Motor won't start

which engine?
2001 WJ , jeep.
wrong spark plugs!
gapped wrong!
wrong wire order?
do tell engine you have there.
do tell park plug brand and numbers.
do tell if engine has coil packs, how many, and how you wired them back..
now answering for USA cars, (not exports. or those jeeps made in Europe. )

the 4.0L engine with the 3 coil rack pack? with 6 spark wire sets?
the 4.7liter has 6 coil packs coil over plug COPS.
that can not be wired wrong but could be unplugged in primary side.

my guess, wrong parts, wrong gap
or not reconnected right.
if spark is lost, scan the PCM cranking, look for DTCs/

check all fuses first, every time, something fails EFI.
the scan tool will tell you why 90 % of time.
connect scan tool
key on
crank for 5 seconds, see scan tool show 300 RPM? about.
good, no RPM is bad sensor (Cmp or ckp)
release key , do not turn off yet
see DTCs stored, now, bingo, its telling you what is bad. OMG.
p0340/ 355? and the like? are bad CMP, bad CKP, or others get em
post em or look them up in the FSM. or at alldata.com
Theory:
the ECU creates spark
there are the 2 sensors that tell the ECU when to spark (inputs)
and the ECU DRIVER the ignition IGNOTOR, that runs the ignition coil.
1 coil or 6 coils. depends on year.
4.0L I6 Jeep engines.


did you check for spark directly at the 1 coil car or at all 6 coils for 6 cop coil cars?

cops are coil over park plug, i think your car is 1 coil, had a 99 jeep.
and this old six still had one, coil, so does this one coil make spark
to a test spark plug, Y/N
if yes, the dizzy cap is bad or wired wrong. to plugs.
I no spark here, do the DTC scans above.!!!!!
post back results.

pick up coil or module ?

Remove distributor cap have someone tap the key while you watch the rotor inside the distributor if it does not move that is the problem then it could be the gear shear pin has broke or cam is not turning distributor.

what motor? is the coil producing spark?? If so, check the fuel pressure, if the fuel pressure is low drop the tank, repace the pump and also replace the filter (located on the frame forward of the tank). If the coil is not producing spark, check for shorts or opens in the circuits as well as the IGN fuses. If there is NO fuel pressure at all check the fuel pump fuses and make sure the fuel pump is plugged in and there are no opens in the circuit

Yellow means weak spark should be blue check the coil tower where the coil wire attaches on the coil for corrosion. Also check the spark plugs for wear.

I take it that it cranks over but will not start. Spray some starter fluid into the throttle body. If it runs, you have a fuel problem. You may have disconnected the fuel system by unplugging a connector or grounding a wire blowing a fuse.

Check the timing to ensure it is correct.
Check each cylinder for the proper compression.
Try starting the jeep with some starting fluid. If it starts with the starting fluid, you may have a few bad injectors, or faulty injector wiring harness.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

check your coil, plugs, wires, basically your entire ignition system - test a plug wire by sticking a new (known to spark) sparkplug onto the end of the (known to work) wire and see if there is spark, if not, change out your coil and test again - if neither, check the timing of your distributor

Here are a couple of things that could be causing your problem. 1. Bad ignition coil or ignition module 2. Clogged fuel filter 3. Clogged air filter 4. Clogged fuel injectors 5. Bad spark plugs, wires, distributor cap and /or rotor. 6. Broken timing chain/belt. Here are a few things you can try to verify that you have a good spark. 1. Remove the distributor cap and crank the car. If the rotor turned you're ok. If it doesn't turn then that's you're problem and you will probably need to change a timing belt/chain. 2. Check the spark from the ignition coil by pulling the coil wire from the center of the distributor. Use an alligator clip to attach a short wire to the coil wire contact. Bare the other end of this short wire and set it up so it's sitting very close to the engine block. Turn off the lights and try to start the car. You should see a spark jump from this wire to the block. If you don't see a spark it's likely your ignition module or ignition coil is bad. 3. If you have a spark maybe it's not getting to the plugs. You may need to replace the distributor cap and rotor. You can test if the plugs are sparking by pulling one, re-attaching the spark plug wire and seeing if you get a spark when you try to start the engine in the dark. Please note, the metal threads of the spark plug need to be shorted to the engine block to complete the circuit during this test.