. not that it will help with cylinders 1-3, but i have replaced one-too-many brake boosters trying to get my leaks sealed up (thanks mace). that might help get better running too. and if your booster is leaking, go get a minitruck booster with a metal hose bib!

 

[Cruiser_GT]

Another question... In checking/replacing the vacuum lines, I tested the dizzy vacuum advance. Nothing. Absolutely no movement for advance (sucking) or retard.

Pulled off the cap and noted corrosion on the internal mechanism. WD40 didn'd fix it.

BTW - my 78 2F was desmogged by a non-LC mechanic. The carb and dizzy are stock to the best of my knowledge.

The question... can I pull the diaphragm and rework the internals (internal to the dizzy)?

 

[Coolerman]

You can clean them up if they are just stuck but if the diaphram is toast then you will need another one.

 

[FJ40Jim]

If the vac pump shows the canister holding vacuum, then the mechanism in the dissy is just stuck. A simple teardown and cleanup will fix that.

If the vac gage is showing the canister is leaking down, then you're SOL. The 78-80 canisters, which are mechanically interchangable, have been discontinued from every source I know of.

my 78 2F was desmogged by a non-LC mechanic.

we need pics of the carb, manifold, dissy....

 

[Cruiser_GT]

If the vac pump shows the canister holding vacuum, then the mechanism in the dissy is just stuck. A simple teardown and cleanup will fix that.

If the vac gage is showing the canister is leaking down, then you're SOL. The 78-80 canisters, which are mechanically interchangable, have been discontinued from every source I know of.

we need pics of the carb, manifold, dissy....

FJ40Jim - I'll get some pics up by this evening if I can (can't find the dang camera). Also, I read through another thread where pics were posted with the schmatic for the correct vacuum setup for desmog. I have not yet verfied everything, but know several connections are not right on my rig.

When you say you need pics of the manifold, are you wanting to see the 2 ports below the carb on the intake (they are both capped off, btw)? Also, are you wanting to see the dizzy with the cap removed (this one is very embarassing since it is all corroded)?

thanks!

Pics are in...
Manifold, carb, and dizzy... if you need more specifics I will have to get them later.

 

[FJ40Jim]

Whatever, just post up some pics so I can make fun of you.

Err, I mean, help you out.

 

[Cruiser_GT]

Whatever, just post up some pics so I can make fun of you.

Err, I mean, help you out.

LOL! o look forward to both.

I edited the pics in above.

 

[FJ40Jim]

The carb is a 1976.

The vac fitting at the top front of carb needs to connect to the manifold vacuum fitting right in front of the carb.

The choke breaker needs to connect to the vac fitting in the side of the insulator underneath carb (phillips head plug).

Need pics of hose connection at dissy and valve cover side of carb.

 

[Mr. Toad]

Check the thing that's labeled as #45 in this picture (credit: SOR). It's one of the few places where a massive vac leak could affect cylinders 1-3.