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83 CJ7 Won't Start

8K views 109 replies 10 participants last post by  bob4703 
#1 ·
Ive run into a problem where my 83 CJ7 with a 258 straight 6 wont start. When I crank it it will fire once. Each time I crank it it does the same thing, fires once but wont start. No matter if I pump the foot feed 4 times or not, fires once then nothing. I checked to see if the carb is getting fuel and there seems to be plenty of fuel downstream from the fuel filter. Can someone give me some ideas. Thanks!
 
#2 ·
HI, Pull the air filter housing off and look down the carb while you move the linkage (motor off of course) you should see a good squart down the carb. if not there is no fuel in carb. Tap on the fuel inlet at the carb sometimes the needle and float can get stuck..
Is the choke working?
check ignition switch... barely turn the key just till it kicks the starter.. sometimes the switch well kill the ignition circuit when turned all the way in start, when going bad..
good luck
tim
 
#3 ·
Thanks. The ignition switch only has about 500 miles on it but I'll check. I think the TSM has a test procedure too. I'll check the fuel flow into the carb and the choke. I've had the choke come apart before.

Funny thing is it's been running better than ever. I parked it last night after driving 30 miles. This morning it won't start.
 
#4 ·
Now I'm really confused. I got the Jeep started, but I'm not sure how/why. I checked the carb and choke as pedal2the medal recommended. Both were fine. Then I tried the ignition test he recommended. I had been blocking the wheels and keeping the tranny in neutral as I messed with this for a couple of days. In a senior moment today I forgot to shift to neutral before I cranked the engine and of course the Jeep jumped. No one around; no one or nothing hurt. When I cranked again, in neutral, it started like normal. Any ideas whats going on? Thanks again
 
#5 ·
I'm guessing you have a manual transmission, but your profile not filled out, and mentioning shifting into neutral. Question I have is what starter solenoid are you using? For manual or automatic transmission, there is a difference. Starter solenoid for the auto requires an additional neutral safety switch wired in order for it to energize.
 
#7 ·
Not sure about the solenoid wired for neutral safety switch. Jeep is definitely not flooded. I drove it about five miles today, parked it for 3 hours, now it won't start again. Same issue, fires once then nothing. Just now when I cranked it with the pedal to the floor it backfired slightly through the carb. Could all this be related to a timing problem. Its pretty sudden how all of this started happening.
 
#9 ·
yes I checked the switch. its OK. when it ran it ran well plenty of pep, no missing. I even stopped at a store then restarted. after it sat a couple hours it wouldn't start. After another our it started and i ran it for a mnute and killed it. then it wouldn't restart.

Ill borrow a timing lite. Not sure what you mean by if it moves around.
 
#10 ·
Could be loose wire on the coil, even a failing ballast resistor wire. If it starts in Start and then dies as you go to Run, it would be this area.
 
#11 ·
Sounds ignition related problem with what you describe. Could be number of things with it. Loose wires, coil going bad, ignition module starting to go.

have any spares of any items related to the ignition system?
 
#13 ·
HI, Every time the timing light flashes the timeing mark should be in the same place on dampner. when the chain is bad the well move around.. like sometimes it well be a 8* then next time it flashes it would be at a different number, bad chain.
but it does sound more ignition module than timing.
good luck
tim
 
#15 ·
I get the single fire right as I first turn the key.

I also forgot to say, while the CJ is an 83 the engine is a 77. A PO put a different engine in after he rolled the jeep. I don't have an ignition module on this one. Could be the coil, or that gizmo it has instead of points???

No spare parts. I'll look in the TSM to see of there is a test procedure for the coil.
 
#17 ·
Ah, the good old AM100/prestolite ignition module.... I would purchase a duraspark distributor/ignition module or an hei before spending too much time and money fighting with that thing and the limited parts availability.

Yes there are coil resistance tests to run. Also check coil voltage with the ignition on and also the voltage to the coil when cranking.
 
#18 ·
Even though the engine may be a 77 model, you would think the PO swapped over to the 83 model year ignition system. But of course the 83 distributor would have been used for engine with the computer or MCU that will still work in the non-MCU 77 engine, it just won't have the right mechanical advance.

Can you post some photos of what you have as far as the ignition system goes?
 
#19 ·
Here are some photos. Also, is the a TSM for a 77 Jeep available on line. the one I have is for an 83. it works for most stuff, but my ignition is very different than the one depicted in my TSM.
 

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#21 ·
No, that's not the Presolite system by far. It looks to be what AMC installed in 1983 and is prime candidate for the TeamRush upgrade.
Do you have a picture of the ignition module? It would be on the drivers side inner fender, just below the washer fluid tank, if it is still the stock unit.

The wires going to the coil look suspect. Rust and corrosion on the connections will hinder good voltage delivery. Check the distributor as well for good grounding. It grounds through the hold down clamp.
 
#25 ·
Yup. Just double checked the choke. Tried to start the engine with the choke held open, closed, and just following normal starting procedure. It started once with choke closed. I killed the engine and retried that and nothing. I can get it to start once in a while. It runs smoothly, no misses, plenty of power. Then I kill it and it wont start until it decides to. I'm still leaning towards ignition coil as Ive seen this before on small power equipment engines. Based on an earlier post, it looks like I have an 83 ignition system so the test procedures in my 82 TSM should be valid. Right?
 
#26 ·
Looks like I'm going to replace the coil anyway. A previous response mentioned corrosion etc on the wires and connectors attached t the coil (I live 4 blocks from a bay on the Gulf of Mexico). I decided to clean everything and replace the connectors. When I removed the nut on the post on the forward side of the coil it was good and tight. after I replaced the connector and cleaned everything with acetone spray and a brass brush I found the top threads on this post are stripped and I can't get the nut back on. I also noticed what looks like a blob of metal on top of the post like melted metal from a short. The other post looks similar. Pic attached, is this normal?
 

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