Stalling 258

[jay79cj7]

79 258 with auto trans. It ran fine about 2 weeks ago. Now its sputtering and dying on me. Sometimes it starts up fine and dies right after the starter disengages. Sometimes it starts and idles a little rough and dies when I put it in gear. Sometimes it seems to idle fine, and drives OK, but then when I mash the skinny pedal too hard it sputters and dies. Sometimes when it dies it sounds like its blowing air out the intake. It did not used to do this.

I can't find a vacuum leak anywhere. I took carb cleaner and sprayed it around the base of the carb and the intake manifold and it didn't rev the engine at all. I have not changed the adjustments on the carb at all, except to raise the idle a bit because of this problem. (It seems to idle lower now too.)

Any advice on what this could be? I finally have my CJ back together and summer is here, and I don't trust it to take me anywhere!

 

[jay79cj7]

RE: Re: RE: vinal top cleaners

Little help?
Still having the same problem. I re-torqued the manifold and carb, but I don't think I had a leak there anyway.
Its idling low in drive and stalling sometimes. Major hesitation/stall when I hit the gas too hard. Like somebody shot the horse!

 

[GaryMB]

I've been having the exact same symptoms with my cj. Turns out the choke was not working properly, creating a rich condition with little air where it would die no matter how slowly i let out the clutch, especially when cold, and would not accelerate when I gave it gas, and sometimes backfire out of the carb (I had a 3 foot flame one time with the air cleaner off). Ocassionaly it would run OK. If the choke is not the problem, then I would check the fuel delivery system and carb adjustments (incase it is running too rich), and the ignition system.

 

[jay79cj7]

AGR or rebuilt stock steering box?

Thanks for the ideas. The choke seems to be fine, its opening up as the engine warms up. (I assume yours was staying closed?)
I let it idle for a while to make sure it was at operating temp and took it out for a drive. It died at a stoplight when I went to hit the gas, then again in a similar situation. Some jerk was nice enough to honk at me repeatedly. The idle has always dropped down 200 or so when I go from park or neutral to gear since I got it, so I assume thats normal. It still does it, but it starts out at a lower idle, so it ends up idle in drive around 500-700. It doesn't like hitting that 500 mark. That's why I upped the idle speed, but it really didn't seem to make much of a difference. That screw is almost all the way in.
I cleaned out the venturis and that didn't help.
I put in a new fuel filter and checked all the lines. They seem to be fine.
I have never messed with the mixture screws on the carb, only the idle speed. I doubt that would have changed on its own, but who knows. I don't want to start messing with the carb adjustments because I don't think that's it and I really don't want to create more problems.
Similarly, I have never adjusted the timing. Could this need adjustment for some reason?
The ignition system is TFI with a ballast resistor. Its a new painless wiring harness, but it ran fine after I put it in, so I don't think I wired it wrong. The ignition module and coil are new. The plugs are relatively new and look fine.

Could the coil voltage be to blame? That is one area that I know isn't quite right. The painless kit has a ballast resistor instead of a ballast wire like stock. I am using this with the TFI coil. It ran fine for a couple weeks (very short trips only.) Then one day the thing wouldn't start and it turned out both the coil and module were bad. I don't know how that happened. During the process of figuring that out, I also left the ignition on and burned up the ballast resistor. Oops. So now I am using a different ballast resistor that someone recommended to me about a year ago that I picked up. The coil has about 7V on it right now. Is that too low? I think the painless one was a little higher, around 9, but the module burned out with that...

Please somebody give me the magic answer. I want to drive this thing. My family and friends are all giving me crap too! My fiance said she knows whats wrong with it: I took it apart! Please help me show her up.

 

[GaryMB]

RE: AGR or rebuilt stock steering box?

Do you have emissions testing where you live? If not, I would just put in an hei distributor to simplify things a whole lot. No need to worry about voltage with an hei. And it's reliable. The timing should not be off unless the distributor hold down bolt is loose, or the timing was never readjusted after the tfi swap. Also faulty smog stuff can screw things up too. Have you tested the fuel pressure? could be a bad pump. I would also check the spark plugs for any fouling.

 

[jay79cj7]

electric fan

I don't have a means of testing fuel pressure, but the pump only has about 7-8k miles (2-3 years) on it, so I would hope that it's still good.
And yes, I do have emissions testing. Nothing too tough, just a sniffer at idle, no underhood inspection or anything. That's one reason that I have never messed with the timing or carb mixture... I am sure it could be optimized, but it has worked and got by the law.
I could do the HEI, if it would pass emissions, but I just spent a crapload of money on this thing. Plus, it used to run great and I want to get to the root of the problem.
The plugs looked good when I took them out this evening. Gapped correctly and all.
Thanks again!

 

[GaryMB]

RE: electric fan

I believe that the 1979 cj's don't have computers, and therefor installing an hei will not hurt emissions. If the module and coil got fried simultaneously, then I bet the problem is electrical. 7v is lower than stock, but then again some other vehicles do use 7v stock. I would just install an hei. I know exactly how you feel about the tfi...I put several hundred dollars and many hours into making my jeep smogable--new carter carb, tfi, all new everything...I just gave up and did a motorcraft and hei after the computer got fried--it was just one thing after another. I bet the jeep would pass emissions with a motorcraft if you tweaked it to run lean right before testing, but that's another issue. Maybe you could sell the tfi as a kit on ebay to finance the hei? Keeping it simple is my vote...

 

[jay79cj7]

You are correct sir, 79s do not have computers, so I guess that makes sense on emissions. I hear you on the keeping it simple, and maybe I will go that route, but I would like to get to the root cause of the problem rather than just start replacing systems like that. (That may just be the engineer in me talking...) Maybe that would be the easiest route though.
What is the stock voltage at the coil? 9v?
By the way, when I was driving it, I took it up to 50 mph, so engine speed was not a problem... It was getting enough fuel, etc. It was the sharp change in the gas pedal that it did not like... Something carb-related?

 

[GaryMB]

New addition to the family...

The stock voltage at the coil is 9v constant. To find the root of the problem your best bet might just be to dive into it with a multimeter. Whenever my jeep has backfired out of the carb it has been attributed to it running too rich, though i believe that the timing being way off can cause that too. Perhaps punching the gas is flooding the engine? I would suggest checking out the fuel/air mixture ratio with the help of a vacuum gauge, but the fact that it just suddenly started dying and sputtering makes me think some componet failed rather than falling out of adjustment.

 

[jay79cj7]

RE: well then...

Yes, I agree, it seems like component failure rather than adjustment. Thanks for the help.

 

[jay79cj7]

I GOT IT!!! I don't know why, but it was the ballast resistor!

A year or two ago I decided to replace some damaged wires under the hood. I replaced the ballast wire because I didn't know better. Then I burned out my TFI coil and somebody on Jeepz explained my error. He recommended that I use the ballast resistor from an old Dodge or some radio shack resistors. I tried both. Radio Shack worked great, but the Dodge one gave me trouble. I don't think it would even start. At the time I attributed it to not having a ballast bypass wired in for start. I ran with the RS for the past year or two without issue.

As I mentioned earlier, I had blown a TFI coil and ignition module very shortly after putting in the painless kit with their supplied ballast resistor. I also burned up the resistor.

I had been using the old Dodge resistor after the painless one burned out because I needed a resistor, found it laying around and it seemed to work. It started at least. Now I have a ballast bypass, which I guess explains the starting and then dying at times. The voltage was around 7-7.5v at the coil when running, and it ran, but gave me problems (obviously).

I got a replacement from painless and tried it out. It put 11V or more at the coil... No wonder the TFI and module burned out. It was running, but I didn't want to leave it on too long and blow another $40 in parts.

I pulled out the old RS resistors and tried them. It worked like a charm. The voltage is also right around 7-7.5v, just like the Dodge, but for some reason it just works. It doesn't die, I can floor it without dying, etc. All symptoms gone. I put the Dodge one back in and it went back to running like crap.

I can't explain it, but I beat it! Maybe there is some sort of inductance with the Dodge resistor that screws up the way the module alters the timing. Who knows. Theories are welcome because I am curious.

Now, the reason I never liked the RS resistors is they just don't look tough enough to handle being under the hood for very long. I really feel like I need to have an automotive part under there. Does anybody have any suggestions on a ballast resistor that will give me 7-9V at the coil?

Thanks for the help GaryMB!

 

[Junkpile]

The Accel coils come with ballast resistors that are 9v......or at least I'm pretty sure they are. Anyway, you should be able to buy just the resistor at any autoparts store that sells that brand coil.

That's what I always run. I accidently wired past the resistor on my CJ when I first put this engine in. The plastic casing on the Accel Super Coil blew apart!