Jeep only starts with I jump the solenoid

[furweln84]

Hi, Im new to this forum but not to Jeeps. Ive been out of the Jeep world for a while and all the forums I used to frequent seem deserted - Jeepboard, Jeepsunlimited, etc.

I recently bought a 83' CJ7 Survivor that Im bringing back up to my standards. It had an old weber and a major exhaust leak that I fixed with an mc2150, headers, and a remflex. I finally got it to where I could start it after the carb and stuff were replaced and the only way I can get it to run is by using a test lead to jump the "S" side of the solenoid from the + battery post. it will start up great and run solid for a few minutes then it shuts off.
When I try to start it with the key (new ignition cylinder, old ignition switch) it just cranks and cranks and only barely sputters when I shut the key back off. It also only shows a spark (coil and plugs) when the key is being shut back off, no spark during cranking.
New coil, it also has a nutter the previous owner did.
Im thinking the ignition switch behind the dash is bad, which is what lead me to jump the solenoid. Or maybe it is the solenoid going bad?
Would either of those cause the engine to shut off after a few and not start with a key?

It was hard to start before the new carb and stuff too, so Im thinking whatever is bad finally crapped out.

Thanks for any help, Ive done my fair share of Jeeps from CJ's to XJ's to TJ's but its all coming back slowly and electrical stuff has never been my strongpoint.

 

[Torxhead]

Your primary problem seems to be the engine shutting off. It can shut off due to too much fuel or not enough. Like a bad fuel pump that would be not enough fuel or a poor carb float setting that would make it run rich and flood out.

 

[mtnwhlr]

I wonder if the Ignition Module is going out?

 

[harleydragon]

the ignition switch may need adjusting or possibly replacing..if it has a tilt wheel,try moving it down and try it..that will work sometimes if it is out of adjustment just a little..
not firing until you let off the key could be the solenoid itself..
check the big electrical plug going to the column to make sure it's plugged in good also

 

[furweln84]

Thanks for the replies. Its a non-tilt column. The lower electrical harness is nice and tight. The shutting off thing could be the new carb out of adjustment, but I havent had it running long enough to mess with. When it runs, it actually runs well. I just need to figure out why the key wont start it...Would a bad solenoid let it run and then something closes and shuts it off after a few?
Is there any adjustment in a non-tilt ignition switch? Do they just go bad or is it more of a terminal corrosion thing where it only works sometimes?

Oh and when it runs for a few then shuts off its at idle. I can rev it up and it wont flood out. It runs smooth at idle but it will just shut off after a couple minutes.

 

[harleydragon]

yes,you can adjust the switch...shutting off only at idle is probably a carb problem..I usually set the idle mixture screws at 1 1/2 turns out..it should run good at that until you can fine tune them with a vacuum gauge

 

[Torxhead]

I think you should start with a fuel pressure check, then make sure that the float bowl is filling up correctly and set to the proper level.

 

[furweln84]

Ill keep working on it and post up more or a fix if/when I figure it out. Thanks

 

[furweln84]

Replaced the ignition switch on top of the column and the ignition solenoid at the same time and it starts like it should with the key. Now I just need to adjust the carb so it will stay running. Its a new MC2150 it fires up easily but shuts off after a few minutes at idle. I think my vacuum lines are not 100 percent routed right or the mixture screws are off some. Im going to put a vacuum gauge on it and see if I can narrow it down.

 

[Hedgehog]

Your vacuum lines might not be perfect, but they won't shut your engine down after running for a few minutes. Try turning your idol speed up a little.

 

[harleydragon]

before you idle it up,with the breather off,see if the choke is working properly and opening as it should. After the choke is opened put the vacuum gauge on and adjust the idle mixture screws at the least amount screwed out to get the maximum vacuum.adjust both idle mixture screws out the same amount.once the throttle plates open the idle mixture is taken out of the equation..

 

[furweln84]

Choke is working like it should, Ill try the vacuum gauge and mixture screws and post up. Thanks

 

[furweln84]

Your vacuum lines might not be perfect, but they won't shut your engine down after running for a few minutes. Try turning your idol speed up a little.

When I put my finger over the open pvc port in the back of the carb it killed the motor. It was also not even close to warmed up so it could have just been that. I think I do need to speed the idle up, cause it was running better when i gave it slightly more gas.

 

[Hedgehog]

I suppose I should, but I didn't consider PVC as part of the vasuum lines. That's a lot of air. Vacuum leaks make your engine run lean. If the motor requires air from the PVC system it sounds like your running very rich.

 

[furweln84]

Which could be a very likely possibility for an out of the box carb right? (forgive me its been 10+ years since Ive ran a carb.) So when I start to adjust the mixture screws should I still start with 1.5 turns out then go from there with the vacuum gauge/tune by sound?

 

[harleydragon]

Which could be a very likely possibility for an out of the box carb right? (forgive me its been 10+ years since Ive ran a carb.) So when I start to adjust the mixture screws should I still start with 1.5 turns out then go from there with the vacuum gauge/tune by sound?

you can start at 1 1/4 or 1 1/2 turns out..use the vacuum gauge and adjust them both in or out about a 1/4 turn at the time..find the point with the highest vacuum.then you might try it 1/8 of a turn either side of that to fine tune it..if the highest vacuum is found at say 1 1/2 turns out and then stays the same at 1 3/4 turns out then set it at the least amount out..you want the highest vacuum with the screws turned out the least amount to get that..that's just the way I was taught and it has always worked good for me..

 

[furweln84]

I suppose I should, but I didn't consider PVC as part of the vasuum lines. That's a lot of air. Vacuum leaks make your engine run lean. If the motor requires air from the PVC system it sounds like your running very rich.

Yep, it was running really rich, I leaned it out when I was attempting to tune it and it idles nicer without shutting off after a few minutes.

 

[furweln84]

you can start at 1 1/4 or 1 1/2 turns out..use the vacuum gauge and adjust them both in or out about a 1/4 turn at the time..find the point with the highest vacuum.then you might try it 1/8 of a turn either side of that to fine tune it..if the highest vacuum is found at say 1 1/2 turns out and then stays the same at 1 3/4 turns out then set it at the least amount out..you want the highest vacuum with the screws turned out the least amount to get that..that's just the way I was taught and it has always worked good for me..

Finally got around to putting the vacuum gauge on it and tuning, worked out nicely, thanks.