HELP!!!!! Cherokeee wont start.

[Ecomike]

I poured in an addative (heat) after the first time it acted up. Ive got good flow at the rail (psi unknown). Do you still think theres a need to drop the tank and dump out $30.00 of fuel. The last two days have been nice here, above freezing :sunshine: . What about the cps?
Thanks

Is it just hard starting, or completely dead, wont start at all anymore?

If it starts at all anymore, how well does it run once it starts?

 

[goodburbon]

if it won't start at all anymore double check plug wire order.

 

[Flash]

I just bought a 1999 cherokee sport 4.0l auto 4wd stock. It started and ran fine until the other night when it was -8. It cranked and cranked and finally started after about 15 mins, I thought the battery was going to die. The next day the same thing started all day no problem the at night it took about 15 min. and finally fired. WTF, So i decided to change all fluids and plugs, wires, cap, and rotor. Didnt help and now it wont start at all. It has spark, and when spraying either into air intake, nothing. WTF, This is my dd so help is seriously needed. Any ideas welcome. Im entertaing fuel pump relay but i dont want to just start replacing things that are good.
Thanks

:dunno:

It quit running after you did the tune up.......dubble check every thing.........if it's just flooded them remove the inj wire from the inj and crank and hopefully start it, then it will die, then reconnect the inj wire and keep it running.

 

[HOPPER]

It would start fine during the day and at 2:30 in the morning it was very hard to start, 10 min. of cranking. Now it wont start at all. I already double checked everything and ill do it again. Its almost like its flooded, but how do you flood a fuel injected motor? This morning I went out and tryed again pedle to the floor cranked for about 10 sec. and it almost started. It fired long enough to sputter. I did this two or three times with no luck and at the end of these cranking sessions ends with a loud clunk/ knock that when I let up off of key? Thats the same thing it did those two late nights except it would run after a couple sputtering attempts.
Thanks

 

[Flash]

It would start fine during the day and at 2:30 in the morning it was very hard to start, 10 min. of cranking. Now it wont start at all. I already double checked everything and ill do it again. Its almost like its flooded, but how do you flood a fuel injected motor? This morning I went out and tryed again pedle to the floor cranked for about 10 sec. and it almost started. It fired long enough to sputter. I did this two or three times with no luck and at the end of these cranking sessions ends with a loud clunk/ knock that when I let up off of key? Thats the same thing it did those two late nights except it would run after a couple sputtering attempts.
Thanks

Make sure that your oil is not over full and if it smells real strong of gas.

If it would almost start after letting it set for awhile then the inj wire remove trick should work.....and yes if it don't want to fire the fuel, and ya keep cranking it, it will just keep on dumping fuel in. once the plug is WET with gas the spark will not happen in the cylinder(gas in NOT flammable, only the vapor are) once the fuel is stopped to the cylinder it will dry enough to fire the rest of the gas.

Here is how yo find out if the fuel pump is the problem or a flooded eng in the problem............Pull a spark plug out, if it's WET then you have plenty of fuel if its dry, check power to the pump and if ya got power and ground(when cranking) then your fuel pump may be at fault.

I'm pretty sure that it is just flooded badly.

If you have washed to much gas down the cylinders and into the oil pan(remember you check the dip stick for the eng ...Right) you may have to put a fue squirt in to each cylinder to get the compression back up.

Remove the inj wire first and hold the gas peddle to the floor before you go into spending any more cash.

Flash.

 

[prostreetjeep]

if you have spark and fuel pressure and you say either wont work. try so pour fuel in to the throttle body and see if it will try to fire. be carful not to spill any anywhere.

 

[ParadiseXJ]

Turn the key to ON, not start, just ON. Wait 30 seconds. DO NOT press on gas pedal. If you have pressure at the rail, good. Turn the key to START and crank for 10 seconds or until start. Check you fuel pressure. Don't step on the gas.

Pressure?
No- it's your a.) pump b.) filter c.) relay or d.) ballast resistor.

Yes - it's not a fuel problem. Check all your plug wires. firing order is 1-5-3-6-2-4 clockwise.

 

[ParadiseXJ]

I cut myself off-

If the fuel line is always (before and after start) pressurized your pump/filter is OK.

If the line is pressurized when you turn it on and not pressurized after you've tried to start it, without stepping on the gas, it's the resistor.

If it's never got pressure, swap out the relay with a relay you know is good. If it still doesn't have pressure it's the pump.

And...last, if you did a tune up and now it doesn't start, you, just like all of us here, didn't connect something, or did it incorrectly, or you have gremlins!!

Get back to us.

 

[parkeruph]

Cylinder washout? If you are getting fuel and fire, check compression?

 

[HOPPER]

I was told the mass air flow sensor has a diode that measures air flow and if dirty will flood the engine. And theres a real big possibility the crank positioning sensor is bad, a common failure on 4.0s. I will check the plugs ie firing order. Clean the mas. and possibly replace the cps. It should have compression because it ran good before all this happened. Ill check it any way. And try and clean the fuel out of the cylinders. I think when I crankit its developing vapor lock after so many seconds and a sputter.
What do you think about the cps?

 

[Flash]

I was told the mass air flow sensor has a diode that measures air flow and if dirty will flood the engine. And theres a real big possibility the crank positioning sensor is bad, a common failure on 4.0s. I will check the plugs ie firing order. Clean the mas. and possibly replace the cps. It should have compression because it ran good before all this happened. Ill check it any way. And try and clean the fuel out of the cylinders. I think when I crankit its developing vapor lock after so many seconds and a sputter.
What do you think about the cps?

If it's trying to fire,......the cps is fine. Start with weather the spark plug is WET or not if its wet do as i have explain earlier if its dry then go back and read all the help above on fuel pump and electrical.

I think you are getting over whelmed with info and you need to right down what you need to do in order and start with the most simple free test to the more expensive aproch.........and then just focus on one test at a time its less confusing and more accurate to!



Flash.

 

[parkeruph]

When I had cylinder washout, it was because I had tried to crank it so many times while the

CPS was bad, that it washed the cyl walls clean and compression went to 0...

It had been running perfect when I shut it down the nite before. Never used any oil between changes.

The temp outside was near 0 that night. The CPS gave up because of the cold temps.

This was before my days. I called a pro mechanic and we are both scratching our heads.

He ran a compression and ALL 6 cyls read 0, yes 0, After towing it to the shop and over $300 later.

Thinking it might be the timing chain/gears.

We talked to another Jeep mechanic that told us it sounded like cyl Washout.

Well, The jeep got warm in the shop and the CPS came to life again, un-beknown to us at the time.

We took an oil squirt gun and quirted 2 squirts of reg eng oil in each cyl and replaced the plugs and turned the eng over about 3 revelutions.

Rechecked the compression and it had come up considerably. We did that 2 more times and the

compression came back up to normal, I forget the exact numbers, (getting OLD) We replaced the plugs and it fired right up.

Found out later what caused the washout, WAS the CPS. It finally give up completely.

Turned out, a wire in the CPS harness had seperated. NOT evident looking at it, NO melting, NO cracks.

We took 2 large needles and pinned each end of the wires and checked with a OHM meter to find the break.

This may or may NOT be your problem. The CPS plays tricks on you. Sometimes U got fire to the plugs and sometimes U don't.

Still, it could be the COIL, but I would lean toward the CYL WASHOUT and a intermittant CPS.
GOOD LUCK!

 

[JEEPNICK]

You should not touch the gas pedal when starting a FI motor. Just turn the key, and crank for no more than 5 seconds at a time. More will overheat the starter and shorten its life. You may also wet the new plugs and foul them even before the motor starts making it necessary to replace them again.

 

[Flash]

You should not touch the gas pedal when starting a FI motor. Just turn the key, and crank for no more than 5 seconds at a time. More will overheat the starter and shorten its life. You may also wet the new plugs and foul them even before the motor starts making it necessary to replace them again.

I agree......but when a fuel inj motor is floored(IN cranking mod) the computer shuts off the injectors........but when the eng start to trys to start or RPM reaches a level the computer starts firing the injectors again.

SO when it's trying to start the rpm is raised and the injectors start to fire again, causing it to over fuel the already flooded eng and your back to a no start:doh:

parkeruph: I agree with ya 100 percent! and the cold failing crank sensor could be part of the problem......but when it is trying to start, the CPS is working and when he as check spark it is working. Ok I agree with 99.5 percent of your post. and the way that you explained it was a lot more understanding then I:worship:


Flash.

 

[dutchjeep]

Hopper,

I flooded my engine (by cranking for just a minute, max) pretty recently (Flash knows all about it) and even after sitting over night it wouldn't start. I just glanced through your thread, but did you actually get the plugs out? In anyway a good idea, clean 'm, dry 'm, and if they're wet crank the engine a couple of times without the plugs and the injectors disconnected. I used my wife's blow dryer on the cylinders after the cranking to get an extra edge. It did it for me and it may be worth a shot before doing the more advanced stuff. Just my $0.02. Good luck!

Tim

 

[HOPPER]

Right on guys. Yes it getting a little over whelming. I think ill try and pull plugs and dry out cylinders, check compression.
Thanks

 

[HOPPER]

Well i pulled the plugs deushed them off with brake clean, held the throttle wfo cranked for a few secs. blew all 6 cylinders out with compressed air and no luck. Bought a CPS $41.00 NAPA. Going to try it first thing in the morning.
HOPPER

 

[Flash]

Well i pulled the plugs deushed them off with brake clean, held the throttle wfo cranked for a few secs. blew all 6 cylinders out with compressed air and no luck. Bought a CPS $41.00 NAPA. Going to try it first thing in the morning.
HOPPER

Were the plugs wet, do ya still have spark?

Buy your self a compression gauge if your going to getting the CPS.......Have ya look to see how much fun they are to replace...Yet :gonnablow .......makes sure you have a u-joint and a long extention.....thay could be a torques socket
Check it all out so you only have to make one trip to the parts store.

O ya and if the plug were wet with gas............you had better get some oil and a filter!


Flash.

 

[parkeruph]

Did you do a compression test?

If there is low compression, then putting a new

CPS may not make it start until you get the

compression up. Don't be dis-appointed if it

doesn't start after installing the new CPS. You

need good compression before it will start.

 

[HOPPER]

I got the old cps off after 2ft. of extensions a universial and a 11mm.
The new cps has a different plug. :doh: I guess theres a different p# for auto and manual. As far as compression my gauge will not thread into the plug holes. Its a cheapie. I dont know if i have spark anymore, I dont see why not. I dont have anyone to turn the key untill sat. Ill try it again tommorow.

Thanks, HOPPER