CJ7 dies while driving without warning - Please Help!

[kenny 84 CJ7]

Hello All,

Thank you in advance for any help you can provide. I have a 1984 Jeep CJ7 with a 256. Just recently I have been driving along, country roads and it dies on me. I can start it back up and it will die again. First time it happened was close to the house. I started back up and made it home. Most recently i made it 5 minutes down road and it started to happen. I was able to limp home.

I think it is a fuel delivery problem. In the last 3 months or so I have had trouble starting it when it had sit for a day or more. I would need to pump the gas (a lot) to prime the carburetor. I thought this was the fuel bowl but found it was not. Decided to just deal with it.

Im not the most mechanically inclined, but willing to try things. I'm leaning towards the fuel pump going bad or the fuel lines having a clog. Let me know your thoughts.

Thanks

Eoin

 

[jdarg]

IMHO you need to narrow down between a fuel and spark issue unless you don't care about replacing parts that aren't necessarily bad. The hard starting issue could very likely have nothing at all to do w/ the random stalling, or it could be directly related, who knows.

First, put one of those clear fuel filters right before the carb and see if it is empty when it stalls. You can get 'em for a few dollars at any parts store.

If it is empty, the problem is between the tank and the carb. Inspect the fuel delivery system. Could be as simple as a loose hose clamp. If your steel lines are rusty, don't even mess with them, just replace them.

If your clear fuel filter is not empty when it dies, its probably your ignition module, maybe your ignition switch, etc.

 

[Torxhead]

I'm thinking possible weak fuel pump or ignition control module. If it is a bad icm, which is located behind the coolant overflow valve it would be warm to the touch after a stall out. A bad fuel pump can be checked with a fuel pressure gauge. There could be other fuel related issues like not getting enough fuel even to the pump, due to various reasons.

 

[hdgapeach]

I'm with Torxhead on this one. Mine did the same thing a few months ago. I installed the Ford DS2 with TFI ignition on mine many years ago. As any good Ford driver does, I keep a new control module in the console for just such an occasion. Anyway, for a few days in a row my CJ would just konk out on me for no reason then, surprisingly just start back up. After about the third time, it didn't just restart. It actually took a few minutes to get it back going. I took that time to swap the new ICM for the one in place and found that didn't help. That's how I figured out the mechanical fuel pump was on it's last leg. The Great One was looking out for me. I was able to get the last 10 miles to the house without it stranding me in the middle of nowhere in the middle of the night.

 

[kenny 84 CJ7]

I'm with Torxhead on this one. Mine did the same thing a few months ago. I installed the Ford DS2 with TFI ignition on mine many years ago. As any good Ford driver does, I keep a new control module in the console for just such an occasion. Anyway, for a few days in a row my CJ would just konk out on me for no reason then, surprisingly just start back up. After about the third time, it didn't just restart. It actually took a few minutes to get it back going. I took that time to swap the new ICM for the one in place and found that didn't help. That's how I figured out the mechanical fuel pump was on it's last leg. The Great One was looking out for me. I was able to get the last 10 miles to the house without it stranding me in the middle of nowhere in the middle of the night.

Thanks Guys, I think it is the fuel pump. I have read a few threads with people talking about switching to an electric pump instead. Is this something I should consider? If so, any suggestions.

 

[thescot]

I personally would not opt for a electric. Typically you will need to add a regulator to lower the pressure. Just two more things to out IMO. Id also make sure its not the filter as its also a potential culprit.

 

[rockhounder]

I'm with Torxhead on this one.

Same here.
What you are describing is exactly what my jeep was doing before I changed out my ICM. You may want to install a new ICM and make sure before messing with the fuel system.

 

[hdgapeach]

1. Mechanical fuel pump is way cheaper and easier to install than any electrical pump system. Less than an hour to install a new mechanical pump and it ought to last for a couple of decades or more.

2. A new ICM isn't expensive and worth the $ to have a spare just in case the operating one takes a dump (a few minutes and you're back on the road). ICMs are finicky little dudes; might work forever, may go out the next time you crank up. 'Bout a predictable as the life of a light bulb!

 

[Hedgehog]

Never really understood the thrill of changing something that almost works forever and is cheap and easy to replace to an electronic fuel pump.

 

[kenny 84 CJ7]

Sounds like it is unanimous, I am going to stick with the mechanical fuel pump. I have ordered both for backups. I will let you know what it was once I have it fixed.

 

[hdgapeach]

While you're at it, go ahead and change out the fuel filter(s). Another cheap and necessary maintenance item that's all too often overlooked.

 

[kenny 84 CJ7]

I just wanted to give a final update. I replaced the ICM with a new one and the Jeep seems to be running better then ever. It starts better that it used to before and so far no issues with it cutting out while driving.

Thanks for all your advice.

-Eoin

 

[Torxhead]

Thanks for the update, icms are one of those "You get what you pay for things". One way to help make it last is to snip off the black wire going onto the distributor and running that wire to the battery ground. That black wire is the ground wire for the icm and is at that location that plugs into the distributor for AMC dealer test purposes. Installing it there is a bad design as it is a long way from being a good ground location and a bad icm ground will kill it. The other two wires are for the distributor pick up coil. The best icm is the Echlin brand made by N.A.P.A. and then the is always the MSD.

 

[hdgapeach]

Cool! That's as easy as it gets. Now, scrape up your spare change and go buy another spare ICM for when "Murphy" raises his ugly head again. I never leave home without one!

 

[dabbrowne]

I agree this really helped me.

 

[tkloth33189]

I have a similar issue. I have an 83 CJ7 with a 1980s 350 Small block. As I am driving it, the Jeep will constantly stall. If I wait about 15 sec it will start back up. I know its not the fuel system. I put a new fuel pump in last Jan and the clear fuel filter is full of fuel. It has a new Edelbrok carb that was installed also in Jan. I pulled the spark plugs out last week and they were covered in black soot which tells me the engine is running rich. I live in Colorado Springs with elevation around 6000 ft. This weekend I replaced the jets and metering rods to make the carb run leaner. I continue to have stalling issues and have no clue where to go from here..... any advice?

 

[Torxhead]

The stalling seems to be from either an over rich carb or an ignition problem, or you could be running out of gas. If it is in the ignition and you have an oem ignition, it should be the high energy type which has a huge distributor cap with a coil on top of it. If so I would guess the ignition control module located inside the distributor or a bad coil, but my first guess would be the icm.

 

[Lumpy Grits]

CK float setting.
Also make sure the ign timing and spark plugs are the correct application for you engine.
LG