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1984 CJ7 Starting Issue - Need Help

1984 CJ7 Starting Issue - Need Help

kenny 84 CJ7

Jeeper
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Location
Charleston SC
Vehicle(s)
1984 CJ-7
Second Post Ever

The Facts:

I have a 1984 CJ7 that is basically stock in the engine compartment. From what I can tell the previous owner replaced the alternator, fuel pump, distribute, spark plugs.

The Problem:

When I go to start my Jeep it struggles to start unless I engage the electric choke or give it gas while it is turning over. This happens every time except for times when the jeep had been recently running and then restarted. Battery reads at 12v. Im thinking its something to do with the fuel system/carb. I have seen other threads of people saying that the fuel is draining out of the lines while the car is sitting, but they were all on on non-stock carbs. My jeep is basically all stock.

I am not a huge engine head, but willing to learn and do the work myself. Any ideas or questions just write me back. I posted two pictures of the engine compartment along with this just in case you guys see anything i dont.

Thanks

Eoin

Jeep Air Intake 1.webp

Jeep Air Intake 2.webp
 
Something to add to my post would be that once the Jeep starts it runs well, but sometimes it will idle a little rough if it has not been run for a few days. This goes away once I have been riding for a while or got up to speed. Basically, when I come to the first stop sign near my house the car rocks a bit, feels like it is just idling badly.

Not sure is this can help.

Thanks
 
Something to add to my post would be that once the Jeep starts it runs well, but sometimes it will idle a little rough if it has not been run for a few days. This goes away once I have been riding for a while or got up to speed. Basically, when I come to the first stop sign near my house the car rocks a bit, feels like it is just idling badly.

Not sure is this can help.

Thanks

I'm kind of a newb...

But maybe its the carb (needs adjustment), Air filter needs to be replaced -or the little air breather in the carb housing, or timing needs to be adjusted, or gas not reaching carb? :eek: -Or vacuum leak? Or ignition problem... :rolleyes:

Or none of the above... :o

Perhaps one of the veteran jeepers will chime in too. :cool:
 
I'm thinking the fuel has evaporated from the float bowl since the last shut down. I recall seeing a float bowl vent on the top of the carb that has a door on it. You might check this an its operation, it is operated by vacumn. There is info about this on page B-248 in the M.R. 252 factory service manual:
http://www.civilianjeep.info/84-86FSM/CJ-FSM-84to86.pdf
 
I will have a look at this flow bowl thing, that sounds like a good start for something that could be wrong. The book is not too extensive or newb friendly so I will do my best to check it. Any tips?
 
Check orientation of your fuel filter. One line in, two lines out. Bottom line should go to carb, top line goes to return line. If the top line is going to the carb, the bottom line will allow the fuel to drain back into the tank.

I recently had the same problem, took my carb off and rebuilt it, and then discovered my fuel pump was on its way out (diaphram in pump was going bad, allowing fuel to run back down fuel line to tank). New fuel pump- problem solved.

Before you throw parts at it, check your fuel filter, and then make sure your clamps are all snug on your fuel lines from fuel pump to filter to carb.
 
On a cold engine, the choke should always set, even if it's 90 degrees outside. There is a starting procedure for carbed vehicles.

1. Before you crank the engine, step on the gas pedal once. The sets the choke. (three times if it's really cold out)

2. Crank till it starts. After it starts, step on the gas pedal again. This sets the second step of the fast idle cam.

3. If the electric choke is working, it will eventually open (a few minutes) disengaging the fast idle cam and returning to curb idle speed.
 
Check orientation of your fuel filter. One line in, two lines out. Bottom line should go to carb, top line goes to return line. If the top line is going to the carb, the bottom line will allow the fuel to drain back into the tank.

I recently had the same problem, took my carb off and rebuilt it, and then discovered my fuel pump was on its way out (diaphram in pump was going bad, allowing fuel to run back down fuel line to tank). New fuel pump- problem solved.

Before you throw parts at it, check your fuel filter, and then make sure your clamps are all snug on your fuel lines from fuel pump to filter to carb.

Well, I had a look at it today and it does look like the lower of the two lines coming off the fuel filter is the return line. Is this simply a gravity issue of how it is orientated, or does the fuel filter have designated outlets for carb and fuel return?
 
On a cold engine, the choke should always set, even if it's 90 degrees outside. There is a starting procedure for carbed vehicles.

1. Before you crank the engine, step on the gas pedal once. The sets the choke. (three times if it's really cold out)

2. Crank till it starts. After it starts, step on the gas pedal again. This sets the second step of the fast idle cam.

3. If the electric choke is working, it will eventually open (a few minutes) disengaging the fast idle cam and returning to curb idle speed.

That all makes sense, but what defines a cold engine. Im having this issue even if i had been driving the car 2 hours before. Im trying to keep track of time between starts that require me giving it gas to start.
 
The return line should be at the top or 12 o'clock position. When you go to start a cold engine, remove the air cleaner, look down the throat of the carb, open up the throttle and look for two streams of fuel squirting down into the carb. This would indicate that the accelerator pump is working and that there is fuel in it at least. This is what gets the engine started, then the fuel in the float bowl takes over, if there is any fuel in there. You might at this time put about a teaspoonful of fuel into the carb and then try to start it. It will take some research and you will have to eliminate the possibilities. It might even be fuel draining out through a leak in the accelerator pump as another guess. Years ago when I had this issue it was solved by installing an electric fuel pump to fill up the float bowl prior to startup. The cheap fuel pump eventually died and I installed fuel injection.
 
That all makes sense, but what defines a cold engine. Im having this issue even if i had been driving the car 2 hours before. Im trying to keep track of time between starts that require me giving it gas to start.

A cold engine is one that sits overnight or anytime the engine returns to ambient temperature.

If you say, drive around and park to get groceries and the engine sits for around a half hour to a couple of hours, you will need to give it some gas to start. Pretty normal.
 
the problem:

when i go to start my jeep it struggles to start unless i engage the electric choke or give it gas while it is turning over. This happens every time except for times when the jeep had been recently running and then restarted.

What you describe is pretty much how it was when I would go to start my jeep. It would then stall at the first few stop signs on the way to the store. It had been sitting in the garage for years and I only started it up to run to the store maybe 8 times a year or so.

I was told that possibly my carb had a layer of shalack in there from sitting and using old gas, etc. So I cleaned out my carb and installed a rebuild kit. I didn't notice any big change really.

I also had an intermittent thing where the engine would kill for a split second from time to time. So I replaced my Engine Control Module. After I changed out the ECM, my jeep started up immediately. I then did a good tuneup and since then she starts right up and keeps running smoothly. (no more intermittent shorting issue either)

You may want to give the ECM a look. It was definitely the problem with my jeep.

Good Luck!
 

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