OK so after reading numerous posts, I have (1)replaced distributor cap,(2) all spark plugs (3) new rotor (4) crankshaft position sensor. Which was just loads of fun, and I still have no start. I have spark, and fuel. It is a 94 cherokee sport, 6cyl 4.0. Any help would be great, at my wits end, it ran fine, then one day just wouldn't start. D I D ( dead in driveway) THANKS Ohhh I miss my Jeep

Welcome to AF tpb70


So you need three things to have the engine run.

1. spark at the right time
2. fuel at the right time (with FI) and the right amount.
3. compression

So where are you lacking???

Do you have any computer codes showing up???

What more can you tell us??

JD

Don't know what else to tell you? Lets see, I bought it for 700 bucks, it has 194k on it. Decided one day to do some preventative maintenence, changed the plugs. After that it started running really rough, regaped plugs no solution.

I checked all plug wires for continuity, all ok. I checked distributor cap and rotor, which were corroded so, I replaced. Ran fine for about two weeks, then went to start it, and no start. Suspected old battery, changed battery. No start, checked CPS with voltmeter, read as dead.

Changed CPS still no start. Checked fuel pump, sprays fuel well. Checked spark, great spark.

Don;t know what else to do, I do not know how to do a compression check.

As far as codes, it does not read any codes, whereas I did the ignition on off cycle.

700 bucks and 194K..... If this were my Jeep I would replace everything related to iginiton, fuel and emissions; I would assume (bad word, I know) that all the major components are original and, at 194K, are well past their expected lifespans or on death's doorstep.

Fuel system: replace the fuel pump; replace the fuel filter; (since the XJ is D.I.D.) remove and clean the injectors (otherwise drive it to a good shop and have an upper intake track cleaning done). I would do this one at a time so the injectors go back from where they were pulled. Correct fuel pressure needs to be confirmed at the fuel rail (that feeds all the injectors. Remove the throttle body and scour it clean with intake track cleaner (this is not carb cleaner....it's much stronger and designed to remove carbon deposits). If there is an IAC (idle air control) remove it, clean the passage and install a new IAC..... you want all this stuff to sparkle. Reinstall TB with a new gasket.

Ignition: plugs, wires, cap and rotor.

Emissions: Got an EGR valve? Replace it. Thoroughly clean the crankcase vent system to include the hoses (or replace them). Catalytic converters get plugged over time.... put a new one in.

Compression check: Normally done at operating tempurature but you can get some idea with a cold engine.... Remove all the plugs, pull and ground the high tension lead from the coil. Install the compression tester (it usually screws into the spark plug hole); hold fully open the throttle plate. A remote starter switch makes the job a wee bit easier but barring that, crank the engine with the key. How much? Five or six pops on the cylinder being tested (you'll hear the difference when the tested cylinder runs through TDC).... just make sure you are consistent in the number of cycles. Lowest reading shouldn't any less than 75% of the highest reading..... not sure what the cranking PSI spec is.... this will give you an idea how "tired" the engine is. You can have fairly equal readings between each cylinder but they may all be equally low.... which means your motor is aging properly.


Good luck....

mike

Cehck the fuel pressure at the rail, had an 89 do the same thing, turned out to be both the fuel pressure regulator and the fuel pump check valve (had to replace it) along with a leaking injector.

try putting an oz. of gas down the throttle body, also hold the gas pedal down a little while trying to start. How did you determine it was getting gas?

how do you know it sprays fuel well?

OK so after reading numerous posts, I have (1)replaced distributor cap,(2) all spark plugs (3) new rotor (4) crankshaft position sensor. Which was just loads of fun, and I still have no start. I have spark, and fuel. It is a 94 cherokee sport, 6cyl 4.0. Any help would be great, at my wits end, it ran fine, then one day just wouldn't start. D I D ( dead in driveway) THANKS Ohhh I miss my Jeep

I'm dead in the driveway also. Died the day I was to start a new job and move. ordered the CPS, will see if that works, already replaced a cracked coil.
I've got no spark at all, I'm a GM man, if it was GM, i'd have hot wired the coil already.

but these mopar confuse me.

computer codes say it's the CPS, we will see.

I'm dead in the driveway also. Died the day I was to start a new job and move. ordered the CPS, will see if that works, already replaced a cracked coil.
I've got no spark at all, I'm a GM man, if it was GM, i'd have hot wired the coil already.

but these mopar confuse me.

computer codes say it's the CPS, we will see.

Well, let me tell you, the CPS is a real fun job. The easiest way I can tell you is to lay sideways under the drivers' side. Then, you will need a long extension, swivel adapter and I am pretty sure it is 17mm socket-could be wrong on the size however after much frustration, it def is mm.

Good luck with that!

Well, let me tell you, the CPS is a real fun job. The easiest way I can tell you is to lay sideways under the drivers' side. Then, you will need a long extension, swivel adapter and I am pretty sure it is 17mm socket-could be wrong on the size however after much frustration, it def is mm.

Good luck with that!

have had it out 3 times already, bought the extension and swivel right off the bat, it's an 11 mil. socket

i sure hope this is what's wrong, I'm stumped and i have to move.

picking up the part in 30 minutes.

will let you know.