1984 DJ5 revival

benXJ

Well-Known Member
Joined
Dec 5, 2005
Location
Raleigh NC
This will be super slow and not updated that often, but here we go

Picked up a complete and mostly rust free 1984 DJ5 with the carbed AMC 2.5 and 3 speed auto (904?). This is the last year of the DJ, and all of them are 2wd and RHD. No PS or PB, or really anything at all. The simplest truck I own now.

It was not used that hard and it appears 99% complete and not effd with

But it did sit a while and needs refreshing:

New tires (14" now, may go to 15")
cranks and idles, but dies immediately when putting in gear
drum brake wheel cylinders are leaky (all the way around)

Before I do too much to it, i want to make sure it will run, shift and stop reliably.

#1 issue: Anyone in Raleigh still rebuild carbs so I know where my baseline is.......?

I see shops online to mail it out for a rebuild, but would prefer local if possible

Thanks!

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I've been looking for a knockoff 1bbl for this engine that would minimize the emissions nest and emissions computer, but haven't seen anything?

The 2bbl from the 4.2 six is not a direct swap, from what I see
 
the more I look, I beleive some 1BBL carbs for Carter YF setups on older ford sixes will work

since I do have all the emissions and computer stuff in tact and it 'looks' ok, I will be rebuilding the stock carb first before I throw on a Chinese one and gut 90% of the emissions, never to go back on again most likely
 
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Got the carb rebuiilt, and it does better. Not great, and still wants to stall when letting off the gas pedal. But it goes, and shifts through the gears. So a win. Engine is strong and no smoke what so ever.

New rear brake cylinder and now it stops.

Engine is strong and no smoke what so ever. I wanna keep the engine but make it more simple.

However, need advice.....I want to take all the emissions off, all I want is a carb, coil, and distributor. (may keep the charcoal canister for fuel smells, but only after I can depend on it to run)

Can I get some advice on how to do that? What carb? I've heard that old school YFs will work, but no proof.

What about the distributor? Its somewhat computer controlled now (has vac advance too, but is it working?), but can I make it just vacuum controlled? Or can I use a 'non emissions' 4 cylinder distributor from something else and swap the gear? Maybe get my factory dizzy 'rebuilt' and make it non-computer controlled? Someone locally can do that?

This engine was never made pre-emissions, so I can't use factory jeep parts I don't believe

(or just go straight to fuel injection, but that is more $....still thinking about it)

Thanks!
 
Did the Nutter Bypass (should have done that earlier)
and it runs better
the biggest issues at the high level were due to the cat converter air pulse system really caused it to run rough and just die randomly.

gonna give it a long drive this afternoon to see if it's really 'fixed'
ordered some add-a-leafs to keep it off the bump stops and new shocks

tires next
 
its not perfect....it wants to 'miss' and when accelerating from a stop when warm, but idles fine and the exhaust smells normal

gonna clean up the now un-needed emissions mess this weekend and play with the timing.

there is talk of adjusting the fuel mixture screw after doing the Bypass, but I hope to not have to do that

suspension parts are arriving.....
 
Might be running lean under power, but the carb was 'professionally' rebuilt a month ago and has the factory jets in it.

I have read that the fuel mixture screw may need to be adjusted after the Bypass, but not really sure why.

Timing chain is original, the motor has never been opened up as far as I can tell
 
benXJ said:
I have read that the fuel mixture screw may need to be adjusted after the Bypass, but not really sure why.
Click to expand...
The way I understand the bypass that you have done… the carburetor fuel mixture used to be controlled by stepper motors turning some adjusters. After the bypass, the computer is no longer controlling that adjustment.
So now you must adjust the mixture manually to make sure it is set correctly, the same way you would on any non-computer controlled carburetor.
is that right?
 
That is correct for the 4.2 6 cyl, as that carb has the stepper motor.

I have the AMC 2.5 (4 cylinder), which is a different 1 barrel carb

My carb does not have the stepper motor, but does have a fuel mixture screw.

I'm doing some other small steps beofre I start tweaking with that
 
I have not hooked the vac gauge to it yet

I have rotated the dizzy some to smooth the idle out, and adjusted idle speed

would I adjust the vacuum by the mixture screw or by rotating the dizzy?

or both?
 
All of the above. Turn mixture screw for max vac, correct idle if necessary, then play with timing. Do you have a factory spec for timing?
 
Yea, there are well documented timing specs.

I messed with it a bit more over the weekend, and it seems OK. I adjusted the timing to get it to knock under load, then backed off so it only knocks if I really get on it, which I won't be doing usually.

I had to stop due to a sticking front right brake....I'll get that fixed and then back to drivability things.

Adjusting the idle mixture screw didn't really seem to do much, by ear anyway.

It still has an annoying miss/stutter every 4-5 seconds. And will want to almost cut off when coasting through a turn and then slowly getting back on the throttle.

I looked at the accel pump operation while at idle, and a nice stream of gas shoots in when blipping the throttle....so that seems to work.
 
i didn't go all the way in (thats what she said)

just rotated it CW and CCW 3-4 turns each way, no noticable difference.

No vacuum leaks.. It idles fine, even and no surges or high idle, and I've actively made sure leaks have not been there, as its an easy thing to do

is all the way in full lean?
 
Hooked a vacuum gauge to it at the lowest spot I could find near the carb. No vacuum nipples on the intake manifold that I see (or could easily get to)
.
Seems to be ok? 18ish in-hg steady. I adjusted the mixture screw all the way out while idling and it made no difference to how it was running or the vacuum #. So I put the idle mixture screw about half way in....best guess.

Still wants to 'miss' every 2-3 seconds while I ramp up the RPMs at idle. Around 2500 rpms.

How can I make my distributor rehabbed to make it only vacuum advance? Do I need to? Is there a non computer controlled dizzy that can be retrofitted? The dizzy is the only thing that still has legacy emissions stuff hanging around.

Thanks!
 

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Something is wrong in the carb if the mixture screw has no effect.

Distributor should have mechanical advance and vac advance, need both. Not sure on computer stuff there.

Have you tried the dollar bill test over the exhaust? Just to rule out burnt valves.
 
You can lock out the mechanical advance on 'most' distributors, but it's not going to be happy at either high or low RPMs depending on where you set it.

Yea something is up. If you turn the screws out it should start to run too rich and stumble, in too lean and stumble. It shouldn't even run anymore if you turn them all the way in. If so then it's pulling fuel from somewhere else in the circuit (I wrote the opposite previously).

It sounds like you need to tune the accelerator pump if it's stumbling when you hit the gas.. I don't know much about those Rochesters if that's what you have.

Also just saying

 
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