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TMSquy 10-28-2013 05:27 PM

1989 yj 2.5 engine wont start or run
The jeep sat for awhile and I have worked around it for awhile. Here and there I tried diagnosing the problem. The injectors spraying fuel and it has spark. Timing chain was replaced recently and cylinder 1 at tdc has both valves shut. Distributor was recently replaced. The problem I'm having is fuel mixture isn't entering the combustion chamber. I tried pouring large quantities of gasoline into the intake manifold, crank it a few times, still no fuel to plugs. Anyone has any experience why? I tried replacing the egr valve and made no differrence. I unbolted to downpipe thinking a clogged exhaust isn't allowing flow, still no mixture to combustion chamber.

Que89YJ 10-28-2013 05:31 PM

The only way fuel can't get to the plugs if you are pouring fuel into the throttle body with the butterfly open is if something is blocking the throttle body.

TMSquy 10-28-2013 05:44 PM

Even if butterfly is open it doesn't help.

Que89YJ 10-28-2013 07:19 PM

How are you telling it fuel is getting to the cylinder?

TMSquy 10-28-2013 08:42 PM

Mixture isnt getting to the combustion chamber. Plugs bone dry. Spray either in the plug holes it attempts to fire.

Que89YJ 10-28-2013 09:14 PM

Then you need to pull the manifold and see where it's blocked. Something has nested in there while it was setting for such a long time. There it's no other reason for something from the throttle body not to get into the cylinder through the intake.

TMSquy 10-28-2013 11:55 PM

That's only option. Otherwise I would say the valves aren't seating

Que89YJ 10-29-2013 06:53 AM

The valves not opening.

TMSquy 10-30-2013 12:00 AM

I wonder why. I might pull the valve cover and see if I can find anything going on with the valvetrain

Que89YJ 10-30-2013 08:09 AM

Yes, if the valves are working then you need to pull the intake. Chances are that something set up house in the intake while it was setting.....maybe the exhaust too. Could be blocked stopping you from pushing any air.

Siva283 10-30-2013 01:41 PM

Wouldnt a compression test be a good idea? With the exception of bone dry spark plugs this sounds very similar to the issue I was having. If exhaust or intake is blocked wouldnt that mess up compression as well. Definitly easier than pulling the manifolds.

Que89YJ 10-30-2013 02:34 PM

Compression test and a bleed down test. I don't know how anything can get past the throttle plate. The more I think about it. Run the compression test. The bleed down kit should come with it. I would be real curious if something nested in the exhaust and its totally plugged. With the bleed down test it comes with a connector to put air in the cylinder. I would crack up the air pressure and see what comes out of the exhaust. Or have someone turn it over and stand at the tailpipe and see how much air is being pushed out.

TMSquy 11-03-2013 01:03 AM

Like I said, I unbolted the downpipe to see if something blocked the exhaust. Its on open manifold at the moment. Compression reads roughly 115 each cylinder. Tommorrow ill unholy the valve cover and see if the rockers are pushing the valves properly. That and or if something happened to the pushrods. The compression is a bit low, but not low enough to say it shouldn't run.

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