brackenan

I went to start my 2001 Jeep Cherokee Sport 4x4 this afternoon and it won't start. It won't even fart. I know it's getting fuel b/c the fuel pump is fairly new and I can hear it pushing fuel. I checked all the fuses and they're all fine. I checked both fuse boxes too.

Funny, cuz it ran fine yesterday. Started right up with no problems. A neighbor of mine had a code reader, so he plugged it in and found 2 codes:

1. Missfire: Cylinder 2 (already knew that one)
2. And a large emissions leak. (I already knew that one too, and supposedly had that fixed a year or so ago when I got my emissions checked, even though it ran fine)

Any thoughts of ideas???

I feel so helpless and I have a new job that starts Monday and right now I have no running vehicle.

nickxj94

Check for spark? Check the cps?

brackenan

Ugh... Checking for spark would mean pulling off the coil pack... not fun. But if I have to I have to. And I just replaced the coils about 2 years ago...

Incidentally, what is "cps"?

brackenan

wait... is "cps" Crank Position Sensor? If so, someone just told me about it and I was wondering if that causes the vehicle to not start?

tjwalker

Both a bad crankshaft position sensor or a coil pack would prevent the vehicle from starting. And there certainly are other possibilities too.

But keep in mind that the crank sensor fails WAY more often. It really is a very common failure on the 4.0 engine. The crank sensor can be tested, but testing is not always conclusive. SEARCH for the procedure. If you end up buying one, do yourself a favor and buy a Mopar sensor from a Jeep dealer. Aftermarket crank sensors are "hit and miss" with a lot of miss.
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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 (wasted 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 wont damage the coil rail.
Because its difficult to guarantee that you can correctly ground all 6 plugs at once, you should make up 6 seperate 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 an 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.

rtralabama

Nss?

RTorrez1

OK, First off. When you turn the key does it turn over or it does nothing at all? If it does noting check your NSS. Try stating in nutral. If it turns over but no start Check you CPS.

brackenan

The engine turns over but doesn't start.

So the consensus is the CPS... I'm hearing that from multiple people and that's what seems to be the issue after doing some research on the Web. I will try and get one tonight and give a try at fixing it. It might be hard for me to get the time this weekend, so if not then I guess it's off to the shop.

RTorrez1

From what I have heard you want to get your new CPS from the dealer. Yes it's going to cost you more but it will be more reliable. I think that I was one of the lucky few that bought one off ebay. It has lasted me for over 2 years. But like I said that is rare for it last that long.