Jeep will not start

OK, I am losing my patience with this Jeep. The other morning I went out to go to work. Jeep would not start. So I read the no start thread on here and check everything. I took back my CPS and replaced it. I have spark. I have fuel. I even swapped plugs. Still wont fire. I then pulled plugs and shot a little starting fluid into each cylinder. Nothing. Nada. Zip. I am at my wits end with this. My hours are cut back right now, so I can not afford to keep throwing money at this thing. Anyone have any ideas what could make this not start? It is a 94 with a 2.5 4 cyl. Thanks.

Two things come to mind.

First with spark, you must have QUALITY spark. A strong, blue, snapping spark. Yellow/orange/white indicates a weak spark which may not be strong enough to start the engine (weak spark is often caused by a weak ignition coil)

If you have good spark (and only if), then you must verify actual fuel pressure. Your engine needs to reach a minimum fuel pressure for the engine to start. (check your manual for the spec). Then verify yours with a gauge; no shortcuts. Many parts stores will rent you a gauge inexpensively.

The fact that the engine won't even fire with starting fluid though, points to spark more than fuel.

Or it points to a flooded engine!!!! (if the spark is OK)

Hold the gas peddle to the floor and crank several times. If it starts, it was flooded!!! In which case we look for too little air (IAC valve stuck closed?), or too much fuel:

Check the vacuum line at the fuel pressure regulator for gasoline, if it is there, it is a bad FPR leaking and flooding the engine.

Also, in the fuel pressure test, do a leak down test (engine off after cranking), to see if an injector is leaking.

Lastly, check the dizzy rotor while pointing at plug #1 and pull plug #1 to see if the #1 piston is at TDC (to if the timing chain jumped or broke).

I will go to the Vato Zone and get a pressure tester and see if that fixes it. Now if it jumped time, would it have done that when I shut off the jeep?? Because it ran fine until I parked it, the next morning is when it would not start. And I do not have the manual, so I am assuming that #1 cyl is the one at the front of the motor, correct? I have not messed with too many 4 cylinders. And I am not sure I want to keep mesing with this one LOL. And if there is no fuel pressure, it would still at least ATTEMPT to start with starting fluid, right? And I know timing chain is not broke, I can see the rockers move when it is turning over (Removed oil cap to see if maybe timing chain broke. I was thinking that same thing.) And if it jumped time, then it would it even try to start? Fire at all?? Thanks again for everyones help.

Oh, and it is not flooded, I removed the plugs, let it sit overnight with no plugs in, then put new plugs in and it does the same thing. I will check and see where the piston and rotor are and see if that matches up. And I doubt it is the coil, I replaced it less than a month ago because I had a small miss. Which makes me ask another question: Could a timing chain cause a intermittent miss?? Always at low RPM, smoothed out at high RPM but still would sometimes even do it at high RPM. Thanks again!

Review my earlier post.

Don't overthink this.

First you need to see if you have, have not, or have poor quality spark. It's not that difficult. Remove a plug, keep it attached to the plug wire, place the plug electrode near a good engine ground, have a buddy crank the engine while you watch.

You must have QUALITY spark. A strong, blue, snapping spark. Yellow/orange/white indicates a weak spark which may not be strong enough to start the engine (weak spark is often caused by a weak ignition coil)

Spark is where I start for every single no-start vehicle I work on. You should to.

If he has the old coil that still worked, he could try it.

xCOYOTEx said:

Oh, and it is not flooded, I removed the plugs, let it sit overnight with no plugs in, then put new plugs in and it does the same thing. I will check and see where the piston and rotor are and see if that matches up. And I doubt it is the coil, I replaced it less than a month ago because I had a small miss. Which makes me ask another question: Could a timing chain cause a intermittent miss?? Always at low RPM, smoothed out at high RPM but still would sometimes even do it at high RPM. Thanks again!

Click to expand...

Drying out the plugs would NOT fix a flooding problem caused by a closed, stuck IAC. Try this anyway, takes all of 30 seconds to try it.

Hold the gas peddle to the floor and crank several times. If it starts, it was flooded!!! In which case we look for too little air (IAC valve stuck closed?), or too much fuel:

Click to expand...

Doing this, shuts off the fuel at the fuel injectors!!!!

Haynes says 1-2-3-4 timing front to back and 5 o'clock is the #1 spark on the cap on the dizzy.

OK, I believe the problem is a timing chain. With motor at TDC, the rotor is pointed in between # 1 cyl and # 3 cyl. So I am thinking it most likely jumped time. I have good spark, I even switched back to the old coil to test it and still nothing. I had tried the holding the pedal down trick before and it still did not start. And when I checked the plugs, they were wet the first time, but I took the old ones out, let it sit overnight with no plugs in, then put brand new plugs in. Still nothing. So i am going to take it apart this weekend and see what the chain looks like. Unless someone thinks I am overlooking something. And I have the notch on the balancer set at 0. Dead nuts on TDC. With that being said, would a timing chain jump like that just shutting it off??? I came home from work the one night, then the next morning is when it would not start. I have always changed out thiming chains before they broke, so this is new to me. Also, on a old V8 I normally would not change the crankshaft timing gear, just the cam gear and chain. Will this give me problems on the 2.5?? or should I be OK??

Out of my league now on those questions, maybe some of the engine hardware gurus will chime in now. Check the Dizzy and make sure it is not missing a tooth or two next!!! But I have always thought the gears needed to go too when replacing timing chains.

Well the bottom gear usually has little to no wer, but again, that is V8 GM, Ford etc. I guess I will just see what it looks like and go from there.

*wear

My 99 2.5L did this exact same thing to me today.

Ran great as normal last night. Got in this morning and it cranked right up as normal but when I put it in gear and let out the clutch it cut off. I tried to restart and it just turned over and over but no fire.

After checking all the fuses, wires, ect. I tried again. After about 3 mins of trying it fired up and idled. it ran for about couple minutes and I tried to give it gas it sputtered. I could gently give it gas and get the RPM's up but when I tried to rev it it cut off.

I put new plugs, wires, cap, and rotor in it about 10K ago. Today I put in a new coil, TPS, and CPS. I got it to fire up once more but it ran rough and ended up cutting off when I gave it throttle.

It also started backfiring through the intake, and kinda sputter when I turn the key back from running the starter.

When I try starting fluid I get nothing. I pulled the # 4 plug and can see sparks when the engine turns over. I tested the volts at the injectors and I can see the pulse and can hear the ticks. When I pressed on the valve on the fuel rail gas sprays out. I can hear the fuel pump cycle when the key is turned on.

Its getting spark ,fuel, and air but will not run....

I am left with wondering about jumped timing now I guess. I did replace the gears, chain, and tensioner about 10K ago when I replaced one of my pistons. I has been running great since I did all that until this morning (6 months later).

When I put the engine at TDC #1 and look at the rotor position, it does seem to be past the point where #1 should get a spark.

Did you figure out what caused yours to start acting up? Anyone else out there ever have the timing on one of these 2.5L engines just all of a sudden decide to go out?

I REALLY hate to pull it all apart just to find that it was something else :-(

Added ****
Also, I saw in another thread someone asked if the gauges were working, yes they all work as normal.

Just a thought - disconnect battery for a while reconnect and see what happens.

well...
I had it disconnected for about 5 mins during my testing but, I just went out and did it again and will leave it overnight and see what happens.

Map sensor is critical, and if the wiring or sensor, or vacuum connection is bad, that could cause the same running problem.

IAC could be stuck, or not getting a signal to reset causing the engine to flood or get too much air at start up. Fuel pressure or capacity flow may be too low. Spark may not be hot enough. Or cap or rotor may be bad (they can fail in odd, hard to see ways).

disconnecting made no difference.

I would think that if it was a problem with the MAP, or fuel pressure, or capacity it would still start when I used starting fluid.

How do I test how hot the spark is?

Ok, time for an update.

I did the whole process of setting the motor to TDC and opening up the distributer to see how things were lining up. All looked right according to the diagrams and directions on installing one. I went ahead and pulled out the Cam Position Sensor and cleaned it and the pulse ring (was a little dusty). Decided that there was no way the timing was knock out and put everything back together. Then I figured what the hell, and hit the starter. it sputter a few times and fired right up :-O

So the only thing I can think changed was cleaning out the Cam Position Sensor and replugging it back in.

I do have to say that it takes a quick acceleration a LOT better then it did. Before there was some occasional hesitation.

About to give it a good test drive to get data back into the computer, will post again later.

gray_penguin said:

disconnecting made no difference.

I would think that if it was a problem with the MAP, or fuel pressure, or capacity it would still start when I used starting fluid.

How do I test how hot the spark is?

Click to expand...

If it is getting too much gas, for whatever reason, or too little air (IAC problem), it will flood and starting fluid makes it worse.

You may have two problems!!!