Another "Not Starting thread"

[joe_peters]

Dang it--you are one pain in the toolbox!

Thought a little levity might help.

Would you believe I have just read this thread all over again?

Spark--present, rotor is turning when the engine cranks, right? You are getting spark distributed to each of the plugs in turn?

Fuel--quantity and quality. Disconnect the fuel line back at the tank and have someone turn the key ON, pump fuel into a clear glass container, about a quart, let it set for awhile and see if any water shows up in the bottom of the jar.

Air--You have got to be getting air, I know you pulled the intake off and sprayed ether into it.

Compression--you tested and showed one bad hole. Try this, take off the intake and have a friend hold the throttle open and crank the engine over with your palm over the throttle body. Disconnect the main coil wire from the distributor--the chance of a spit-back is probably ZERO, but I'm anal and don't want you hurt. You should feel the engine sucking your flesh into the throttle body--sounds worse than it feels. If you think it feels too weak, try it on a known running engine--again, disable the coil wire.

Fuel, air, compression, spark, each of them present at the right time, in the right quantity, and Houston we have ignition.

Take a break. Walk through each of the above, AGAIN, slowly and think it through. You are our eyes, ears, hands, and sense of smell.

Post back what you find.

 

[RLR_69_XJ]

Here is the link for the "spark" test. http://www.youtube.com/watch?v=ZTsJv1ukdB8
If you listen, you can hear the air blowing out the spark plug hole and its sparking at the same time. I did not test each plug, just the ones in the middle. I will do that just to make sure. I will test the "suction" but I am pretty sure its good, I can hear it when it cranks over.
The rotor is spinning, I watched it as I was moving the piston to the TDC point.
I had about half a tank when it died on me. When I changed the fuel filter, the fuel that came out looked good and clean. I will do as you are suggesting.

 

[joe_peters]

Checked your link.

Not the quickest cranking engine I have ever heard. However, you are meeting the Renix threshold of 300 RPM otherwise you wouldn't get the spark, your cranking voltage is greater than 9.0 volts so the electronics should be happy. Still, it does make me wonder what a better battery/larger cables/fresh starter would do--but don't go throwing parts at it, you know you have to rebuild the engine.

Ok, you are getting an impulse to each of the injectors. How about the fuel pressure? I don't remember seeing your numbers--should be 31 psi at the Schrader valve on the rail with the vacuum line attached, and 39 psi with the vacuum line disconnected.

And, are the injectors of a two-piece body design? If they are, those leak and the fuel you are smelling might just be the injectors leaking fuel. Look at this photo: http://www.jpmagazine.com/techarticles/engine/154_0811_preventing_jeep_engine_fires/photo_02.html

 

[RLR_69_XJ]

Ya, I had been cranking it for a while and did not have the charger on it. When its fresh or the charger is on it, it turns fast and sounds good... as far as trying to star goes.=/
I will try and pick up a fuel pressure gauge real soon and see if that part of the problem. I keep leaning more and more that way. To me it seems to be in the fuel delivery system.
Also, thanks for the help so far, I really appreciate it. And I know, I am a pain in the A$$, just ask my wife. =)

 

[RLR_69_XJ]

Ya, I had been cranking it for a while and did not have the charger on it. When its fresh or the charger is on it, it turns fast and sounds good... as far as trying to star goes.=/
I will try and pick up a fuel pressure gauge real soon and see if that part of the problem. I keep leaning more and more that way. To me it seems to be in the fuel delivery system.
Also, thanks for the help so far, I really appreciate it. And I know, I am a pain in the A$$, just ask my wife. =)

 

[kastein]

Really odd that it wouldn't start with ether into the intake when you suspect the fuel system. I'm just as puzzled though, got nothing, sorry...

Complete shot in the dark, but you said that the air whooshes out just as it sparks - does it spark at the end of the compression or partway through?

Really though, it does sound like a fuel delivery issue to me... not sure if it's injectors, or fuel pressure, or what, but that's what it seems like. You'd at least get a backfire or something if it was just firing ignition at the wrong point.

 

[winterbeater]

But like you say, if it was just missing fuel, the spray start should fire it up.

 

[bigalpha]

Could it be that the PO didn't use enough starter fluid; I know when I tried that method, I took it a little too easy the first go-around and it wouldn't do anything either.

My 88 MJ just had this same problem, it was running and then it died. Everything basically checked out good but when I let the fuel pump prime once or twice I had shit for pressure at the fuel rail. So bad that when I primed it with the fuel pump and hit the valve, air hissed out.

After troubleshooting my face off, I replaced the fuel filter and primed it with a generous amount of starting fluid. It then coughed, stumbled and started.

Possible to get some weird air bubble or cavitation in the fuel lines that prevents fuel from getting to the rail?

 

[RLR_69_XJ]

It’s my understanding that it should spark just before TDC for each cylinder. That’s why I was assuming the timing was correct because the piston was right at the top of the cylinder forcing the air out right about the same time it sparked.
I will look into the air idea too. I did change the fuel filter, so that might be an issue as well.
I know what you mean about the starter fluid, I would think it would at least give me a little stutter or something. Maybe I did not put enough in.

 

[bigalpha]

Try hitting it with some more starting fluid and see what happens. Don't put a ton in there, though.

 

[RLR_69_XJ]

So this is where I am at now. I drained some of the fuel and it has been sitting for more then a day now and looks good, I can’t see any water or derbies in it at all.
I got a fuel pressure gauge and tested the fuel pressure. I am getting about 34psi with the key on and about 38psi with the engine cranking.
The injectors look like the old design. I looked real close and can’t see any fuel around the injectors. It looks good and dry.
I tried MORE starter fluid in it today with no luck.
Could it maybe a timing chain or something like that? I would think that if that was the case I would have more compression issues but maybe the cylinder that reads 60psi is stuck open and the others are shut?
I’m not a mechanic so I am just spit ball’in here. If it had to do with printing t-shirts or embroidering hats then I would be all over it. =)