Sounds like you found the module.

Good - has gas, no run, ran great until then.

One more test, or you can "throw a likely part at it."

Get a new module - not expensive at all - around $20 I think. Once they get hot they can become intermittant - or quit completely. You should carry a spare anyway - so $$'s not wasted, especially since you have the TFI coil with the original module.

The test - next time it quits, quick test for spark, bet there is none.

 

How to test for spark when it quits?

What does the module do? anyone got a little summary for me? nice to know what I'm replacing

I will do the propane test tomorrow..
It's kind of hard to do when I'm all alone.. likely to blow myself up.

So I run it up.. get it to go to hell.. keep my foot on the gas so it doesn't start again.. (right?) and then crank on the propane?

If it fires and continues to run.. it's fuel.. if it doesn't it spark?

 

The module switches the coil on and off, creating the spark.

The propane - just drive it normally until it quits. As soon as you can - preferably while it's still coasting in gear, open the propane valve - it should be handy to the driver's seat. See if it runs, or even tries to run. If it does, it shows it ran out of gasoline = fuel problem.
You won't blow anything up as long as the hose is secuely in the air intake - don't point it at the distributor!

After you coast to a stop and it won't start, give it a squirt of propane again to see if it starts - again if it does it proves it wasn't getting gasoline. The propane will burn just about like gasoline.

If that test doesn't show anything or you take too long and it restarts on it's own, next step is test the ignition for spark when that's happening.

You'll need help for it. Drive it till it stops again, then quick jump out and pull the coil wire out of the coil about 1/2 inch. Have your friend try to start it while you watch to see if there's spark. Hold onto the wire, not the coil - if you have hold of the wire you won't get shocked if the ignition is working - just keep your fingers off the end.
Helps to loosen the wire before you drive it.
You should see a nice blue spark that can jump 3/4 to 1".

Or if you want to have some fun - have your friend pull the coil wire out of the center of the distributor and hold on to it - crank it - if he jumps around the ignitions working. Good way to get rid of a girlfriend you want to break up with too - she'll hate you forever.

But - you said you saw the carb give a good squirt of gas even when it wouldn't start. That affirms my suspicion that it's the module, not fuel.

The TFI coil has less primary resistance, that makes the module have to switch on and off about twice the current it's designed for. It's a real strain on the module. Since you didn't know where or what the module is, you probably didn't eliminate the ignition resister. So the module's the one under the stress, not the coil.
At best the Ford modules are unreliable, stretching things by using the TFI coil makes it even more so.
A new module quite likely will cure the problem - for now. But some day it'll probably happen again, so keep the module you have now as a spare. It may get you back to civilization if the new one dies.

 

Thanks again..

But.. the Jeep dies under load.. and coasts in gear.. pushing the engine..

IF.. I keep my foot on the gas.. the tires, push the dif, whcih pushes the tcase, tranny, and finally engine.. (like compression brakeing)
IF.. I put the clutch in.. tap the gas.. the engine gets back power.. and continuies to run..

So it doesn't actually all stop.. and I don't have to use the starter.. just get off the gas and then back on..

BUT.. I assume the propane trick will still work.. itll tell me fuel or no fuel.. right?)

so if I run on propane.. it's the fuel.. if it doesn't run on propane.. its the module/coil.
More then likely it's the module for the reasons you mentioned (right?) and I should replace the module/get a spare.

if that doesn't fix it then were talking coil??

 

"IF.. I put the clutch in.. tap the gas.. the engine gets back power.. and continuies to run..

So it doesn't actually all stop.. and I don't have to use the starter.. just get off the gas and then back on.."

Ah, new info again. That says fuel again. Based on that, forget the module for now.

Try the propane, it will verify for sure.
My guess now is as soon as you give it some propane it'll run again. If you give it just the right amount you should actually be able to drive it on the propane - the valve's the fuel, your foot's the air. It's hard to do, but it works.

 

Sweet.
Jeep'in on propane..

That mean I can run upside down now

ok.. so if this is the case.. and it is fuel..

where do I start? Or are you just the ignition guru and I have to find myself a fuel technitian

got a friend to help me tomorrow. should be interesting.

 

1. There are three ways of telling if you've got spark,
2. While the Jeep's toolin' down the highway... [*]Induction to a neon bulb [*]Long wired Timing Gun [*]Radio Frequency Interference on an AM radio.
3. The neon bulb must carry it's pulsed light,
4. Via a light tube to outside the hood...
5. The radio must be able to detect the RFI on the AM band.
6. Then you either [*]See, or [*]Hear
7. The pulse of the spark plug.

 

On any of the times it has acted up and you pulled over to check things, have you ever pulled off the air cleaner and looked down the carb?

 

Yes.. yesterday I looked down there.

everything LOOKS normal.. and fuel squirts when the throttle is pressed.

 

1. Do you still have a Cat Converter on that YJ?
2. If so, and the engine's "Bogging" down,
3. Then the backpressure may be building up.
4. Is it possible that the Cat's clogged?

 

Cat is gone

Someone mentioned the muffler could be jammed.

How do I check back pressure?
And now that I can hear an exhaust leak somewere (i think it's the joint between the manifold and down pipe didn't get tight enough)

so that would relive any back pressure wouldn't it?

Again, this is only under load.. I can rev it till it blows sitting still.

Gonna go do the propane thing right now.

If it blows up in my face I'm gonna be pissed.

 

1. Yep, the exhaust leak would releive back pressure.
2. So that comes back to the silly module,
3. In my way of thinking.
4. That ignition module looks somewhat like this:

 

Well I broke down and bought an electic pump.

I couldn't find anyone to help me with the propane. I mention propane and everyone around here wets themselves.
I get all the horror stories about how some guy did this or that.. it's probably all BS, and the guy was probably an idiot, but either way, my helper pissed off and wouldn't help.

So I bought the pump and was going to run, jerry can, pump, hose, carb. get everything else out of the loop.

THEN it started pissing wiht rain, and I got soaked hooking it all up. Pissed off, and now I"m inside warming up.

Tomorrow i go home. (on the bus.).. but that not cause of this, it's cause the ferry home is $10 for me, and $40 for me and my Jeep.

on monday.. I'll hook up the pump with a jerry can, and take it out for a spin.

If it works, then I know it's a pump/line issue.. and if not, then it's spark/carb issue.


Someone mentioned... that I should have a T after the filter that relives pressure and has aline back to the tank. I don't have one. could that be my problem?

Also, if it works in the jerry can, and electric pump.. should i bypass the mechanical one? or pump through it?

if I bypass it, I can just throw the pump on the frame right by the motor mount ( or back in the rear wheel well)

get rid of all the lines, and just run a softline from the rail straight to the filter then to the carb. and avoid the over/under the engine setup that I've got now.??

So now my big question. if I bypass the mech. pump.. do I just leave it be? or disable it? or what?

 

Why.. per-se.. would the exhaust leak bring me back to the module?

This problem started a LONG time ago.. and has gotten progressively (but slowly) worse...

but.. it also just started one fine day.. so it's not like I did something that made it happen..
Just out of the blue..

 

In reply to:

Why.. per-se.. would the exhaust leak bring me back to the module?

[/ QUOTE ]1. I only meant that the exhaust leak ruled out a clogged exhaust system,
2. That means, IMHO, that the problem is in the module,
3. Given the descriptions you've told us about.
4. The module, when it dies,
5. Usually goes a little at a time,
6. Not all at once,
7. It gives owners fits,
8. Trying to trace down the problem.
9. I can't urge you enough to change it...
10. It never hurts to have a spare...
11. And they're not that expensive,
12. Even in Canada!

 

Grr.

Well I don't have a problem getting to/from school

So I can wait until I get the electric pump hooked up. Gonna hook that up. and see if it's fuel or spark.

Thanks again for your help everyone.

I'm sure I'll be back with more problems on Monday.

 

So you are afraid of using a safe valve on a small propane bottle with a hunk of hose to the carb intake.
But you aren't afraid of driving around with an electric fuel pump sucking gas out of a gas can?

Great - But you are too late - I think the Polish invented that years ago - but you've improved on it - they called it a Molotov Cocktail - you have even provided an electric ignition device!

Make sure your heirs can post what happened on this board on this thread - or call a mechanic.

Using propane enrichment has been a diagnostic tool by professionals for many many years. Even factory service manuals refer to it. I've probably used it on more than 2000 cars without any mishap.
But in the hands of a --------.

Leve - I doubt it's the module - after interpreting what he was trying to say, he said it would quit, coast, but when he took it out of gear and feathered the throttle, it was still running, just no power. No need to restart. If the ignition had quit it would have been dead, right?
After a few moments of barely running, the carb would refill and it'd run again. So after that revelation, I went back to thinking fuel -- again!
Round and round we go.
The kicker was he said he did a volume test and it was fine.
I wonder how much fuel is in the oil now?

To everyone - for anybody to give help on the BB, we need ALL the information possible. And it has to be presented in a fashion that's understandable, not garbled, not held back. And the owner must be willing to do what is suggested.

I've learned from this - looking back at the original post I should have seen communication skills were lacking.

 

Sorry I'm not taking your word as lore...

But I'm not inclined to take information straight off here and apply it. Going to think for myself a bit before.

I was ready to do the propane thing, because I've played with propane before. I just didn't really want to do it on my own.
(Gas, Clutch, Brake, Propane, steering, shifter.) kind of alot to handle all alone.

I also feel I explained stuff rather clearly..

You have torealise that if it wasn't in the first post, it was because I hadn't figured it out.

I'm still learning about this problem.. as I'm tryingo find a solution.

 

Now a question about fuel pumps, filters, and carbs.

Whats the deal with the return line T...

Is it necessary? Can I run fuel into the filter, then out straight to the carb? If the pump puts out 3psi.. can the carb float valve hold that back? if it can.. then won't the pump just stop pushing fuel.. and backup? or do I need a resistor on a T, between the T and the line back to the tank, that lets fuel by at any pressure above what the carb NEEDS..

what pressure does the carb need? 3lbs? 4lbs?

 

If I were you I'd install the return line. It's there to keep a fresh, cool supply of gas running through. Without it, the gas in the line could vaporize and form bubbles that constrict the flow or build up in the pump and stop it from working.

This "vapor lock" problem is usually associated with hot summer months because that was the only time gas would get hot enough to vaporize. Now, though, the gas used in the winter is a much different blend. It will "boil" at temperatures as low as 70 degrees C (160F) because of a higher content of oxygenates like MTBE and ethanol.

Newer cars have their pumps in the tank and their fuel lines make a complete circuit back so vapor lock is almost never a problem anymore. With a mechanical pump and no return line, though, you're open for problems. I'm not saying it's THE problem you're having, but it's pretty easy to eliminate so why not.

The return line is probably still there, just cut off and capped or something. Throw on a dual-outlet filter like the CJ's use and you don't even need the "T". Keep the return output above the supply output when installed so vapor naturally goes in that direction.

 

Can I ask you one question here?

Does this engine have an EGR valve? When they go bad they tend to run fine until the engine gets warm ...and then cause problems much like you describe..

I didn't see anyone ask this ..nor did I see it mentioned.

 

The EGR is there.. but I doubt it works.

I don't have any vaccume lines or anything else.. previous owner "liberated" them all.

And I will put a return line on the fuel line..
along with putting the pump down by the tank on the frame rail.