1986 Jeep CJ7



September, 5, 2010 AT 6:06 PM

Engine Mechanical problem
1986 Jeep CJ7 6 cyl Four Wheel Drive Automatic 171363 miles

My 86 CJ7 has 171K miles, but the engine was completely rebuilt at 169K, so it basically has about 2000 miles on a new engine. The problem: I cannot get the Jeep to start, no fuel is getting to the carb. If I pour gas into the carb, fires right up. I checked the line between the carb and fuel filter and fuel filter to fuel pump, both are clear. I replaced both the fuel pump and fuel filter. If I put gas in the carb to turn the engine for a few seconds and disconnect the fuel line before the fuel filter, no fuel comes out. Assuming the brand new pump works, I guess the fuel line from the tank is clogged? I have over 10 gals of fuel in the tank, any ideas about what is going on or how to handle it? Thanks!


11 Answers



September, 5, 2010 AT 7:20 PM

See my profile. And other CJ 5 and 7 answers, I have given.

You are having a good one!

There are several things that I would try before SNATCHING the TANK!


There are only a few things that could be happening

1) Test your pump---remove the line to the tank and add 3-4 feet of line to the empty connection. Throw the end in a GAS CAN

remove the hose at the carb

a shot of fuel in the carb

Fire him up---ready to shut down


I'm gonna let you start with that---I will continue writing behind the scenes and I will edit the rest into this post you are reading now, you probably will not get an Email, since this will be an edit. So refresh and check here again.I'll be done 20 min. Or so.I'm slow

The Medic


2) If you are pumping.2 more possiblities

A) you have a hole in your "Suction Line" in a rubber hose (pump end, at the Tank end). Or in the steel line inbetweenThe "NELSOMATIC TEST" for this is to Suck on this line (by whatever drastic means you feel) You are checking for fuel to come thru. Nothing but air (gas vapors too). Or you cannot suck the line, because it is clogged in the tank. Or you may have crimp in the hose or steel line.

B) Inside your tank the plastic filter has come off OR is stopped up with many years of crud.

3) ONLY IF THE PUMP pumps---This is a TEMPORARY FIX. Till you get the tank off to fix this right.

Only if you feel you are clogged in the tank

Remove the gas cap (relief) Then at the fuel pump inlet hose. Use an air compressor to blow loose (back toward the tank) what you can in the tank (pick-up tube/ screen) If a second person can hear the air at the open gas cap. You have done all you can do with the compressor.2nd person can hear this well from a DISTANCE. No need to be real close.

Heres where you tell me what your results were with the pump test. BEFORE you do the above stuff.

My course of action may change, with your answer to that.


The Medic



September, 6, 2010 AT 9:30 AM

Thanks Medic, I'll give it a try and re-post. Cheers!



September, 6, 2010 AT 10:37 AM

Glad you responded. Now 11: 40 Eastern.I have to go assist my Mama and Pap. Pap is not doing great. Cancer Treatments. Back by 5: 00 Eastern

Gimme some good news. Other type can still be dealt with.I'm here till you are fixed!

The Medic



September, 11, 2010 AT 1:09 PM

Sorry for the late reply, been working late all week. Well, now I am really confused. I did as suggested; pulled the fuel line from before the fuel filter by the carb, disconnected the line from the tank at the pump and put a new 5' line to a gas can. Pour some gas in the carb, fire up the jeep and no gas. I guessed that meant bad fuel pump (which is new). I put on the old fuel pump which I know works and same thing. No gas. I have a line from a 1gal tank to the fuel pump and the line going out of the pump does not flow gas. What else can be going on here? How long does it take to get fuel from the pump? The jeep is running for maybe 3 sec. Is that enough time? Should I go for a 3rd fuel pump? Thanks!



September, 11, 2010 AT 2:37 PM

Roger, ...........Get your "TANK" a little higher than the pump (just to sorta aid in travel)

You need more run time.......A plastic squirt bottle of gas, with a FINE STREAM....will let you feed it from a short distance.......Careful Flammable!

I forget your Bowl is empty...no prolonged running!

If still, we get nothing pumping.....funnel a liittle down the line.....to maybe "Prime the Pump" (this shouldn't need to happen)

Next with the pump off, using a mirror and flashlight, and a "CRANKER HELPER".........while CRANKING.....observe the Eccentric Lobe (on the cam), that drives the pump.........Does it "WOBBLE" UP and DOWN? (pumping the pump arm if it were installed)

I just got in from a Military Vehicle/ Airplane fly-in

Your turn

The Medic

Check this out, just saw it while ago! A 1985 "258"Diesel CJ-10




September, 14, 2010 AT 7:47 AM

Hey Medic, I should have a free day off work on Fri. I will re-post with my progress. Thanks for the help.



September, 14, 2010 AT 9:17 AM

Hoo-Ahhh. Airborne.

That Lids been up too long already,

This should only happen, when you have a crowd gathered.

So that you can Commence Bragging and Showing Off!

See You Friday

You're buying. Krystals Restaurant, and Krystal Burgers will be fine!

Love You too!

The Medic



September, 17, 2010 AT 11:39 AM

Okay, I replaced the fuel pump (again) and if I use an " external" gas tank (i.E. Beer can full of gas) the engine runs fine. I think the other two fuel pumps were full of sand/grit from the tank. I was planning on blowing back through the fuel line when my buddy brings his air compressor over, but I know that is only a temporary fix. Should I remove the tank and check the filter inside the tank? I looked and it seems that I have to drop the back leaf springs to get the tank out, is that the case for a 86 CJ? If so, I can't do that myself.

Thanks for the idea of using an external tank to check the pump, it worked great.



September, 17, 2010 AT 12:01 PM

Roger. You are tracking well, I just saw you after writing to a Wrangler?

Gonna Keep The Jeep. Please say yes!

Droppng the Tank is not too bad, just time consuming.

Ron, My Neighbor, dropped his Tank (1983) While I " Drill Sargented" him thru it, from a Lawn Chair, 2 days after my surgery to my foot (he's hardheaded and mechanically limited)

Ever consider a Bigger 21 Gallon Poly-Ethyelene Tank?

Ron had not either---till when he pulled off the plastic protection and started Mega Pinholes in his.

I have one tooNICE. Fewer stops.

Want me to send you a " PM" so that we might hook up (via Land Line) and discuss Tank Droppage? Or sorta a " Hotline" when in trouble with the procedure. I've probably dropped 25 or more.


Your Turn

The Medic



September, 19, 2010 AT 10:31 AM

Well, the jeep seems to be fixed temporarily until I can replace the tank. Yay! After replacing the pump (3rd time) I used compressed air to blow back into the tank to clear the line. I think the filter in the tank got blown off, so I spliced an in-line fuel before the fuel pump. The first one I put on was clear plastic (to be replaced with steel of course) so I could see what came out of the tank. Started up the jeep and the filter filled with black fine particulate junk. Replaced the filter and ran the jeep again, and much clearer the 2nd time. My idea is the use the in-line filter as a replacement for the filter in the tank (that I can't get to) until I can drop the tank. It will probably be later in the fall when I have time/money to get to that. Thanks for the help Medic!

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