84 Jeep CJ7 Cranks but Won't Run

Tiny
VINNYL
  • MEMBER
  • 1984 JEEP CJ7
  • 4.2L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
Is the CJ Medic there? Here goes:
- 84 CJ7 4.2 with auto tranny and CA emissions (resto'd in 2000 to basically stock)
- Been running rough for a few days, then died while driving (was rougher on hills and bumps)
- Cranks but won't start (good strong new battery)
- Replaced the starter solenoid about 2 mos ago (and freshly grounded it)
- Checked all fuses
- Coil is about 2 yo
- With key in run position I get power at both coil terminals (using simple lighted volt tester)
- Pulled one spark plug and cranked engine with remote starter; got a spark (maybe could have been brighter, but I did get one)
- Noticed that plug was very dry
- Looking into carb and manipulating the levers I can see plenty of fuel squirting in
- No air issues
- I have a voltmeter and am minimally competent in its use
I'm stumped! Please help!
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Tuesday, June 3rd, 2014 AT 1:10 PM

24 Replies

Tiny
HMAC300
  • EXPERT
O your basic ignition checks first like cracked cap coil wire to dist cap then to plug if the spark is weak then ti can be several things. How good are you at testing things? Do you have an ohm/volt meter?
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Tuesday, June 3rd, 2014 AT 4:11 PM
Tiny
CJ MEDEVAC II
  • MEMBER
WHAT YOU GOT VALUE-WISE WITH THIS FIRST PIC?

SEEMS I'M NOT ALLOWED TO HAVE AN AVATAR NOW

LET'S POUR IN 2 TABLESPOONS OF FUEL INTO THE CARB AND TRY IT

HOW DOES IT REACT?

MAYBE YOU GOT WATER RUNNING THRU THE SYSTEM INSTEAD OF GASOLINE-I'VE GOTTEN BAD FUEL BEFORE-I REMOVED NEARLY A QUART FROM "WILLY" A WHILE BACK

THERE IS ALSO THE POSSIBLE AQUA-SABOTAGE FACTOR!

I'VE GOT MORE-KEEP SENDING INFO, EVEN IF IT SEEMS UNIMPORTANT

YOUR TURN

THE MEDIC
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Tuesday, June 3rd, 2014 AT 8:29 PM
Tiny
VINNYL
  • MEMBER
I'm new to the site and I'm not getting notifications when replies hit. That's OK, I know to check the site now.

So here's what I did today BEFORE I saw your post:

- I thought that maybe my spark was weak (see my post above) so I made two changes: (1) I installed a new ballast resistor (a previous mechanic had cut it out of the loop), and (2) I replaced the coil. I checked just about everything else I could think of (disconnected wires, corrosion, etc) - no major issues. Then tried to start. No joy. Great crank but it almost sounds like no gas getting to the engine (to me at least).

I read your post and did the voltmeter test on both old and new coils. Readings for both = 12.36! Based off of what you've told me something is not right. (And Medic I've read some of your other posts - your posts got me on this site.)

I don't have a gas can, so I'll have to do the tablespoons in the carb tomorrow or Friday.

Other background:

- New yellow top Optima (which is great) about 6 mos ago

- You mentioned bad gas. That was my original thought when it first started running poorly. Seems it got really bad after my last fill up from 1/4 tank just the day before she died. But it could it be so bad that she won't start at all?

That's all I have right now. I'll be able to turn to on her again tomorrow after work.

Thanks for your help.
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Wednesday, June 4th, 2014 AT 7:07 PM
Tiny
VINNYL
  • MEMBER
I forgot to mention that I put a new fuel filter on 2 days ago.
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Thursday, June 5th, 2014 AT 4:15 AM
Tiny
HMAC300
  • EXPERT
First ting if the ballast resistor was cut out then it probably fried the coil as it's supposed to cut the voltage down. It may have fried the ignition box as well.
See pic below
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Thursday, June 5th, 2014 AT 6:24 AM
Tiny
VINNYL
  • MEMBER
Hmac,
- I can't see your second image.
- First image is a pic of the distributor. I think the verbiage at the bottom is a procedure to test the ignition module. Is that correct? My ignition module looks kinda like the picture here, except I have a 3 wire connector (not 2) and a 4 wire connector I think. I will try to run this test tonight.

Thanks.
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Thursday, June 5th, 2014 AT 9:07 AM
Tiny
HMAC300
  • EXPERT
Ok've done these all in pdf so you should be able to get them full size or make them larger.
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Thursday, June 5th, 2014 AT 9:52 AM
Tiny
VINNYL
  • MEMBER
Can't make sense of any of these files - each one is cut off badly on the left hand side.
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Thursday, June 5th, 2014 AT 1:59 PM
Tiny
HMAC300
  • EXPERT
Send your email let me see If it comes out better.
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Thursday, June 5th, 2014 AT 3:57 PM
Tiny
HMAC300
  • EXPERT
Test
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Thursday, June 5th, 2014 AT 4:16 PM
Tiny
VINNYL
  • MEMBER
VinnyL0302@gmail. Com

That time the whole write up is there (not cut off) but the quality is so poor its unreadable. I even printed it and couldn't read it. Sorry. I appreciate your perisistence in trying to help me.
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Thursday, June 5th, 2014 AT 4:42 PM
Tiny
HMAC300
  • EXPERT
Ya I sent via two other times onve via email and it locked up everything so i'mnot sure you will get it. You need to get amanual so you can check your control box or go online and look on how to test it as I can't seem to get it to work here sorry. Probably your best bet is online as they problably used that system for a few years.
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Thursday, June 5th, 2014 AT 5:03 PM
Tiny
VINNYL
  • MEMBER
I have Chiltons and Haynes and even a tech manual. I just don't always find them to be very user friendly - guess I'm not very fluent in 'mechanic'.
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Friday, June 6th, 2014 AT 5:25 AM
Tiny
HMAC300
  • EXPERT
Trying again lol. These may enlarge don't know
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Friday, June 6th, 2014 AT 6:22 AM
Tiny
VINNYL
  • MEMBER
Got 'em! Thanks!
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Friday, June 6th, 2014 AT 2:22 PM
Tiny
CJ MEDEVAC II
  • MEMBER
THINK I'M GETTING THE RUN AROUND

I HAVE NOT BEEN NOTIFIED AT ALL ON THIS POST - NOT EVEN ONE OF THE RESPONSES. YES, I HAVE TO MANUALLY SUBSCRIBE TO EVERY QUESTION THAT I ANSWER, TISSN'T SEEM TO WORK ANYMORE

IT'S LIKE MIDNIGHT THIRTY HERE, I'LL FIND YOU THRU "MAKE" TOMORROW, LET ME KNOW IF YOU ARE STILL NOT PECULATING.

I'M CURRENTLY ABOUT TO PUT IN 2 WHEEL CYLINDER KITS, BLEED AND ADJUST THE BRAKES ON "WILLY", THIS IS SORTA A DELICATE OPERATION, TO GET 'EM ADJUSTED PROPERLY. MY PAL AND I HAVE CONSTRUCTED SORTA A "CUT AWAY TEST DRUM" TO HOPEFULLY MAKE IT EZer

THE MEDIC
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Friday, June 6th, 2014 AT 9:59 PM
Tiny
VINNYL
  • MEMBER
I was wondering where you went Medic. I am also not getting notified of posts to this problem. Easier for me to check for updates than it is for you though I'm sure.

Gonna try my meager skills out today on testing the ignition module.

When you get a chance please read through my posts. I tried to answer everything you asked.

Thanks.
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Saturday, June 7th, 2014 AT 8:12 AM
Tiny
CJ MEDEVAC II
  • MEMBER
OK

DID YOU TRY THE SPOONS OF FUEL?

LETS GET A BABY FOOD JAR OR EQUIV, TAKE THE RUBBER FUEL LINE LOOSE AT THE CARB. STICK IT IN THE JAR AND TURN IT OVER TILL YOU HAVE 1/2 A JAR FULL. NOW OUT OF YOUR FUEL CAN, ADD SOME "GOOD FUEL" TO THE JAR. DO YOU SEE THE "GOOD FUEL" FLOATING ON THE "POSSIBLE WATERED FUEL"?

1) 12 VOLTS???? MAY BE TOO MUCH!!!!

2) DO YOU HAVE A STOCK COIL?

3) DO THIS TEST IN MY 1ST 2 PICS - WHAT ARE YOUR VALUES??? (THESE PICS ARE FOR A '77 WITH PRESTOLITE IGN) LETS SEE WHAT YOU HAVE!

4) PIC 3 IS OF THE "ADVANCE AUTO PARTS" IGN MODULE TESTER. (IF I SIZED IT SMALL ENOUGH TO WORK) HAVE THEM TEST IT AT LEAST 5 TIMES IN A ROW! (OR MORE) IMMEDIATELY ONE TIME AFTER THE OTHER. IF IT FAILS ONE TIME, REPLACE IT!. NOW TEST THE NEW ONE THE SAME WAY BEFORE YOU LEAVE THE STORE!!! YES, IT MAY BE "NEW-BAD"!

5) LOOK THIS POST OVER. THERE IS A TEST FOR THE DISTRIBUTOR WIRES IN IT SOMEWHERE IN THE 5 PAGES

http://www.2carpros.com/questions/1984-jeep-cherokee-cj7

CAN YOU SEND GOOD PICS ? - FULL LEFT SIDE - FULL RIGHT SIDE OF ENGINE AND OVERHEAD TOO. HOOD RESTING ON THE WINDSHIELD FRAME-BREATHER OFF OF THE CARB

YOUR TURN

THE MEDIC

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Saturday, June 7th, 2014 AT 8:28 PM
Tiny
VINNYL
  • MEMBER
Success! It was the ignition module: I tested it per Hmac's second 'pic'. Replaced the module and she started right up. Not only that, she starts and runs better than she has in a really long time. Thanks guys!

So I think the ballast resistor being cut out of the loop may have caused or contributed to this. What do you think? I've reinstalled it.
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Saturday, June 7th, 2014 AT 10:56 PM
Tiny
HMAC300
  • EXPERT
Ke I said in one of the previous replies, cutting ballast resistor out probably burnt out the control module or ignition module they aren't meant to operate on 12 volts.
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Sunday, June 8th, 2014 AT 7:40 AM

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