HELP 1997 GC - Turn over won't start - Told to come over here?

malcolmwolfe · 11-03-2009, 03:53 AM

Do not know where else to post won't let me???

1997 Grand Cherokee Laredo 4L 6 cyl

Bought beginning of spring.

Love the truck parked the night before and would not start the next day...

1) Would turn over but not start.
2) After turning key all lights and bells go off as regular start up except

a. gauges not working
b. gas light comes on with Bing and stays on (have gas though!)
c. will not give any codes

3) TESTS done so far...

Battery good
Checked all relays and fuses all good
No security issues
no ground to pump from relay, but pump works on separate power source.
unplugging pcm does not make a difference either in or out

4) past work done:

beginning of summer installed stereo but all good no problems

Water pump blew beginning of august all good sents

Fixed leads to battery a few weeks before it not working, due to a charge issue. Batttery gauge spiked to 18 v and down battery had a low cell. Changed battery at that time. Was all good with new battery, checked all with meter.

I am a FT single parent just laid off due to medical issue, so really like to get this figured out.

Thanks,
Steve.

reekor · 11-03-2009, 07:48 AM

Sounds like a toast "Crankshaft Position Sensor". Next to the oil filter there is a plug for the Crankshaft Position Sensor, unplug it and see if your gauges start working and at this point your pcm should start working as well. Don't try to start the engine. If the gauges start working replace the sensor.

Jeep n NY · 11-03-2009, 08:08 AM

Check ALL fuses in the power distribution center behind the battery. There's a 20A in there that can cause similar issues. Mine was blown due to the wiring harness connector to the rear O2 sensor being broken which allowed the wires to get chewed up by the driveshaft.

malcolmwolfe · 11-03-2009, 02:39 PM

Once again please read info, it says all relays and fuses are good, thanks???

Quote:

Originally Posted by Jeep n NY

Check ALL fuses in the power distribution center behind the battery. There's a 20A in there that can cause similar issues. Mine was blown due to the wiring harness connector to the rear O2 sensor being broken which allowed the wires to get chewed up by the driveshaft.

malcolmwolfe · 11-03-2009, 02:43 PM

Finnaly something that sounds like it makes sents. I'm going over now... I'll try this also I'm going to try to trace the ground from the pmc seems anything that the pmc grounds is not working...

malcolmwolfe · 11-03-2009, 05:06 PM

Quote:

Originally Posted by reekor

Sounds like a toast "Crankshaft Position Sensor". Next to the oil filter there is a plug for the Crankshaft Position Sensor, unplug it and see if your gauges start working and at this point your pcm should start working as well. Don't try to start the engine. If the gauges start working replace the sensor.

You my friend are a Jeep God!!! And I humble at you wisdom, please go on...

Yes just like you said... After looking and unplugging everything but finnally found the plug.

The guages came on and even gave a code, no did not try to start like you warned.

Now how do I know if the pcm is working? Or that is what is running the guages, duh. Now to replace the sensor looks a little difficult, how do I get back there on top of the tranny case to undo the screw???

Suppose that the new one with the paper spacer has to go on just perfect to...

I'll go check out how to, after this message.

reekor · 11-03-2009, 10:11 PM

Let me tell you it's not easy being this smart, too many things in my head that give me headaches. LOL

The gauges are mostly run by the BCM via CCD "Chrysler Collision Detection" bus. When the Crankshaft Position Sensor craps out it does weird things, You will lose your fuel pump and spark as it triggers your asd relay "Automatic Shutdown Relay" so the engine does not run which all makes sense, but its also seems to lock down the PCM and BCM so you can't get engine codes. I seen it make the overhead compass go crazy and power windows even stopped working. If you never seen this kind of a thing its easy to think that the PCM or BCM failed

I used a flex-socket and a lot of extensions to get up there.

Quote:

Originally Posted by malcolmwolfe

You my friend are a Jeep God!!! And I humble at you wisdom, please go on...

Yes just like you said... After looking and unplugging everything but finnally found the plug.

The guages came on and even gave a code, no did not try to start like you warned.

Now how do I know if the pcm is working? Or that is what is running the guages, duh. Now to replace the sensor looks a little difficult, how do I get back there on top of the tranny case to undo the screw???

Suppose that the new one with the paper spacer has to go on just perfect to...

I'll go check out how to, after this message.

Logicus · 11-03-2009, 10:20 PM

Quote:

Originally Posted by malcolmwolfe

You my friend are a Jeep God!!! And I humble at you wisdom, please go on...

Yes just like you said... After looking and unplugging everything but finnally found the plug.

The guages came on and even gave a code, no did not try to start like you warned.

Now how do I know if the pcm is working? Or that is what is running the guages, duh. Now to replace the sensor looks a little difficult, how do I get back there on top of the tranny case to undo the screw???

Suppose that the new one with the paper spacer has to go on just perfect to...

I'll go check out how to, after this message.

If it is the crankshaft position sensor, it is difficult to replace, even with the 6 cylinder. I had someone do the work for me as I was out of town and I watched this guy up under it on a lift, using 6-7 extensions (looked like it anyway) and even up under the hood with only feet sticking out over the grille... The whole job was $150 and well worth the trouble I'd fave had to go through without the proper tools or the ability to lift it higher than my floor jack could dream of.

Might be easier on the ZJ, though... good luck!

THX1138 · 11-03-2009, 10:31 PM

Good stuff. Thanks, Reekor, for providing such useful information. Were you joking about the "CCD "Chrysler Collision Detection" bus."? I'm on the margins of being a network guy and this sounded hilarious to me.

Davids35121 · 11-03-2009, 11:09 PM

Quote:

Originally Posted by THX1138

Were you joking about the "CCD "Chrysler Collision Detection" bus."?

He's serious as a heart attack.

reekor · 11-04-2009, 12:26 AM

No joke, Chrysler Collision Detection is a network that connects a ton of crap together. I guess it can be said that Chrysler was years ahead of the game with the CCD bus since as of 08 all cars sold in North America must have all controllers inner connected. This new standard is called C.A.N. "Controller–area network" same idea as the CCD bus.

Quote:

Originally Posted by THX1138

Good stuff. Thanks, Reekor, for providing such useful information. Were you joking about the "CCD "Chrysler Collision Detection" bus."? I'm on the margins of being a network guy and this sounded hilarious to me.

11-03-2009, 03:53 AM	#1
malcolmwolfe Registered Join Date: Oct 2009 Posts: 5 Thanks: 1 Thanked 0 Times in 0 Posts	HELP 1997 GC - Turn over won't start - Told to come over here? Do not know where else to post won't let me??? 1997 Grand Cherokee Laredo 4L 6 cyl Bought beginning of spring. Love the truck parked the night before and would not start the next day... 1) Would turn over but not start. 2) After turning key all lights and bells go off as regular start up except a. gauges not working b. gas light comes on with Bing and stays on (have gas though!) c. will not give any codes 3) TESTS done so far... Battery good Checked all relays and fuses all good No security issues no ground to pump from relay, but pump works on separate power source. unplugging pcm does not make a difference either in or out 4) past work done: beginning of summer installed stereo but all good no problems Water pump blew beginning of august all good sents Fixed leads to battery a few weeks before it not working, due to a charge issue. Batttery gauge spiked to 18 v and down battery had a low cell. Changed battery at that time. Was all good with new battery, checked all with meter. I am a FT single parent just laid off due to medical issue, so really like to get this figured out. Thanks, Steve.

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11-03-2009, 07:48 AM	#2
reekor Registered Join Date: Aug 2007 Location: HammerTown Posts: 1,650 Thanks: 0 Thanked 13 Times in 12 Posts	Sounds like a toast "Crankshaft Position Sensor". Next to the oil filter there is a plug for the Crankshaft Position Sensor, unplug it and see if your gauges start working and at this point your pcm should start working as well. Don't try to start the engine. If the gauges start working replace the sensor.

11-03-2009, 08:08 AM	#3
Jeep n NY Registered Join Date: Nov 1999 Location: Catskills of NY Posts: 1,029 Thanks: 0 Thanked 2 Times in 2 Posts	Check ALL fuses in the power distribution center behind the battery. There's a 20A in there that can cause similar issues. Mine was blown due to the wiring harness connector to the rear O2 sensor being broken which allowed the wires to get chewed up by the driveshaft.

11-03-2009, 02:43 PM	#5
malcolmwolfe Registered Join Date: Oct 2009 Posts: 5 Thanks: 1 Thanked 0 Times in 0 Posts	Finnaly something that sounds like it makes sents. I'm going over now... I'll try this also I'm going to try to trace the ground from the pmc seems anything that the pmc grounds is not working...

11-03-2009, 10:31 PM	#9
THX1138 Registered Join Date: Oct 2009 Posts: 36 Thanks: 2 Thanked 0 Times in 0 Posts	Good stuff. Thanks, Reekor, for providing such useful information. Were you joking about the "CCD "Chrysler Collision Detection" bus."? I'm on the margins of being a network guy and this sounded hilarious to me.