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Need help with 84 CJ7 vacuum hoses!!!!

38K views 106 replies 11 participants last post by  Crazy_Jeeper_7 
#1 ·
I am trying to get my 258 4.2L amc engine to run, and the first to tackle are the vacuum hoses and where their correct locations are. When I got the jeep there were zero hoses hooked up, so thought that maybe hooking the hoses up correctly could be vital in this rebuild. Anyone have any diagrams/photos/videos that point me towards the right path. Suggestions and advice are appreciated.
 

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#30 ·
Alright, I've got a hose running from distributor to carb and plugged the rest. Do you think I would be better doing the nutter bypass? Could I still just have one vacuum hose hooked up with the rest plugged?
 
#40 ·
Upon cold start, push the throttle all the way to the floor. Do the choke flaps close all the way?

If it's an electric choke, check for power at the connection to the carb when the engine is running.

What should happen is the choke should close all the way when you floor the throttle before starting. Upon startup, the choke should open only part way. This is called a "choke pull-off", and it should only open the flaps about 1/8 - 3/16" initially. As the engine warms, the choke should gradually open, until the engine reaches operating temps, at which point the choke should be fully open.

Matt
 
#44 ·
Chug,

It may, or may not, be your problem. A faulty choke will make cold starts an adventure, at best.

Usually, you can overcome a bad choke by massaging the throttle while the engine warms. That's assuming the choke isn't stuck closed. If it's stuck closed, then your engine may fire briefly, but it will quickly flood and die.

Matt
 
#61 ·
One of the wires coming off the switch (red w/white stripe), should connect to the choke. The other is for the manifold heater.

Again, gong on memory, here, so someone please correct me, if I'm wrong.

Matt
Actually close but no cigar.

One wire is power coming from the back up light circuit. The other wire goes to a relay for the manifold heater AND the electric choke on the carb.



or in more detail:


Or picture wise:


I think this is the relay socket one of those red wire runs to.


Check here to see if the wire from the switch runs to this relay socket.

Usually though the wire to the E-choke runs through a 6 terminal plug which is usually removed in a nutter hack so you might not have the wire that runs to the e-choke. You might not have the 6 terminal connector anymore. If you do, that's good, just splice in a wire with the correct socket and plug it into your e-choe terminal.

Se my picture up above to what each connection looks like.

Get your test light out and see if you have power to one of the terminals on the oil pressure switch. then start the engine and make sure you have power to BOTH terminals on the oil pressure switch. If your backup lights work, chanses are this e-choke circuit also should work.

If you are not going to run the manifold heater then you just need to run one wire from the switch to e choke terminal.

If you want to hook up the manifold heater then we can address that later.

Usually though I adjust the choke by loosening the e-choke housing.
1. I lay a brick or something on the accelerator pedal to keep the carb throttle open fully.
2. Adjust the housing so it just closes the choke butterfly.
3. remove brick and start engine
4. Adjust idle speed for cold engine and then for warm engine

Not sure of the adjustment on a 2100 though. I'm sure you can find a ton of info on how to adjust the choke and idle on a 2100.
 
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