Davedough

I dont post much, but browse often. I've searched tirelessly throughout this forum and have followed several threads trying to fix my Jeep and I've run into a brick wall. Here's the situation.

I have a 1993 XJ Sport 4x4 with the 4.0L. It has been sitting for about 4 months since I only ever used it to pull my boat and this past Friday, I went out to start it. It started confidently like it always does and I was letting it idle while cleaning out the interior. It idled for all of about 2 minutes and then quit, dead. I tried to turn it over and got nothing.

Over the course of this weekend, I've been working on it. At first, I checked for spark and was getting weak spark from the coil and no spark to the plugs. I change the coil, no deal, changed the plugs/wires, nothing, I bought a new distributor since the cam sensor is almost the same price of a new dist, and that didn't work. I was still getting really weak spark. After that, I went underneath, grabbed my fancy tools that you swear you're never going to use and managed to wrestle off the crankshaft sensor on the bellhousing of the tranny. I put a new one of those one, and now I have great spark all the way to the cylinders, but the damn thing still wont fire.

When I replaced the dist, I scored the block and dist for the positions, marked where the rotor was pointing and copied those score marks directly over to the new dist. When I put the new one in, I was one tooth off, so I had to take it back out and repositioned it correctly. I dont think any of that would have knocked it out of time.

I'm at my wits end with this thing. I've dumped over $200 in a Jeep I'm actually trying to sell now and I'm not sure what else can be wrong. Suggestions?

Birdcr125

You could try checking to make sure you got good fuel pressure ay the fuel rail maybe a bad fuel pump or a clogged line or filter

fishtaconc

You a have confirmed spark, spray some starting fluid, or a little gas in the throttle body, see if if fires up and runs for a bit. If it does, then you have fuel delivery problem, Verify the fuel pump comes on when you turn the key on, it should run for about 2-3 seconds, if it does then check fuel pressure at the fuel rail with a gauge, these are available for rent at the big box parts stores. Should have 31 PSI at the rail.

If the fuel pump does not come on, swap the fuel pump relay with a known working relay in the under hood relay box. I believe the 93s still had the ballast resistor(ceramic thing on the DS fender well), you can bypass it by jumpering the wires together.

Davedough

Thanks guys. I'll try those tomorrow morning and let you know.

Davedough

Ok, well. I put a Multimeter to my fuel pump relay and I get 76.3 ohms across the coil which from what I read is as long as you're under 200, you're good. So I think the fuel pump relay is ok. I also tried swapping it with the Alt Fan relay right next to it and still no start.

The fuel pump kicks on and runs for about 2 seconds. I put a pressure gauge up to the pet **** on the top of the fuel rail and I get a steady 31 PSI at the rail with the key on. Also, from what I've read, that's exactly where it should be.

And just because I'm a tech geek, I took a picture of it.



I haven't tried throwing any starting fluid or fuel into the intake yet, but if I'm getting that kind of delivery at the rail, I should be ok with delivery right?

Davedough

Anybody?

I'm still having problems with this. As I stated, I've got good fuel pressure at the rail, new dist, new crankshaft positioning sensor, new plugs, new wires, new coil, new cap, new rotor. I've confirmed I'm TDC on the #1 compression stroke with the rotor pointing to #1 post. It just cranks and cranks and will not fire. I've gotten a couple of very small burps through the ignition and nothing else. I put some gasoline in the intake and it still did not fire.

I'm about to shove it off a cliff. Please if anyone has any ideas it would be very helpful.

F1Addict

There are only two things required for a running engine (assuming no broken internals)... Spark and fuel. If your plugs are snapping away then it's got to be fuel. If you've checked pressure to the rail then it's got to be upflow from there and the only thing left are your injectors.

stev-o

xx2
And u have spark and fuel a good spark

beijingjeep

Make sure you are getting spark at the plugs... pull one and ground it and see what you got. Either you are not getting spark or your injectors are dead... possibly a fuse to these?

stev-o

Did u ever get it started

tjwalker

You state you have good BLUE spark now?

If that is the case, you really must try a splash of gas or starting fluid into the intake. Take the fuel pump circuit out of the equation for this piece of troubleshooting. If it runs for a short time, you have confirmed a fuel delivery problem.

And the other thing I haven't seen confirmation of is firing of the fuel injectors. I use a simple "noid light" for this. Mounts inline and confirms that your fuel injectors are getting direction to fire.

All the spark and fuel in the world isn't going to help you if the computer isn't sending a pulse to your fuel injectors.