DacMan

Hey all, I'm currently having an issue with my 97' inline 6 4.0 Jeep cherokee. After towing a boat about 30 miles (in 75 degree outside temp) I stopped to wash the rig, and when I went to re-start it ran like the crank postion sensor was going bad. I got it home and it cooled off, ran great on the way home the next day (towing again), got home shut it down, came back 5 minutes later, started up fine put in reverse died, and now won't start. I have no fuel pressue, gas gauge reads nothing, doesn't even come on (I know I have atleast 3/4 of a tank). And no spark. I went to read the ecm through the key on/off/on/off/on and the cel didn't even come on. I know there's atleast one code wich is a bad post-cat O2 sensor. Checked the fuel pump relay and it's fine, jumped the relay at the fuse box and fuel pump came right on, doesn't prim tho when key on. So to get to the point
Here's what I've replaced in the last 2 days:
Crank Position Sensor
Magnetic Pickup
Coil
Here's what I've replaced in past 3 months
Spark Plugs
Plug Wires
Dist. Cap
Rotor
Idle Air Control Valve
Pre-Cat O2 Sensor
Coil
Crank Position Sensor

Thanks In Advance!

DacMan

Checked ADS relay by switching it with cooling fan relay, no change.

stev-o

When u changed your cps did u tie it back away from the exhaust it could be a little close

DFlintstone

Boy...I'm still trying to get the earlier systems down...

Does your light come on, on ign? Has the "Key trick" worked for you before?

Senario...something was shorting, (an 02 heater wire or something). It was running crappy or intermittently that way. Then finally a fuse blew and you lost the whole works.

I believe I've seen posted that that rear 02 wire shorting can blow a fuse that will wreck your day. Maybe not the whole truth here since it seems you where on the way home with the boat, so maybe 1/2 your day!

DacMan

Initially I did not, I had no clue that they commonly heat up and burn out, especially when there's an exhaust leak, which I have , but the new one is tied wayyy back and I hope it lasts.

DacMan

The "key trick" has worked for me in the past, however it isn't now. The last guy to own my jeep did a poor job of tying up the o2 sensor wiring and got it wrapped up in the drive shaft, so I just zip tied the female to the transfer case. Haha it ruined my past few days but It died in the driveway so I'm lucky!

DFlintstone

No Cell at all.....I know you have a boatload of fuses. The driveway is a handy place to check them.
There are other guys here who should know better than me, but I think that rear wire shorting could blow a fuse, maybe even to the ASD relay which would shutdown everything. (or more than you would like). Doubt that should affect the light, except to make it come on of course.
I asked about the key trick because I've been told that sometime in 97 they changed to needing a reader, except you can still read the cluster....if I got that right.
Anyway hopefully you found a blown fuse by the time you read this!

Oh, and of course there is a ground wire in that mess, so it could short on that as well as any metal on the Jeep.

DacMan

Hey guys I really appreciate the help, I located the number 11 interior fuse and it was blown, replaced it and back to perfect! THANKS!

DFlintstone

And the crowd cheers! .......

I'm gonna put a , (little), feather in my cap for maybe being a little help-full with an electrical problem in an OBD-II.

DacMan

Haha I think that would be a very appropriate response!!!!

tjwalker

A blown fuse is indicative of an intermittent short circuit condition.

What circuit does this fuse control? You would be well served to know this and to explore the wiring, etc. to see if you can find out why it blew the fuse.

Otherwise, dollars to donuts.....this is extremely likely to happen AGAIN.

DFlintstone

Howdy there TJ.

I wanted to show you guys these links Laredo put together. Sort of long. I was interested in the voltage test for the 97 CPS (crank sensor!), but also (I'll give it away), at the end fuse 20 is blown. Also the front 02 wiring is fried on the manifold. I'm guessing I'm guessing the 02 sensor wire shorting power to the ASD cut the 5 volt feed to the sensors.

You seemed to have the same issue with your rear 02, but fuse 11?

EDIT, Wait! The cps info was on a 97, the sensor testing is on a 96....

Anyway, c/o Laredo> http://www.cherokeetech.com/VBull/sh...agnosis-Videos