wingnut37

At a loss, so in 2012, you take to the interwebs. Drove home from work, parked, and wouldn't run the next day. I've got no spark from the ignition coil. Replaced that. No change. Googled things. Ahha, CPS must be it. Replaced that. No change. (btw, since it's such a pain to get to, I just cut a hole in the floorboard of the jeep. Can get it in and out in about 3 minutes now...). So, I'm teetering on the edge of my technical abilities trying to figure out how to resolve. She cranks and cranks, but won't fire. Other threads kind of point to ECU/ICU/ECM/ICM. I guess I can keep throwing parts at it, but frankly, I'm ready to roll it into the street and light it on fire. Anyone with a magic bullet solution here? Many thanks for in advance for the help.

rompnXJ

check your fuses; mainly the ignition fuses underhood. if those check out ok, check the sync sensor & rotor inside the distributor cap.

tjwalker

Spark: 12 volts from ignition switch to the ASD relay; when the key is first turned on the PCM provides a ground to the ASD relay to energize it, then the ASD relay passes 12 volts to the coil primary side. If no crank sensor signal is generated after a couple of seconds the PCM cuts the ground to the ASD relay (and fuel pump relay too) and that cuts power to the coil (and fuel pump). Key to START and once again the PCM energizes the ASD relay. Now, a critical element is the crank sensor--no signal from the crank sensor and the PCM won't trigger the coil to provide spark.

Radi

Try swapping the ASD relay with another.

RTorrez1

The CPS that you put in Where did you purchase it? I know that anything other then OEM are hit and miss.

freegdr

Have ya removed the dist cap and looked in there my 94 hall effect sensor had rotted out ?

wingnut37

Forgive me for not getting to the Jeep tonight, mother in law's PT Cruiser had its own set of problems today. I'll get into the Jeep tomorrow and re-check fuses, swap ASD relay and check rotor/sync sensor. For what it's worth, the CPS was made by BWD I believe -- Advance Auto Parts. Will pass on results afterward.

Btw, how else did ANYONE have hands small enough to change CPS without cutting a hole in the floorboard?? (Or dropping the tranny!). Truly an impossible location. SMH.

rompnXJ

unbolt the front driveshaft from the diff yoke and disconnect the transmission shift cable from the trans and it opens up tons of room. only takes a couple minutes. when somethins in ur way, it gots to git.

btw seal that hole up with somethin, cherokee floorboards dont need any extra excuses to rust themselves.. my last jeep had a couple penny sized holes in the rear floorboard when i got it and a year later i had stopsigns for rear floors lol

wingnut37

Update: followed suggestions -- fuses are all good, swapped ASD relay with known good one, rotor and cap are fine. Already replaced CPS. RompnXJ had suggested a sync sensor (same thing as a Cam Position Sensor?) -- I'm assuming this is integrated in the distributor housing? Operating on that assumption, I replaced the distributor. No change. Still won't fire. Anything else I could be overlooking??

Radi

Do you have battery voltage at the positive coil terminal? And about half that (or so) at the negative terminal while cranking the engine?

rockswealth

I have been doing the same thing with my 96 Jeep Cherokee. Sunday we put in a new ignition switch, because when one guy put in the new ignition key and lock he didn't follow the directions. Hoping that was the problem no such look. We are still not getting a spark and have replaced everything related to ignition. If someone helps you maybe they will be able to help me also. Best of luck and if you find out please let me know.

Thanks Rocks

popeye13433

First off this is my first post as i am a new used jeep owner.

I am experiencing the same issues with my 1995 Grand Cherokee 4.0L 2x4. so far i have completed CPS with a BWG (borg warner) sensor from advanced. Also new plugs, wire, and oil change. didnt have a cap in stock so that is next.

symptoms If you turn key to start she will just crank and not fire over. you can smell gas and the check engine light will flicker. This is for the first start of the day or if she has been sitting for a while.

Another note if you turn key on you can hear the ASD relay clicking. if you allow this to go on for about 5 min she will fire right up once the clicking stops.

xKHANx

Wow 95's must be falling apart this week.

We just had the 4WD Jamboree here in Indianapolis so I cleaned up my 95 and gave it a bath on Thurs. Drove it to work then home. Early Sat I went out and wrote For Sale on the windows, ect, with some white shoe polish and went in and woke the wife up to follow me over to the church that most people would be driving by to get to the fair grounds. Got in and went to start it and no spark, turned over perfect, just wouldn't start.

Car wash must have gotten some water in the old coil wire because I swapped it out first and tried it and it fired right up I wound up swapping out the coil and plug wires and it starts like a champ now.

rompnXJ

long shot, but i remember my '94 would crank but not fire (no spark) when the TPS took a crap; the obd1 4.0's wont run without a TPS signal. test the TPS or swap it out with a known good sensor.

and yes the sync sensor is the cam position sensor. its a flat doughnut lookin thing with a magnet on the bottom of it; located right under the distributor cap

belvedere

maybe check the wiring to the CPS