93 Jeep Grand Cherokee Cranks, But No Start

Snow did pass the time by typing:
> I only have third party keys for my 93 ZJ, the keys are just regular keys
> they are not like the new anti-theft keys.
> I would be looking at the CPS, fuel filter and engine ground strap.

Yep. The 93 did not use a chipped key. Just the IR fob.

The only reason the alarm could go off while using the key in the
drivers (or tailgate) is that the disarm switch has died. There is a
mechanical switch attached to the back end of the key core.

If the horn ain't beeping the alarm/engine kill/ isn't active.

> "Casper" wrote ...
>> Is there a way to turn off the alarm to test out the alarm system as
>> being suspect? Perhaps a fuse in the panel and/or a possible second one
>> in the factory installed systems? The alarm works fine if you use the
>> original key or electronic key, but 3rd-party made keys can
>> occasionally set of the alarm from the door key hole. The alarm never
>> goes off otherwise.
>>
>> As a side note, I only have one electronic key, and no Jeep dealer
>> service deparment could get another key attuned to the system
>> simultaneously with the existing one. Only one or the other can be
>> programmed at a time.

You can also put the alarm in test mode.
With the driver door open, Turn the ignition
off-acc-off-acc-off-acc

Now every time you open/close a sensor the horn will beep.
Test all the doors and the hood
Turn the ignition on and it will beep
Turn the key in the door (disarm) and it will beep
Same thing for the tailgate (the other disarm switch)
etc..

To disable test mode just turn the ignition to RUN
then use the remote to arm/disarm the system.


--
DougW

Add the relay to that for me.
God Bless America, Bill O|||||||O
http://www.billhughes.com/

Lee Ayrton wrote:
>
> Yes. Everything manufactured has a design life and for OEM Cherokee
> fuel pumps it seems to be around 100,000 miles. Be happy that yours
> fails to start, mine gave up the ghost on a section of highway running
> through a crack neighborhood.
>
> Yossarian, meet Snowden. Snowden, Yossarian. Yossarian here will be
> dressing the wound on your leg.
>
> In your first post you wrote:
>
> > Often if you keep turning the ignition on and off until you
> > hear the fuel pump priming(?), then on the next crank attempt, it
> > starts, but not consistantly.
>
> There's the clue you should be paying attention to, not being lead away
> by the red herrings of the battery cables (if it cranks you're already
> carrying more current than the ignition will ever need) or the blinking
> security light. If all the electrical accessories are working okay then
> grounds are low on your list of things to check.
>
> Based on my experience with my own Cherokee I'd suspect:
>
> 1. fuel filter
> 2. fuel pump
> 3. fuel sender in the tank.
>
> In my case all three gave up, in that order, within a few months of each
> other.

recheck the battery cables make sure there is new clean lead showing on them
were they contact the battery posts before anything else is done

Mike Romain wrote:

> Because the idiot light comes on, I would be suspecting the alarm first.
>
> Second I would be suspecting the body ground is dirty or has failed
> because of the 'sometimes' factor. The body can steal grounds through
> things like the gas pedal cable and brake pedal, but it is not
> consistent.
>
> Some 4.0 engines have a mesh strap from the rear of the head to the
> firewall and/or from the engine to the frame across an engine mount, but
> some Jeeps use a negative cable from the battery to the fender for a
> ground.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Casper wrote:
> >
> > My 1993 Jeep Grand Cherokee recently started having starting issues. At
> > first it would start after 2-3 tries, but now it continually takes
> > longer and longer to get it to turn over. First I thought it was the
> > battery (weak or being drained), but after a full recharge and
> > replacment, the problem persists. Cables appear fine. Jump-starting
> > will help if the battery is weak, but it still takes multiple tries to
> > get it to turn over. This morning, it took 20 minutes and at least 25
> > tries to get it to go from cranking to actually starting. Sometimes
> > during cranking the security light flashes on the dash. Sometimes you
> > hear what sounds like a solenoid(?) clicking when you turn the
> > ignition. Often if you keep turning the ignition on and off until you
> > hear the fuel pump priming(?), then on the next crank attempt, it
> > starts, but not consistantly. I'm suspicious of a short somewhere. Fuel
> > solenoid? Security system? Anyone have any ideas or suggestions?

(Optima) Battery(s), either old (fully charged) or new, the system
cranks. All cables, ground, etc., have been cleaned, checked and appear
fine.

You can hear the relays clicking when you turn the ignition to the RUN
position, but not the fuel pump, at least not all the time (hearing is
not as it used to be). Connected fuel pressure guage and no pressure
when key is in the RUN position. This should read at least 20 on the
guage. Checked the relays in the engine compartment and they get
voltage(click). Checked relay/fuse compartment and it has voltage.
Checked rear power feed line to the fuel pump (near tank) and no
voltage. My understanding is that 12v should be going to the fuel pump.
If there is 12v at the relay box, but not at the rear junction, then
where else can I check where the power in not passing through? Since
the jeep sometimes starts, then I suspect a short or "open" somewhere
between those two points?? (your input here).

One other thought... I'm not very familiar with the security system, so
is it possible it is shutting off the voltage to the fuel pump? So far
as I can tell, the SS seems to be working fine but now that I have more
test info on that, I can test that too if it is tied to the problem. I
was told the only way to turn the SS off is a trip to the dealer and
$$. I would prefer avoiding turning it off/on and keep it on for the
neighborhoods I must frequent. This problem started a few months after
I was rear-ended. Since then the rear (door, bumper and associated) has
been repaired/replaced. Although the damage did not really look bad, I
could not open the rear hatch and there was a small wrinkle in the
frame that was straightened. I am not familiar with the wiring to know
if the SS is connected to anything in the rear that could cause the
voltage to not reach the pump.

Casper did pass the time by typing:
> (Optima) Battery(s), either old (fully charged) or new, the system
> cranks. All cables, ground, etc., have been cleaned, checked and appear
> fine.
>
> You can hear the relays clicking when you turn the ignition to the RUN
> position, but not the fuel pump, at least not all the time (hearing is
> not as it used to be). Connected fuel pressure guage and no pressure
> when key is in the RUN position. This should read at least 20 on the
> guage. Checked the relays in the engine compartment and they get
> voltage(click). Checked relay/fuse compartment and it has voltage.
> Checked rear power feed line to the fuel pump (near tank) and no
> voltage. My understanding is that 12v should be going to the fuel pump.
> If there is 12v at the relay box, but not at the rear junction, then
> where else can I check where the power in not passing through? Since
> the jeep sometimes starts, then I suspect a short or "open" somewhere
> between those two points?? (your input here).

12V is not always sent to the pump.

Long story short.

- turn the key on
- pump runs for a few seconds to pressurize the system
- pump then shuts off

- engine starts
- pump turns on

Swap the AC/or/Fog and fuel pump relays and see what happens.

Here are the schematics.

http://www.revbeergoggles.com/temp/zj-13.jpg
http://www.revbeergoggles.com/temp/zj-54.jpg


--
DougW

Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
Problem perisists.
Tested rear junction with OHM meter while turning ignition to RUN
position and no voltage.

'Something' is shutting down the fuel pump. Alarms can have that
feature....

You should for sure see a voltage spike at the rear junction when the
key hits run.

I would next check right at the relay. I would look for the trigger
signal when the key hits run. If I have that, then I would be thinking
the contact in the relay box might be bad.

Could you have a bad ignition switch?

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Casper wrote:
>
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

Casper did pass the time by typing:
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

Let's go over the basics then.

From the front of the vehicle, remove the fuel pump relay
Looking into the hole:

7
|

6| -8- |10

-9-

With the ignition on, hole 7 should
have 12V from the power center fuses 3(20A) and 15(30A)
(same location as the relays)
Also check fuse2(20A), the ASD power fuse.

Hole 6 should also have 12V, if not check fuse 6(15A)

Hole 9 feeds the pump and the heated O2 sensor
(If you found blown fuses take a look at the O2 sensor
and follow the wire back along the engine to where a clip
holds it to the block, then follow that wire up to another
clip up above and forward of the engine mount. sometimes
that wire will melt and short out. That short can/will blow
fuses.)

If all looks good at this point then
Jumping pin 9 to pin 7 will turn the pump on.

You should be able to hear it or watch the fuel rail
pressure jump.

--
DougW

Ok, here's the current situation...

Tested all the relays and engine compartment fuse/relay box and they
are all fine. Checked the interior fuse panel and all is fine.
Everything in these places is getting voltage.

Here is something we (my good neighbor and I) noticed during this
testing and starting attempts...

If you turn the ignition to the RUN position, four dash lights should
come on. 1) ABS, 2) Check Engine, 3)Airbag and 4) Seatbelt.

If you turn the key to RUN, and the "Check Engine" light comes on, the
jeep will start. If the "Check Engine" light does not come on, the
jeep will NOT start. If you put the key in the RUN position and the
"check engine" light does not come on, AND you leave the key in the
RUN position, eventually the "Check Engine" light comes on and the
jeep starts. Every time the "Check Engine" light comes on, you can
hear the fuel pump prime and start the jeep, usually on the first try.

We repeated this pattern for a good 30-60 minutes, giving different
time intervals inbetween because sometimes the dash lights all come on
as they should on the first trr, and we wanted to make sure it wasn't
initial luck. We confirmed there is a definite pattern.

On the very last attempt, it took longer for the light to come on.. at
least another 20 seconds than all the other previous attempts, AND
when the "Check Engine" light came on, so did the Security light. The
Security light remains on for about 3-5 seconds and then went off.

I know the system is running checks when the light is on, and
sometimes something isn't letting it come on, ergo no checks and
nofuel priming. Anyone ever see this before?

Last note.. sometimes, and only sometimes, I hear a clicking when I
turn the key to RUN. It sounds like a circuit switching on/off. During
all this testing, I did not hear it once.



>On Fri, 17 Feb 2006 16:54:11 -0600, "DougW" wrote:
>Let's go over the basics then.
>
>From the front of the vehicle, remove the fuel pump relay
>Looking into the hole:
>
> 7
> |
>
>6| -8- |10
>
> -9-
>
>With the ignition on, hole 7 should
>have 12V from the power center fuses 3(20A) and 15(30A)
>(same location as the relays)
>Also check fuse2(20A), the ASD power fuse.
>
>Hole 6 should also have 12V, if not check fuse 6(15A)
>
>Hole 9 feeds the pump and the heated O2 sensor
>(If you found blown fuses take a look at the O2 sensor
>and follow the wire back along the engine to where a clip
>holds it to the block, then follow that wire up to another
>clip up above and forward of the engine mount. sometimes
>that wire will melt and short out. That short can/will blow
>fuses.)
>
>If all looks good at this point then
>Jumping pin 9 to pin 7 will turn the pump on.
>
>You should be able to hear it or watch the fuel rail
>pressure jump.