garyferg

still no start just acts like it wants to but no start guess maybe i should check fuel pressure although i smell gas hard job changing the cps but had trouble plugging it in wondering if the wire or plug is bad. suggestions? also with the coil pack how to you check spark? 2000 grand cheroke 4l thousand miles . when this all started to give trouble it ran but odometer would flicker corresponding to miss

Noah911

You could do this test;

(copied and pasted):

Step 1

Put on a pair of safety glasses to protect your eyes.

Step 2

Open the hood and loosen the bolt on the negative battery cable. Remove the negative battery cable from the negative battery terminal.

Step 3

Remove the coil pack mounting bolts with a wrench. There are four mounting bolts -- one in each corner of the coil pack. The coil pack is located on the left side of the engine, bolted onto the cylinder head. It connects directly to the engine spark plugs.

Step 4

Work the coil pack back and forth until you free it from the spark plug slots. Lift it up slightly and disconnect the electrical connector located on the back of the coil pack.

Step 5

Remove the coil pack from the engine and set it on a clean work surface.

Step 6

Activate the ohmmeter and set it on 20,000 ohms.

Step 7

Press both of the ohmmeter leads against the connections inside of each spark plug boot on the coil pack, one at a time (six total). Do not let the leads touch each other or else you will receive a faulty rating. The ohmmeter rating should fall between 6,000 and 30,000 ohms. If the ohmmeter rating is above or below this range, replace the coil pack.

Step 8

Change the ohmmeter setting to 10 ohms.

Step 9

Hold one lead in your left hand and one lead in your right hand. Press the left ohmmeter lead against the center prong inside the electrical connector on the back of the coil pack. Press the other lead against each of the spark plug boots, one at a time. The ohmmeter rating should be below 2 ohms. If the ohmmeter rating is above 2 ohms, replace the coil pack.

Follow the removal instructions in reverse the reinstall the coil pack.

Tip

• If even one of the coils on the coil pack is bad, you must replace the entire unit.

Noah911

Ignore this extra post here now

Noah911

And this;

(Copied and pasted):


The coil design for the 00-01 is significantly different than that of the single coil and distributor setup on the earlier 4.0. You basically have three coils firing 6 plugs in the correct sequence, every crankshaft rotation (waste spark design). This is an engineering departure from the older, single spark every other crankshaft rotation.

You can test the coil pack like you would the old single coil design, but its more technically involved than physically accessing the spark plug end. Because of the design of the coil rail, don’t test the coil rail one spark plug port at a time. Testing one port at a time causes the remaining coil ports to be free floating (ie, not properly grounded through the spark plug). Free floating an encapsulated coil secondary causes significant increases in the voltage induced in the secondary. This increased voltage can easily exceed the dielectric breakdown of the coil secondary and could cause the coil windings to arc internally and break down the insulation. If this happens, it has the effect of reducing coil energy delivery potential in the best cases and in the worst cases, causes the coil to fail. You need to install all 6 spark plugs to ensure you won’t damage the coil rail.

Because it is difficult to guarantee that you can correctly ground all 6 plugs at once, you should make up 6 separate jumper wires about 2 feet long. Pull the rail and flip it upside down. Insert 6 sparkplugs into the rail. Attach one end of a jumper wire to the threaded part of the sparkplug with a large mouth alligator clip and attach the other end of the jumper wire to engine ground.

Once all 6 are hooked up this way, you can then perform your engine cranking test while observing spark on all 6 plugs. You are looking for a strong, BLUE, snapping spark. Yellow/orange/white indicates a weak spark.

dave1123

00-01 is for the XJ. The WJ is 99-04. The coil pack LIKES to short internally. For instance, #1 and #6 fire together from coil #1 so there is a long connector running the full length of the pack to connect them. It just BEGS to short out! In the "waste spark" system, the plugs fire every revolution, on compression and on exhaust. Supposedly this was to reduce emissions.

People have replaced the coil pack with a set of LS coils or used the Viper setup. More reliable I would think.