Will not start

Tiny
SICHOT
  • MEMBER
  • 1981 JEEP CJ7
  • 5.0L
  • V8
  • 4WD
  • MANUAL
  • 150,000 MILES
Engine cranks but looks like no spark takes place. Changed coil, ignition switch, Ignition Control Module, distributor cap, rotor.
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Wednesday, March 25th, 2020 AT 8:18 PM

40 Replies

Tiny
CJ MEDEVAC
  • EXPERT
Do you have a voltmeter?
Can you tell me what is showing on the positive side of the coil with the key turned to on?
The medic
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Thursday, March 26th, 2020 AT 3:30 PM
Tiny
SICHOT
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Thanks for getting back. I do have a voltmeter. It does not show any voltage when key is turned to on. I have a Ford system and I have been told this is normal. When I turned the key to crank it does shoe 12.9 V. Engine cranks without a problem.
Thanks
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Thursday, March 26th, 2020 AT 5:34 PM
Tiny
CJ MEDEVAC
  • EXPERT
You have one of the three years of CJ's that I consider the best years, that is 1979-1981

How long ago did it run?

Did it run well?

Any modifications from original?

Anything added or messed with prior to this issue, like a coil, removing or turning the distributor, etc?

Even though this is sounding like "ignition issues" of some sort (which we will address real soon) Lets try this below first, as it is an easy test and might rule out fuel as an issue.

Just to rule out a fuel possibility, 2 teaspoons of gas down the carburetor throat, attempt to start. Does it start or try to (spit or pop)? Or does it just do dry monotone over and overs?

I want to do a few tests before we start spending money!

Report findings!

How about well lit pics, left/ right/ overhead of the engine (or more!) With the hood against the windshield frame and the breather removed. Sometimes I can spot problems.

The Medic
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Thursday, March 26th, 2020 AT 6:18 PM
Tiny
SICHOT
  • MEMBER
Thanks for replying back and quick response. Good to know that 1981 s CJ-7 s are considered one of the best. Let me point out that this is a Mexican vehicle. It originally came with 6 in line and now has a V8 Ford. Not sure if after know this, you can still say 81 is a good model =P.
Engine will only crank if I pour some gasoline or starter liquid directly to the carburetor. Engine will just do dry monotone over and overs. I did change the starter because it was not working. After this, nightmare started. Starter is exactly the same it used to have (AutoZone refurbished). I m attaching a quick sketch of my wiring, which by the way is really crappy. Looks like AC did a huge mess. It s definitely after market. It s completely disconnected. I m also attaching pictures of engine, hope they help. I believe it s a TFI (Ignition Control Module mounted directly in carburetor). Several wires are without any connection. No ballast resistor or ignition coil wire resistor. Any guidance is sincerely appreciated.
Thanks,

JC
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Thursday, March 26th, 2020 AT 8:17 PM
Tiny
SICHOT
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Forgot to mention. I also tested compression and found all cylinders okay.
Thanks

JC
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Thursday, March 26th, 2020 AT 8:29 PM
Tiny
CJ MEDEVAC
  • EXPERT
Crank (turns over using the starter).

Start- runs/ busts off.

Tries/ attempts to start- kind of in between cranks and start, it spits and pops and really sounds like it wants to start but does not.

Runs well, but only for seconds before it shuts off.

Which one of these happens when you pour in a little gas?

It was a little unclear in your last reply.

The Medic
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Friday, March 27th, 2020 AT 6:38 PM
Tiny
SICHOT
  • MEMBER
It just cranks (turns over using the starter).
Thanks
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Friday, March 27th, 2020 AT 7:46 PM
Tiny
SICHOT
  • MEMBER
Here are more pictures.
Not really sure if they ll help since as you noticed. Wiring extremely bad.
Thanks
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Friday, March 27th, 2020 AT 8:00 PM
Tiny
CJ MEDEVAC
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I have not abandoned you!

A lot going on over this way and I'm going to "save" your pics onto my desktop and edit them so I can see everything well.

Try this with the key start/on, and a little shot of gas.

Positive battery to positive coil.

Results?

The Medic
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Saturday, March 28th, 2020 AT 8:58 AM
Tiny
SICHOT
  • MEMBER
Did what you recommended. Please refer to picture. I m attaching two videos after pouring some gasoline. One showing result of positive battery to positive coil. It does run! Horray! But only for few seconds. = (
Second video without wire connected from battery positive to coil positive.
Does this mean starter relay is not working?
Thanks Mr. Medic for your help and no worries. I m patient but really anxious to have my CJ7 running again. Hehe =D

JC
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Saturday, March 28th, 2020 AT 2:46 PM
Tiny
CJ MEDEVAC
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On 2nd video,

Did you spoon in some gas for that test or did you leave it alone from test 1?

One more time- for giggles- key "ON" test positive side of coil with voltmeter.

We are trying to determine whether it's a fuel issue or an ignition issue.

I have further tests once I kind of know which is lacking.

I have you jumper from the battery and add the fuel. If it ran (at all) I knew it would motivate you! You would know it is still alive and you would not resemble my pic.

Results this go 'round?

The Medic
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Saturday, March 28th, 2020 AT 4:50 PM
Tiny
SICHOT
  • MEMBER
LOL
It s a live! =D
On second test I did pour more gasoline and engine just crank.
Did the voltage test again, and when key is "on", no voltage at all in coil positive (voltmeter s black probe in negative from battery and red probe in positive coil). Cranked engine and registered voltage in coil +.
Ignition problem? =S
Thanks

JC
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Saturday, March 28th, 2020 AT 8:26 PM
Tiny
CJ MEDEVAC
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My Gosh!

Did a raccoon arrange your wiring?

Still need to decide which way to go when you post your new findings (insure you remove the temporary battery/coil jumper wire when you take your reading!)

A few questions below from looking at your pics.
First) heater (for my own learning)

Second) is this wire touching and shouldn't?/ Others soldered or twisted?

Third) PCV hole visible/ I do not see a fresh air hole in either cover (where is this engine getting fresh air for the PCV?) See my pictures 4 and 5) Even though it is a inline 6, it gets fresh air into the engine cavities as the PCV sucks out the bad gasses and water vapor. (Send pic of the fresh air hole)

The Medic
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Saturday, March 28th, 2020 AT 8:36 PM
Tiny
CJ MEDEVAC
  • EXPERT
Pic 1) wire originating from no where?

Pic2) disregard everything except the explanation of "I" (this is a diagram for a stock 258 6 cylinder)

pic 3) My 1977 ignition switch, my steering does not tilt. Located on the other side of the firewall, it sits on top of the steering column.

If it comes to it, Key "on" test the metal terminal that the marked wire runs into (if it's dead- the switch is most likely bad). It also might be "slid" in it's anchor holes and just be out of adjustment (not synced to its proper position)

For now, the easiest thing to try will be start at the positive side of the coil and start tracing that wire back. Look for breaks, connectors loose or bad, fuses? Etc. That wire will eventually wind up at the ignition switch.

That "jumper" we temporarily stuck on just bypassed the ignition switch- happy hunting!

Keep us posted.

The Medic
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Saturday, March 28th, 2020 AT 9:29 PM
Tiny
SICHOT
  • MEMBER
LOL
I think a raccoon would have done a much better work! =D
Answers to your first reply:
1. Yes, these are from heater. I was not able to capture too much from other side of firewall. Second picture shows hoses from the aftermarket A/C (I m attaching also picture of the A/C console).
2. Wires do not touch. They are soldered (picture 3). I do have twisted wires on wire that goes to solenoid located on the left side of the carburetor (picture attached). Not sure what this is for. The next picture is showing connector that the wire for crank has. You can also see on this same picture slightly to the left an open wire which I indicated on my initial "wire diagram" (right next to the choke - green-).
3. The next picture shows the PCV hole. I m also attaching two pictures showing open outlets (or inlets?) From rear and front of carburetor. Hope the last picture also shows a hose that goes from brake booster. Not sure of its purpose.

For your second reply, here are my answers:
1. It goes to the "I" terminal in the starter relay.
2. I ll review your diagram. Thanks for sharing
3. Ignition switch is the same as yours mounted in the steering column. Did validate positions matches key position (e.G. Accessories, ON, etc.). Removed it to ensure this and put it back all the way to the accessory position. Once I place key on accessory voltmeter of dash indicates 12V. I ll double check the voltage on the ignition itself when key is "ON".

I ll trace the ignition once it gets to the fuse box and will get back to you as soon as I m done (hopefuly before day ends).
Sincerely appreciate all our help!

JC

PS1: Jumper was removed.
PS2: I m seriously thinking in removing OE s harness and replace it with Painless 10110 kit. Yesterday I compared this kit with the harnesses in place and I think there is minimum differences (e.G. Indicator for wipers in kit has only two wires and also switch harness is different). This was a gift from PO. But hey, CJ used to run fine. Want to make it run before I start this adventure.
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Sunday, March 29th, 2020 AT 10:04 AM
Tiny
SICHOT
  • MEMBER
Confirmed, 12V when key has "on" position and power from battery cable constantly has 12V, both in ignition switch.
As shown in diagram (first picture), tracing back from coil positive (+), wire will join blue wire that goes to relay. Where these two are joined, a third cable that comes from the choke is joined (brown cable). Out of this relay we have a black and yellow cable not connected to anything, a red wire will come out as well and join to a purple wire that comes from voltage regulator. Once joined it goes to the positive of the battery (red wire). From this relay, there s another white cable that goes to balast.
There s no wire going to the ignition switch from coil positive. The crank wire is the only one going from fuse box to "S" in the starter relay.
First picture shows the whole "diagram". Second picture shows union of choke (brown), coil (red) and relay (blue). Third picture shows top view. Fourth picture is another view of "Bosch" relay.
Does the "I" in starter relay needs a wire to get to the fuse box?
Not sure what s the function of the relay (Bosch) but it s sure preventing for Coil (+) to be connected directly to (+) in battery (jumper that you suggested at the beginning).
Thanks for your help. =D

JC
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Sunday, March 29th, 2020 AT 5:25 PM
Tiny
SICHOT
  • MEMBER
Forgot to mention that I removed all electrical wire insulating tape just for better appreciation. I ll for sure place it back once we are opening champagne celebrating. =D
Thanks

JC
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Sunday, March 29th, 2020 AT 5:36 PM
Tiny
CJ MEDEVAC
  • EXPERT
I have found a few issues in your pics that may affect the way your engine is running.

I need a little time to assemble something for you.

Meanwhile! Here's some other stuff.

Any idea what that heater came out of?

You may be up to par with this (or not)

This feller goes over things well, there are other videos near this one.

https://www.youtube.com/watch?v=kjSGCSwNuAg&t=1232s

Crimping your stuff correctly and using proper stake-ons (such as un-do-able connectors that fully conceal the metal when it's joined together) This will prevent accidental shorts onto metal stuff (ground)

Wires that are unused and the wire end just dangles might be protected from a short by simply squeezing one end of a butt splice onto it. The other end of the butt splice will connect to nothing. Like in pic 1.(sorry, it was hard to construct this one)

More pics coming soon!

The Medic
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Sunday, March 29th, 2020 AT 5:37 PM
Tiny
SICHOT
  • MEMBER
As always, I appreciate your help and advises! Great job on the picture showing how I should protect unused wires! =D As clear as water. I ll for sure work on this once nightmare is over.
I do have some tools and connectors that will for sure help me with this.
Thanks for your awesome help!

JC
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Sunday, March 29th, 2020 AT 7:32 PM
Tiny
SICHOT
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Forgot to mention, awesome video! Thanks for sharing.

JC
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Sunday, March 29th, 2020 AT 7:33 PM

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