1979 AMC 304 Rough idle.

[jafo]

Ok. Intake gaskets tomorrow! Yepee! Oil pan gaskets too if time allows.

 

[jafo]

Best CK the new carb gaskets for leaks.
LG

The back two nuts took another half turn to tighten on the carb. Gaskets must have shrank. I'll drive again later.

 

[Hedgehog]

Just for reference I live at ~2800 elevation and my vacuum is just like yours ~18-19. Your engine cutting out doesn't sound like a vacuum problem to me. I am thinking you've got that beast about whipped. Just shutting down sounds like jetting or electrical. I can't remember, how is your fuel pump? You could be sucking it dry. Have you checked your float?

Without question you are getting there.

With all your readings being very close your compression looks fine to me.

 

[Lumpy Grits]

with HH here! When it cuts out-Is it sudden or what??
VERY soapy water in a spray bottle, works very well for pin-pointing vacuum leakage.
At the leak site, you will see the bubbles suck'd in and hear a change in engine pitch/tone.
I would take a wrench to those manifold bolts.
LG

 

[jafo]

Just for reference I live at ~2800 elevation and my vacuum is just like yours ~18-19. Your engine cutting out doesn't sound like a vacuum problem to me. I am thinking you've got that beast about whipped. Just shutting down sounds like jetting or electrical. I can't remember, how is your fuel pump? You could be sucking it dry. Have you checked your float?

Without question you are getting there.

With all your readings being very close your compression looks fine to me.

Well it's evolved from a misfire to no fire it at least it feels that way, it still may be a misfire just not as pronounced. It felt like it just cut out. The key here is it only haeppens under a load while throttling up. I didn't smash the pedal to the floor, It was a gradual increase in throttle until it misfires or cuts out.

I'm still going with new intake gaskets. It doesn't look like a lot of work and it needs to be eliminated as a source. Intake gaskets can leak internally. You'll never see it from the outside. So I'll just put new ones in.

A run down as to what has been done so far. New vacuum hoses. Re routed some vacuum lines. Rebuilt carb, checked float, in spec. Put new gaskets onto spacer plate. New ignition box, new distributor. New vacuum port at brake booster. New vacuum port sensors. Tied back riser. New plugs and wires. Cap and bug looked brand new and had no carbon tracking and no corrosion and very little wear on bug. Moved coil out from under breather.

It could be fuel pump or filter. It may very well be fuel related but I'm with LG. I should be getting more vacuum at idle. I'm also no where near the adjustment on the idle screws everyone else is at. I think that's also a clue. There may be more than one thing going on.

 

[jafo]

OK. I'm about done trying to post pics. I've wasted 15 minutes trying to post pics here. I'm gonna try one more time, if it doesn't work I give up.

Here goes......

Gasket on left came in carb kit. Would have worked if it didn't have the spacer. Gasket on right is for the spacer. If I continue to have trouble with the spacer, I have since moved the coil to where I think I can get rid of the spacer.

Well it finally worked.

 

[jafo]

These pics are of the spacer and various gaskets.

 

[jafo]

I think this pic is the new coil location. Does anyone see anything bad about this location?

 

[jafo]

This is that back pressure sensor that came apart. I have since bypassed this. I went from the COV vacuum sensor directly to the EGR valve. The old routing it went from the COV to the back pressure sensor then through to the EGR.

 

[jafo]

OK. This thing I believe has an inline fuel filter. It's a long cylinder screwed to the port where the gas line goes to the carb. So instead of a barbed tube to put the gas line on, it has this cylinder. I've never seen one like this or used one like this. There was a brand new fuel filter, stock looking, in the glove box. The one that's on there now is roughly less than half the size of the stock looking filter in the box. To me, if there is sediment in the tank, which there probably is, this little filter would plug up in half the time of the stock one. I need to trace the fuel line to see if there is another filter.

Where is the stock filter usually located? I would think along the frame some where? This bigger filter has two ports on one end and one port on the other.

 

[mtnwhlr]

Where is the stock filter usually located? I would think along the frame some where? This bigger filter has two ports on one end and one port on the other.

Mine is to the left of the carb above the intake.

 

[Hedgehog]

Hmmmmmm .... On my CJ the thick gasket goes under the carb. and the thin one goes on the manifold. But I don't have the thick aluminum spacer, mine looks like that one but it's a phenolic (looks like old fashioned Bakelite to me) spacer that is supposed to be there for heat control. Sorry, I'd like to be able to help you more. ........ did you replace your power valve? Also, there are some parts in that kit that don't belong on your carb. I know this because a friend rebuilt his, had trouble with it and brought it to a rebuilder. He found incorrect parts in the carb. The odd part is that nothing other than experience will tell you you've used the wrong combination of parts. A simple change of a rubber gasket and the carb ran like it was new. aaannnnndddd that's all I can do for you, I believe it's a carburation problem. The jeep is just running out of gas.

 

[jafo]

Hmmmmmm .... On my CJ the thick gasket goes under the carb. and the thin one goes on the manifold. But I don't have the thick aluminum spacer, mine looks like that one but it's a phenolic (looks like old fashioned Bakelite to me) spacer that is supposed to be there for heat control. Sorry, I'd like to be able to help you more. ........ did you replace your power valve? Also, there are some parts in that kit that don't belong on your carb. I know this because a friend rebuilt his, had trouble with it and brought it to a rebuilder. He found incorrect parts in the carb. The odd part is that nothing other than experience will tell you you've used the wrong combination of parts. A simple change of a rubber gasket and the carb ran like it was new. aaannnnndddd that's all I can do for you, I believe it's a carburation problem. The jeep is just running out of gas.

I've ran across these type of setups before and all they ever had was one thick gasket underneath the spacer. I've seen the same under stock carbs with no spacer.

I hear ya about.the carb kits. This kit had a few parts that didn't go in this carb. Basically I identified them first thing. I only replaced what I took out. It was a very simple rebuild. Yes, it does have a power valve. Kit came with a new one.

I can totally see your point on fuel starving. That can cause a lean pop and cutting out. It will give me another option to look into.

I do know it's something. I'll find it eventually. It has definitely gotten better, so the parts and work haven't been for nothing. Thanks for the input!

 

[jafo]

Mine is to the left of the carb above the intake.

Drivers side where the fuel line comes up over the intake? If so, the one that's on mine is not the correct filter. I think I'll just get a regular inline filter and put that in. Maybe get a fuel pump also. I have no idea how old these parts are and I'd rather replace them now than take a.chance.on them failing at a bad time. At least I'll know it should be good to go for some time.

 

[Lumpy Grits]

I think this pic is the new coil location. Does anyone see anything bad about this location?

Get rid of the 'horseshoe' connector on the coil. Well known problem area for intermittent miss due to bad contacts. Sound similar to what you are dealing with now??.........
Go to NAPA and get a new coil with screw down contacts.

LG

 

[jafo]

Get rid of the 'horseshoe' connector on the coil. Well known problem area for intermittent miss due to bad contacts. Sound similar to what you are dealing with now??.........
Go to NAPA and get a new coil with screw down contacts.

LG

I've been trying to get this intake done. I had to stop. I can honstly say without a doubt I have, in my very Limited experience, ever seen such a cluster in my life. I've messed with a few iron intakes and this one by far outweighs anything I've seen. This chunk of nightmare has to be about 80 lbs. Then you get to seal with and all metal one piece gasket and sealant. It's a race to get the intake set and then more fun getting the bolts started in precise size holes with no room for error. I had to take the intake back off to reset the gasket. This was nothing like anything I've ever delt with. Wouldn't have been as bad if the intake didn't weight what it does. Man it's heavy. There isn't many spots in the jeeps engine compartment to go to get to anything. I have a fat gut and bad lower back and it taxed both. LOL. So needless to say, this better work, I think it will. Or it's going in to have someone else wrestle that monster.

What I found after taking the intake off was I think the gasket was.compromised. I say that because all the intake runners were wet with oil. They should have been dry but they weren't. So I do think the intake was leaking from inside galley area. Now, after my little adventure today, I'm hoping ad praying it's now sealed. I'm not finishing it until tomorrow so this should let the sealant cure.

 

[Lumpy Grits]

Just a FYI-Old dried out gasoline, looks very oily also.
FWIW: I have had very good luck with Aviation Form-A-Gasket non-hardening liquid, for intake manifold sealing as well as carb base. It's also excellent for sealing all bolt threads the protrude into water jackets like head bolts and such.
The NAPA PN is 765-1210.

LG

 

[mtnwhlr]

Drivers side where the fuel line comes up over the intake? If so, the one that's on mine is not the correct filter. I think I'll just get a regular inline filter and put that in. Maybe get a fuel pump also. I have no idea how old these parts are and I'd rather replace them now than take a.chance.on them failing at a bad time. At least I'll know it should be good to go for some time.

Yes and the return line is there also. After hearing how much the intake weighs if I have to pull mine I will be looking for a aluminum one. But I have yet to even get it running.

 

[jafo]

Just a FYI-Old dried out gasoline, looks very oily also.
FWIW: I have had very good luck with Aviation Form-A-Gasket non-hardening liquid, for intake manifold sealing as well as carb base. It's also excellent for sealing all bolt threads the protrude into water jackets like head bolts and such.
The NAPA PN is 765-1210.

LG

I used the NAPA black rtv. It is what it is. If it has to come back off so be it, I'll just have to redo it. I'm just stubborn and hard headed enough to do this again, I don't like to lose. We'll find out tomorrow who won this round.LOL!

I'll keep that infor in mind. I was going to use this sealer call "the right stuff" until I found it doesn't do well with fuel. So I stuck with rtv.

I've had 3 tanks of fresh gas through the engine, it shouldn't have looked the way it did, it was oil I'm sure. I'll also look into a new coil. What coil would you recommend?

All I need to do is put the antifreeze back in tomorrow and fire it up. That's if I can get up.

 

[jafo]

Yes and the return line is there also. After hearing how much the intake weighs if I have to pull mine I will be looking for a aluminum one. But I have yet to even get it running.

I'm being a little dramatic, but it did tax my butt. I haven't done this work in about 10 or 12 years. I would suggest getting some help in resetting the intake if you use that old anchor. It would be much easier on your back and shoulders.

Thanks for the info on the filter.