I have a 1989 jeep with 4.0. Did a complete tune up 6 months ago. Jeep has been running perfect. drove it this morning to work, about 2 miles. After work, wont start. It'll crank and crank but never fire. Checked and fuel pressure is fine at the rail so fuel pump seems to be working fine.

What do yall recommend to look at next?

 

No start:

three things to look at

Gas (pressure at the rail is good.........but what are the injectors doing?)

Fire

O2 (least common prob)

Is it getting fuel?

Is it getting fire through the plugs?

Is it getting enough air?

Most common is a fire issue. Is the coil wire connected? Is it grounded where "fire is going direct to ground"?

There are a myriad of possibilities here.

Fire test: Pull a plug wire off a plug. Put a screwdriver in the end. Lay "driver" next to a major metal part such as the valve cover. Allow about an 1/8" gap or so. Have a friend turn the engine over. Get spark? No...? It's in the ignition system. Yes..... More than likely in the fuel system. Now there are timing issues to consider as well. But this might help focus your direction.

Fire Okay? Sniff the tail pipe after cranking it awhile. Smell no gas? Then fuel problem. First blush: Fuel filter clogged.


Based on what you have said.......I would think ignition system. Coil pack, cap/rotor, coil wire. Just me, but that's where I would start considering what you have described.

 

Crank sensor, they tend to go without warning.

 

^^x2 cps will go out with no notice at all

 

well the update is that no spark. I pulled the wire an nothing, so I pulled the wire that leads from the coil to the distributor and no spark in it either.

So what is the next thing to check?

 

as previously stated check the crank position sensor