Re: 96 Grand Cherokee Stalling
 

dougguitar wrote:

> DougW, question: You said if the distributor rotor moves from side to
> side, it's shot. By side-to-side, I assume you mean motion from the
> center of the rotor towards the outer diameter of the distributor
> (i.e., along the length of the rotor). Mine has maybe a little over a
> 1/16" of play in that direction. Is that a concern? Could that cause
> my symptoms?

Yep, radial movement. ( o )
<-|->

There is another movement, axial. where you hold the rotor down
and slowly rotate it clockwise/counterclockwise. It shouldn't move
up and down.

Make sure your grabbing the metal shaft and not the plastic rotor.
1/16 is quite a bit. That definitly could be causing your problems as
it has a great effect on timing. Is there a lot of oil in the bottom
of the distributor?

It might also explain the problem when hot because the bushing is
worn and oil will work its way up in there and cause arcing. The
inside of a distributor should be bone dry.

might want to read here.
http://revbeergoggles.com/distributor/

I wasn't having stalling but the motor did feel like it wanted
to jump out of the mounts at certain RPMs. Replacing the
distributor didn't fix all the problems but it did run a lot
better.

Hate to say "throw more parts at it" but sometimes that's the only
way. There is no real diagnostics for the spark side under load
unless the shop has a rolling road. I'm still in the process of
throwing parts at my 93. :) But then again if I wanted it to run
like new I'd be buying new.

--
DougW
Jeep mechanics is like a murder mystery where someone kills your wallet.

Re: 96 Grand Cherokee Stalling
 

dougguitar wrote:

> DougW, question: You said if the distributor rotor moves from side to
> side, it's shot. By side-to-side, I assume you mean motion from the
> center of the rotor towards the outer diameter of the distributor
> (i.e., along the length of the rotor). Mine has maybe a little over a
> 1/16" of play in that direction. Is that a concern? Could that cause
> my symptoms?

Yep, radial movement. ( o )
<-|->

There is another movement, axial. where you hold the rotor down
and slowly rotate it clockwise/counterclockwise. It shouldn't move
up and down.

Make sure your grabbing the metal shaft and not the plastic rotor.
1/16 is quite a bit. That definitly could be causing your problems as
it has a great effect on timing. Is there a lot of oil in the bottom
of the distributor?

It might also explain the problem when hot because the bushing is
worn and oil will work its way up in there and cause arcing. The
inside of a distributor should be bone dry.

might want to read here.
http://revbeergoggles.com/distributor/

I wasn't having stalling but the motor did feel like it wanted
to jump out of the mounts at certain RPMs. Replacing the
distributor didn't fix all the problems but it did run a lot
better.

Hate to say "throw more parts at it" but sometimes that's the only
way. There is no real diagnostics for the spark side under load
unless the shop has a rolling road. I'm still in the process of
throwing parts at my 93. :) But then again if I wanted it to run
like new I'd be buying new.

--
DougW
Jeep mechanics is like a murder mystery where someone kills your wallet.

Re: 96 Grand Cherokee Stalling
 

dougguitar wrote:

> DougW, question: You said if the distributor rotor moves from side to
> side, it's shot. By side-to-side, I assume you mean motion from the
> center of the rotor towards the outer diameter of the distributor
> (i.e., along the length of the rotor). Mine has maybe a little over a
> 1/16" of play in that direction. Is that a concern? Could that cause
> my symptoms?

Yep, radial movement. ( o )
<-|->

There is another movement, axial. where you hold the rotor down
and slowly rotate it clockwise/counterclockwise. It shouldn't move
up and down.

Make sure your grabbing the metal shaft and not the plastic rotor.
1/16 is quite a bit. That definitly could be causing your problems as
it has a great effect on timing. Is there a lot of oil in the bottom
of the distributor?

It might also explain the problem when hot because the bushing is
worn and oil will work its way up in there and cause arcing. The
inside of a distributor should be bone dry.

might want to read here.
http://revbeergoggles.com/distributor/

I wasn't having stalling but the motor did feel like it wanted
to jump out of the mounts at certain RPMs. Replacing the
distributor didn't fix all the problems but it did run a lot
better.

Hate to say "throw more parts at it" but sometimes that's the only
way. There is no real diagnostics for the spark side under load
unless the shop has a rolling road. I'm still in the process of
throwing parts at my 93. :) But then again if I wanted it to run
like new I'd be buying new.

--
DougW
Jeep mechanics is like a murder mystery where someone kills your wallet.

Re: 96 Grand Cherokee Stalling
 

dougguitar@yahoo.com wrote:

> I'm almost at the point of throwing in the towel and taking it to a
> shop for diagnosis, but I hate to start paying someone else to guess at
> the problem.

More times than not, decent mechanics will have seen the problem before
and have a pretty good idea what is causing it. Often, if they do pin
it down to couple of things, they will change something out and if the
problem is something else, they will reinstall the original part and not
charge you for it. Many use databases that collect information from
others with the same problem, and look up the solutions in those cases
for clues to your mystery. I don't have a problem paying someone to
research this stuff: there's no point in reinventing the wheel.

If it makes you feel any better, think of all the money you've saved on
DIY maintainance and such already; at some point, you have to give a
little back when a real head-scratcher comes along. Better: think of
how NICE it will be when the big-guys solve the problem and it runs like
it should for a change!

Re: 96 Grand Cherokee Stalling
 

dougguitar@yahoo.com wrote:

> I'm almost at the point of throwing in the towel and taking it to a
> shop for diagnosis, but I hate to start paying someone else to guess at
> the problem.

More times than not, decent mechanics will have seen the problem before
and have a pretty good idea what is causing it. Often, if they do pin
it down to couple of things, they will change something out and if the
problem is something else, they will reinstall the original part and not
charge you for it. Many use databases that collect information from
others with the same problem, and look up the solutions in those cases
for clues to your mystery. I don't have a problem paying someone to
research this stuff: there's no point in reinventing the wheel.

If it makes you feel any better, think of all the money you've saved on
DIY maintainance and such already; at some point, you have to give a
little back when a real head-scratcher comes along. Better: think of
how NICE it will be when the big-guys solve the problem and it runs like
it should for a change!

Re: 96 Grand Cherokee Stalling
 

dougguitar@yahoo.com wrote:

> I'm almost at the point of throwing in the towel and taking it to a
> shop for diagnosis, but I hate to start paying someone else to guess at
> the problem.

More times than not, decent mechanics will have seen the problem before
and have a pretty good idea what is causing it. Often, if they do pin
it down to couple of things, they will change something out and if the
problem is something else, they will reinstall the original part and not
charge you for it. Many use databases that collect information from
others with the same problem, and look up the solutions in those cases
for clues to your mystery. I don't have a problem paying someone to
research this stuff: there's no point in reinventing the wheel.

If it makes you feel any better, think of all the money you've saved on
DIY maintainance and such already; at some point, you have to give a
little back when a real head-scratcher comes along. Better: think of
how NICE it will be when the big-guys solve the problem and it runs like
it should for a change!

Re: 96 Grand Cherokee Stalling
 

Well, I thought I had the problem nailed. Last night, I started it up
and decided to try the wire wiggling that someone had suggested. I
wiggled the wire leading to the coil, the plug wires, the sensors on or
around the distributor. Nothing happened.

Then I said "Hmm, what's this big ol' wiring harness back here?" I
jiggled it around. *stumble cough sputter* The engine started to
hiccup! I pushed on it again, and the engine stalled. Aha! I've found
it. It turned out to be one of three wire harnesses that hook directly
to the ECM. So I took out the coolant bottle and removed the little
plastic cover over the ECM connectors.

The ECM itself is held to the firewall by three screws. One of mine was
(and currently still is) totally missing. A second one was just kind of
hanging in there not really holding it securely. When I pushed on any
of the three wire harnesses, though, the engine would sputter and even
die if I kept pushing on it. I could jiggle them around some more and
then I'd be able to restart the engine.

So I removed the three connectors, and sprayed everything down with my
handy dandy contact cleaner, replaced the connectors, and securely
tightened my two remaining bolts to hold the ECM on the firewall. I
started it up, and jiggled the wires, but now the engine just kept
purring away. Sweet!!! I put everything back in place, did some more
jiggling of the wire harnesses, but the engine kept running fine. Took
her for a test drive of about five miles, and everything was great.

I took the kids to school in it this morning, then headed on in to work
(about 20 miles). Ran great, no problems. Leaving work this evening,
though, less than a mile down the road, bam, it stalled out again! Talk
about the agony and the ecstasy!

I got out (in the rain of course) and jiggled my wires around. It
didn't want to restart. Kept pushing the wires in various ways, and
trying to restart, and finally got it going. I went 40 feet and stalled
again. Repeat the push-jiggle-start routine a few times and it finally
started up. I was then able to drive it the rest of the way home
without incident.

So now what? I guess something else is either loose, shorted or
otherwise electrically hosed. I guess I'll continue to try to push and
jiggle more wires to try to get it to stall and locate the problem.

Should I look into replacing the wire harnesses? That looks like a
nightmare as a DIY job. I couldn't even find any online sources of
places to buy wire harnesses. It's probably some little short or
something somewhere, but how to find it? Could it be that the ECM
itself is hosed?

This GC certainly has its share of weird little electrical issues. For
example, you know how the instrument lights and odometer and all will
dim slightly when you turn on the headlights? Well, for as long as I've
owned it (8 years) that dimming effect will sometimes happen despite
the headlights not being on. About 5 or 6 months ago, the little trip
computer in the overhead console just stopped responding to either the
Step or US/M buttons. It's perpetually stuck on the Distance To Empty
reading, which works, but I can't change it to show temperature, trip
miles or anything else.

Such fun.

Doug B.

Re: 96 Grand Cherokee Stalling
 

Well, I thought I had the problem nailed. Last night, I started it up
and decided to try the wire wiggling that someone had suggested. I
wiggled the wire leading to the coil, the plug wires, the sensors on or
around the distributor. Nothing happened.

Then I said "Hmm, what's this big ol' wiring harness back here?" I
jiggled it around. *stumble cough sputter* The engine started to
hiccup! I pushed on it again, and the engine stalled. Aha! I've found
it. It turned out to be one of three wire harnesses that hook directly
to the ECM. So I took out the coolant bottle and removed the little
plastic cover over the ECM connectors.

The ECM itself is held to the firewall by three screws. One of mine was
(and currently still is) totally missing. A second one was just kind of
hanging in there not really holding it securely. When I pushed on any
of the three wire harnesses, though, the engine would sputter and even
die if I kept pushing on it. I could jiggle them around some more and
then I'd be able to restart the engine.

So I removed the three connectors, and sprayed everything down with my
handy dandy contact cleaner, replaced the connectors, and securely
tightened my two remaining bolts to hold the ECM on the firewall. I
started it up, and jiggled the wires, but now the engine just kept
purring away. Sweet!!! I put everything back in place, did some more
jiggling of the wire harnesses, but the engine kept running fine. Took
her for a test drive of about five miles, and everything was great.

I took the kids to school in it this morning, then headed on in to work
(about 20 miles). Ran great, no problems. Leaving work this evening,
though, less than a mile down the road, bam, it stalled out again! Talk
about the agony and the ecstasy!

I got out (in the rain of course) and jiggled my wires around. It
didn't want to restart. Kept pushing the wires in various ways, and
trying to restart, and finally got it going. I went 40 feet and stalled
again. Repeat the push-jiggle-start routine a few times and it finally
started up. I was then able to drive it the rest of the way home
without incident.

So now what? I guess something else is either loose, shorted or
otherwise electrically hosed. I guess I'll continue to try to push and
jiggle more wires to try to get it to stall and locate the problem.

Should I look into replacing the wire harnesses? That looks like a
nightmare as a DIY job. I couldn't even find any online sources of
places to buy wire harnesses. It's probably some little short or
something somewhere, but how to find it? Could it be that the ECM
itself is hosed?

This GC certainly has its share of weird little electrical issues. For
example, you know how the instrument lights and odometer and all will
dim slightly when you turn on the headlights? Well, for as long as I've
owned it (8 years) that dimming effect will sometimes happen despite
the headlights not being on. About 5 or 6 months ago, the little trip
computer in the overhead console just stopped responding to either the
Step or US/M buttons. It's perpetually stuck on the Distance To Empty
reading, which works, but I can't change it to show temperature, trip
miles or anything else.

Such fun.

Doug B.

Re: 96 Grand Cherokee Stalling
 

Well, I thought I had the problem nailed. Last night, I started it up
and decided to try the wire wiggling that someone had suggested. I
wiggled the wire leading to the coil, the plug wires, the sensors on or
around the distributor. Nothing happened.

Then I said "Hmm, what's this big ol' wiring harness back here?" I
jiggled it around. *stumble cough sputter* The engine started to
hiccup! I pushed on it again, and the engine stalled. Aha! I've found
it. It turned out to be one of three wire harnesses that hook directly
to the ECM. So I took out the coolant bottle and removed the little
plastic cover over the ECM connectors.

The ECM itself is held to the firewall by three screws. One of mine was
(and currently still is) totally missing. A second one was just kind of
hanging in there not really holding it securely. When I pushed on any
of the three wire harnesses, though, the engine would sputter and even
die if I kept pushing on it. I could jiggle them around some more and
then I'd be able to restart the engine.

So I removed the three connectors, and sprayed everything down with my
handy dandy contact cleaner, replaced the connectors, and securely
tightened my two remaining bolts to hold the ECM on the firewall. I
started it up, and jiggled the wires, but now the engine just kept
purring away. Sweet!!! I put everything back in place, did some more
jiggling of the wire harnesses, but the engine kept running fine. Took
her for a test drive of about five miles, and everything was great.

I took the kids to school in it this morning, then headed on in to work
(about 20 miles). Ran great, no problems. Leaving work this evening,
though, less than a mile down the road, bam, it stalled out again! Talk
about the agony and the ecstasy!

I got out (in the rain of course) and jiggled my wires around. It
didn't want to restart. Kept pushing the wires in various ways, and
trying to restart, and finally got it going. I went 40 feet and stalled
again. Repeat the push-jiggle-start routine a few times and it finally
started up. I was then able to drive it the rest of the way home
without incident.

So now what? I guess something else is either loose, shorted or
otherwise electrically hosed. I guess I'll continue to try to push and
jiggle more wires to try to get it to stall and locate the problem.

Should I look into replacing the wire harnesses? That looks like a
nightmare as a DIY job. I couldn't even find any online sources of
places to buy wire harnesses. It's probably some little short or
something somewhere, but how to find it? Could it be that the ECM
itself is hosed?

This GC certainly has its share of weird little electrical issues. For
example, you know how the instrument lights and odometer and all will
dim slightly when you turn on the headlights? Well, for as long as I've
owned it (8 years) that dimming effect will sometimes happen despite
the headlights not being on. About 5 or 6 months ago, the little trip
computer in the overhead console just stopped responding to either the
Step or US/M buttons. It's perpetually stuck on the Distance To Empty
reading, which works, but I can't change it to show temperature, trip
miles or anything else.

Such fun.

Doug B.

Re: 96 Grand Cherokee Stalling
 

dougguitar wrote:

soooo close. At lest you have a better idea of what is wrong.

Might try wiggling again, but this time hold the harness still and
wiggle the wires that come out of it one at a time.

Inside that massive thing are several ground spices that can
corrode. I've had mine apart once already and it's a real
pain in the ass even with the wiring book.

> Should I look into replacing the wire harnesses? That looks like a
> nightmare as a DIY job. I couldn't even find any online sources of
> places to buy wire harnesses. It's probably some little short or
> something somewhere, but how to find it? Could it be that the ECM
> itself is hosed?

Dealership is the only place for that harness. :(

You need the service manual and the wiring diagrams for your Jeep.
Then with a ohm meter and ..several days.. you can go through each
wire and check.

Get some replacement wrap and tape because the stuff that's there
tends to break due to age.

--
DougW