abadrs

I have a 98 Cherokee sport 4.0 with 107k on it. I have been storing it for about 6-8 months due to I drive 30+ miles to work each way so to keep miles down I have been driving a beater. I have periodically started and drove it, with the last time being about month and a half ago. It ran perfect at this point. I went out the garage and started the engine. The jeep started right up ran 2-3 seconds and then shut off. After figuring out fuel pump was good (not only can I hear pump run with key I confirmed fuel at rail) I began trouble shooting and found I have no spark. I read lots of info that pointed to the CPS as the likely source. I replaced it with a OEM sensor and still nothing. I then went to seemingly the next likely culprit the switchplate/cam sensor/pick up coil whatever you prefer to call it. Nothing still no spark. I have confirmed distributor is spinning (in case of catastrophic failure) I also rotated motor by hand with key on and can hear relays kicking in and out under hood with both the new CPS and the old one. There is NO CODES. I confirmed with scan tool and self diagnostic (push mileage reset while turning key on). Jeep is never mudded and has no rust or corrosion anywhere. All the connections literally look like they did in 1998. I have spent nearly $150 already in parts and really dont want to keep throwing parts on that I cant take back. All I can find is Crank Sensor then sensor in distributor nothing after.
Im sorry for the long first post, but Im really perplexed.

jordan96xj

Check the 30amp ASD fuse in the PDC (the fusebox under the hood), then test the associate ASD relay for proper function. If these are seeing voltage at startup, but the sparkplugs are not, then I would move down to the condenser coil. If the fuse and relay are good, but they are not seeing voltage at startup, then the computer is stopping the ignition, which will probably take us back in the direction of CPS, cam sensor, or something else sensor related (or worst case computer related).

abadrs

I appreciate the quick reply. I checked the fuses and ADS relay they are fine that is what I heard clicking in and out when I rotate engine by hand. Check ignition coil next ?

Waynerd

First thing is check for power at the ignition coil. Start at spark plugs and work your way back.

Waynerd

Here's a good testing procedure.
http://www.fixjeeps.com/jeep-ignition-coil.html

abadrs

I actually broke the coil trying to get it unplugged from harness so I'll be adding one of those to my ever growing parts list, I metered the coil after breaking it and of course it was fine. But I have zero voltage at coil on primary side. Guy at dealership where I got crank sensor asked if key was chipped. I said I dont think so as I have a plain key and it works fine. Also I read where grey key heads are chipped and mine is black. All fuses under hood are good. What is the next thing in line to check ?

I do have a second "factory" key that Im planning on checking today to see if on the outside chance theres anything to the chip thing

abadrs

While Im buying this coil anyway is there a decent one sold at any of the auto parts stores ? Or are they mostly junk ? This jeep is really nice and I want to use decent parts on it (after it runs again)

jordan96xj

That's a complicated question, but the real challenge is that a place like Advance will be able to get 3-4 different variants, but may only have one of them on the shelf. So you end up having to be patient and avoid the crap.

At NAPA they will probably carry 2 different coils, one slightly more expensive than the other. They will probably have the cheaper one on the shelf, but be able to get the better one quickly (same day sometimes). Whenever NAPA offers the two options, always take the higher one (this is a whole discussion in itself, but for now, take the higher one).

abadrs

Yea not to get off topic with the coil.. Like I said just looking for something that meters close to stock. I found an accel suoer coil on amazon for 47 dollars. likely Ill just get that seeing how the autozone one was more than that.

So any ideas on the lacking of 12v at the coil ?

jordan96xj

You said the connections look good like they are from 1998, but have you actually taken the time to clean and reconnect your battery clamps, and ground connections? Just because they look good doesn't mean anything. That is where I would start. Because it is simple, free, and needs to be ruled out first.

abadrs

Yep checked and cleaned.

I need to know where the 12v comes from that feeds the coil when key is on.

jordan96xj

It (+) comes from the PDC. It goes through the ASD relay, then ASD fuse then to the ignition coil. The ground (-) side of the ignition coil comes from the PCM (ignition coil driver).

jordan96xj

Removed: was a picture of my 96 pdc, but got confused with another post. The 96 pdc, won't be a close match for the 98.

abadrs

After doing some more searching I've found that my coil should not have a constant 12 v on coil. It should have 12 v after key is turned on for a second which it does and while cranking which it also does for a full five seconds. Hoping to get new coil on ... Old coil has good primary resistance but secondary shows open so hopefully thats what it is.. If anyone else has any other ideas Id love to hear them

RayaRg1

Have no constant 12 volts to ignition coil why?