high idle and scary vibration in 3rd gear

[reidfleming]

After a hiatus of around 5 years, I'm the owner of a '81 BJ42 again. Amongst the usual things (transfer seals, rust galore, and an, um, unusual paint job), there are two things that really concern me:
1) About 10 minutes after running, my '81 BJ42's idle begins to climb.
2) There is a scary vibration when I put it into 3rd gear. It seems to ease off as the speed increases. Shifting is smooth, no clunks or weird noises. But the vibration is quite noticable and audible.
Any ideas? Are the two problems related?

 

[AJAEbj42]

If the vibration is only at a certain speed, then it could be a simple as tires being out of balance (lost a weight or something). Although, that I wouldn't characterize as 'scary', so do you think it's engine related or drive-train related?

Post some pics, no unusual paint jobs here! (well almost) .

Welcome to MUD!!

 

[reidfleming]

I thought at first that it might have been the right-rear tire, which turned out to have had a nasty gash on the inside wall, so I swapped the entire set of 33"'s for a set of 30"'s that the previous owner had thrown in, but the condition persists.

I had North Shore 4x4 run a pre-purchase check on it, and the results were: water in front diff, rear diff full and dirty, transfer case leaks, front diff knuckles leak, leaf spring bushings, very rusty gas tank strap, front drive shaft flange broken (wrong bolts), hockey pucks for body mounts, clutch slave leaking & missing spring, cab mounts extremely rusty, vacuum hose at booster worn. They said the engine/transmission/brakes/exhaust were OK.

Pictures forthcoming.

 

[roscoFJ73]

The rising idle is probably the diaphragm in the injector pump,common problem and not too hard to fix.
But check nothing is binding the throttle cable and lever 1st.

The vibration could be a number of things.Bent or out of balance drive shaft,uni joints,worn t/case bearings.
Rusty cab mounts could be amplfying the vibration

After the pre purchase report, I would be doing my sums to see if its worth going any further.
It might be easier to transfer the good mechanicals onto a clean body

 

[reidfleming]

Trying to attach pictures, let's see if this works.

The grey on the roof is mine, in preparation for painting it white (if the rain ever lets up, that is).
The black stuff is... well, nobody's quite sure, the consensus seems to be truck bedliner. It's rough stuff, and a finishing sander only just smooths it down.

As you can see, the left cab mount is pretty bad, and that's an understatement. Without replacing the entire tub, what can be done about it?

 

[amaurer]

Holy front fenders, Batman! Looks like you've got some work cut out for you, what direction are you going with this?

r.e. 3rd gear vibe - any change with the clutch in vs out? what if you shift into a different gear but stay at the same road speed?

 

[AJAEbj42]

water in front diff, rear diff full and dirty, transfer case leaks, front diff knuckles leak, leaf spring bushings, very rusty gas tank strap, front drive shaft flange broken (wrong bolts), hockey pucks for body mounts, clutch slave leaking & missing spring, cab mounts extremely rusty, vacuum hose at booster worn. They said the engine/transmission/brakes/exhaust were OK.

Pictures forthcoming.

Why don't you bring it by our next club meeting (sounds like a BC truck, lower mainland) (coastals cruisers club, see link in my sig) there will be no shortage of enthusiastic opinions!

Got your work cut out for ya, but don't we all?

 

[reidfleming]

The vibration does go away if I step on the clutch. It tones down a lot if I put it into 4th.

I'd attach audio files of the idle speeding up and the sound of the vibration, but it appears that .wav or .mp3 files aren't aren't allowed.

I am indeed in the GVRD. When/where is the next club meeting?

 

[reidfleming]

Ah, OK, 2nd Thursday of May, which would be the 13th. OK, I'll try to make it.

 

[reidfleming]

OK, so now I've got a new diaphragm ($37 + tax, Fred Holmes Fuel Service, Richmond BC), and am now contemplating the task before me. Man, that is in an awkward spot. Do I have to remove the EDIC? If so, where would I find instructions on doing that?

 

[bigbrowndog]

From way over here it sounds like universal joints The rust beetles sure have had a good chew there. Some work ahead for sure.

 

[roscoFJ73]

OK, so now I've got a new diaphragm ($37 + tax, Fred Holmes Fuel Service, Richmond BC), and am now contemplating the task before me. Man, that is in an awkward spot. Do I have to remove the EDIC? If so, where would I find instructions on doing that?

By downloading a free manual from the online manual sticky at the top of the diesel or 70 series forum .
Its also been done before by other members so you need to search under "3B diaphragm"or similar
There maybe some pics under those posts