Jeep dies in high range.

So I'm hoping this is something that is stupid simple or just stupid me... But my jeep doesn't seem to want to drive in high range. It bogs out and stalls unless I really feather the clutch. In 4 low however it drives like a champ... I can let out the clutch without any throttle and it will creep right along... Any ideas? The jeep has a brand new mech fuel pump and filter.

Thanks again everyone, Jake

 

One time many moons ago, I accidently reversed two of my plug wires while working on the engine at night with a flashlight in my mouth. No power in the high end, but in low it was driveable. Figured it out the next day.

 

I haven't touched the plug wires in a while so I don't think that that I my problem, but a vacume leak on the other hand is VERY plausible... I think I need to go through an do a complete overhaul on the vacume system... The jeep has been sitting out for so many years most of the rubber isn't very soft any more... Any one have a diagram or good picture of the vacume lines on a 74 304?

 

I could use one for a 74 232 as I have similar symptoms.

 

Why is that? What would be the difference between the two?

 

Oops. I meant to type "I could use one for a 74 232." I've been told that my 232 is missing some vacuum hoses so I'd appreciate seeing a diagram of how they run. I also have similar symptoms to yours (my CJ tends to want to die in 4H, especially at higher elevations, but runs fine in 4L). I'll edit my previous post. Sorry for the confusion.

 

the two of you can start here...http://oljeep.com/gw/74_tsm/4A-EmissionControl.pdf ps. the whole manual is there id download it b4 its not there anymore things tend to not be permanent on the web

 

Thanks! I've got the TSM downloaded already. Should have thought to look there first.

 

I downloaded the TSM myself today... My wife has something else to hate now... Oh the reading I have to do...

 

Oops double post...

 

If it has points,change them . I once left the key on without the engine running. And the points would bounce at high speed.

 

So I seem to only have one vaccum line... it runs from the driverside of the intake manifold directly to the vaccum advance on the dist. the other port is capped. IN my tsm http://oljeep.com/gw/74_tsm/4A-EmissionControl.pdf it shows the lines running through the spark CTO? Is this just a emission piece or is it something critical? the CTO is in place in my jeep just without any lines running to it... After I replaced the vacuum line and cap my first drive went great i was able to drive in high gear... let the jeep sit for a couple of days went to drive it today and i was back to the same old problem... when I lifted the hood to checl if the lines where still in place I noticed that the fuel filter wasn't filling there is fuel in the tank and a brand new pump as well... also the other day with the engine off I removed the fuel line from filter to carb and there was a considerable amount of pressure... is that normal? could it be another symptom of the same problem? (I have an eddlebrock 1406 4 barrel)

Thanks again, Jake

 

What type of fuel pump are you running? Mechanical or electric?

 

It it a mechanical pump...

 

The spark CTO changes from manifold vacuum to ported vacuum as the engine warms up. This is indeed related to emissions - but it does not have a significant effect on drivability when present.

There is no single vacuum diagram for this year. Instead, you go to the chart on page 4A-45 and note which emissions devices are present on your model and engine. You have two additional columns, CA and NW (nation wide) - pick the one for where your Jeep was delivered. Then you go to the description of each system to see the vacuum connections. Much of the vapor recovery plumbing is shown in Ch. 4.

 

Don't know why you have vacuum straight from manifold to the dist vacuum advance. That would give you maximum advance all the time. Not good.

 

I don't.... I spoke originally out of ignorance... (Refer to previous dunce cap post) my line is running to the carburetor like it should be, it was on the wrong vacume port so the timed vacuum was capped... Switched them around and nothing changed... I went onto edelbrock a web page and found a trouble shooting video that says that my symptoms are probably due to low fuel volume... Which leads to my new problem... Although my gauge is reading 1/2 and my mech fuel pump seems to be functioning ( when I move the arm by hand I get suction and pressure...) I'm not getting any fuel into my filter or even in the lines pre filter... So I think my next step is going to be dumping as much gas in the tank as it will hold and seeing if anything changes... Maybe my gauge is bad... It has been working well since I fixed the ground recently (which is still solid) so I dunno what to think... Any thoughts that are different then mine?

Thanks,
Jake

 

Ok so this is what i have decided... my original problem was caused by a lack of fuel pressure/ dirty carb. (I got about a teaspoon od sand/rustscale out of the carb) i need to replace the aux tank... second problem was caused by no fuel in tank... kinda need that stuff to run. I also had the vacuum lines switched so i replaced them and switched them to the correct possition.

Thanks again everyone,
Jake