I have a 97 Jeep Grand Cherokee, 93,000 miles and it would not start this morning. Recently replaced the battery and has ran fine for about 2 weeks. Its getting fuel to the fuel rail, but no fire at the spark plugs. I replaced the rotor and rotor cap, but no luck. After reading many forum entries, it seemed that the crankshaft position sensor resolved many problems with the cherokee not starting, so I replaced that but still no luck. I took the connector off the coil, and I have no voltage at that connector. I think I'm checking it correctly, and if I am there is no voltage going into the coil. Shouldn't there be 12V? Also checked all the fuses at the fuse block under the hood, and they all check out good. How can I verify the voltage at the coil, or what else can I check?
Pull the codes first:
Older (OBDI) models - Start with the ignition off. Within five seconds, switch the key on, off, on, off, on. ("On" is NOT "Start" and "Off" is NOT "Lock"). The "check engine" light will flash. Count the flashes. Each code is a two digit code, so a (for example) 23 would be FLASH FLASH (pause) FLASH FLASH FLASH (long pause). It will never flash more than 9 times, so watch for those pauses!
Newer (OBDII) models - Put the key into the ignition, push down the odometer reset button, then turn the key to RUN with your finger on the button - and then release the button. The odometer will go through 1111111 through 999999, then display the car's serial number. It will then show the error codes (it might show them starting with P). If this method does not work, try the OBDI method.
94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new
88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new
If it tries to turn over but doesn't catch, ignition coil.
00 4.7 Laredo...KYB gas shocks, ADDCO rear sway bar and Firestone Destination tires.
08 Z71 Suburban, front leveling kit with rear spacers. 285/65 18s Nitto TerraGrappler G2s
94 5.9 Laredo 6.5 RE lift with 35 Maxxis Bighorns
and 33 Bridgestone Duelers
Detroit and true trac
Red Jeep Club Member
Texas Jeep Owner #6
USN Jeep Club #4 http://www.kevinsoffroad.com/
Battery connections are fine. The starter turns at the proper speed to start the car.
Everything keeps coming back to the coil, and no voltage getting to it. Since I replaced the CPS, I'm wondering if that can stop the flow of voltage to the coil, if the air gap is not set right?
Also, what is the proper way to check the voltage at the coil? I'm have been disconnecting the leads going to the coil, turning the ignition to the on position, and checking for voltage. Nothing is there no matter how I hook up my meter. I know the meter is working correctly because I get 12V at the battery, and 5.10V at the CPS connector.
I think the ASD relay might be faulty. I switched the ASD and the A/C relay, along with re-connecting the CPS and coil plug sockets, and it started up after that.
It seems to not like the cold weather, so will wait a few more cold mornings (if we get anymore of those in Texas) and see if it fails again. If it does, will probably switch out all the relays just to cover my bases.
Thanks for everyone's help for now, and if I have additional problems I will reply to this post.