All,
Thank you for reading my post. I have a Jeep that will not start. My
wife went out today, started the jeep, ran it for about 10 seconds and
then shut it off to come back inside to get something she forgot.
When she tried to start the Jeep again, it would turn over but would
not start. The weather is cold (for Atlanta) about 40 degrees F when
this happened. This particular Jeep has always been slow to start, in
the morning, year round, since we've had it.

The Jeep is a 1990 Jeep Cherokee Laredo with a straight six. It has
210k miles on the original engine. (This engine has not been
rebuilt.)

What I've tried with no success:
Start the Jeep normally.
Leave key in run position and hold down gas pedal for one minute then
try to start.
Remove and clean all spark plugs. (They each had a coating of fine
black powder.)
Test the number one cylinder for spark. (There is spark)
Test the fuel rail for pressure. (I don't have a gauge so I simply
removed the cap and depressed the little pin. The pressure was there
when I pressed the pin and pressure returns when the engine is turned
over.)
Check all fluid levels.
Try starting with oil fill cap removed.
Try starting with no air filter installed.

Is it possible that when the engine is started that the car is in open
loop, gas is dumped into the cylinders, it being cold the gas was
still liquid and did not vaporize, and now I have a flooded engine
that I need to let sit for a long time before trying to start again?

I'm out of ideas. Please help me if you can.

-Chris

If you were flooded, the plugs would be obviously soaked. When you turn
the key to run, do you hear the pump whir a bit?

Older Jeeps are really picky about having enough power to the body.
Without it, they will turn over fine, but not fire up. I would try a
boost to see what happens. I even put the boosting negative clamp on
the body to see if that helps.

If it starts with a boost, then it's time to clean the connections. The
wire mesh cable from the back of the engine head to the firewall is one
that rots out.

There also are a bunch of relays under a cover by the battery. I would
be checking them for bad connections too.

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)

Fake Name wrote:

Mike,
First, let me thank you for repling to my post. Second, I went out
and tried jumpering the neg terminal to both the body and frame with
jumper cables and it's still not starting. The engine turns over at
the same speed as normal with or without the jumper cables. I
recently replaced the neg cable and though you nailed it for sure.
(Actually I thought you had identified me making a poor contact with
the neg cable :P )

My magic eight-ball and reading historical posts here leads me to
believe that the TDC sensor is too weak to start the Jeep any more. I
tried a shot gun approach after I posted my first post in this thread.
I replaced the plugs, plug wires, cap and button.

The Jeep has air and the compression can't have gone down too much
from one start to the next. It has fuel. I'm focusing on spark.

I'm reading all posts related to the TDC sensor and will follow up
with my progress here.

Thanks again!!!!




On Sat, 09 Dec 2006 17:48:27 -0500, Mike Romain <romainm (AT) sympatico (DOT) ca>
wrote:

On Sat, 09 Dec 2006 15:03:01 -0500, Fake Name <fakename (AT) fake (DOT) com>
wrote:

Remove all the spark plugs. Use an oil sqirt can, pump about 4 sqirts
of oil in each hole. Wind it over with plugs out a few turns.
Replace spark plugs and then try.

Sounds like you have run the cyl. walls dry with gasoline wash and
have lost compression past dry rings. Pull the dipstick and smell
the oil. Smells too gassy - get the oil changed.

Pete

The CPS or top dead center sensor on those is a failure point and is on
the drivers side bell housing at the top. You can clean it's electrical
connection and see what happens. I use a spray contact cleaner on mine,
but WD40 will work in a pinch.

Mike

Fake Name wrote:

Oh, did you also put a boost on it?

My wife's 88 Cherokee up and died yesterday with a blown idler pulley.
I replaced the pulley and it wouldn't start. Fan belt had been slipping
so the battery didn't have a 'full' charge, but enough to 'appear to'
crank the starter over ok.

It 'was' turning over and not appearing to have a dead or dying battery,
but I tried a boost anyway. Bingo, it fired right up. Started this
morning in the cold ok too.

Mike

Fake Name wrote:

On Sun, 10 Dec 2006 12:53:45 -0500, Mike Romain <romainm (AT) sympatico (DOT) ca>
wrote:



Yes I did and I yanked the battery and left it on the automatic
battery charger/tester over night. The rotational speed of start is
the same with just the Jeep's battery or with another car's or with
the start boost assist from the charger.

Thanks again, Mike

Are you getting power to the coil when the starter is running? The
power to the coil comes from the starter relay on the fender. This
relay is at the end of the smaller battery positive cable. The wires
that get dirty connections and cause no spark are the green ones I
think.

You 'can' bypass this relay and give the coil direct power with a jumper
wire. You just won't be able to turn it off if it starts until you
disconnect the wire.

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)

Fake Name wrote: