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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
2000 jeep grand cherokee wont start
      #1220304 - 08/15/10 02:53 AM

I have a 2000 jeep grand cherokee laredo
it is inline 6 4.0L
it cranks and turns, sounds like alot of misfiring going on, wont start.

here is all the info I have pulled for now:
battery is good (have it charged up to 250 amp big battery charger, and more)

fuel pressure is 39psi with ignition ON, and 49psi-80psi when cranking. I also hear the fuel pump go with ignition ON, so probably good. also there is half tank of gas...when turned off, the pressure sometimes drops a psi or 2 but stays fairly steady afterwards

compression test shows 120-150psi on cylinders (I think I checked first 4)

all the fuses work (some need to be cranking, like the fuel injector fuse)

the ignition coil rail (no spark plug wires/distrib cap) works. Checked power to the rail (get 12-14v when cranking, so supposedly rail and crankshaft position sensor should be good) and also bought a new one just to be sure as I wasn't sure if it was sparking

spark plug wires are dry and black, really black (and week old)

fuel injectors get 10-13 ohms of resistance, seems to be good by what I hear

swapped around asd and tcm relay (asd for fuel injectors according to book, same thing happening)

crankcase vent valve (front one) is busted, but I wouldn't think it has any effect on starting, probably would run rougher

took off air intake/filters/air hoses, still nothing

poured a bit of gas into the throttle body, when cranks you can see a bit of fire there, but nothing

when I crank for a longer time (5 seconds) the throttle body area explodes, big poof, and one hose usually gets popped off from pressure

had 2 codes earlier when scaned, P0340 and P1391, but after deleting them 3 days ago, they havent appeared

wednesday, the car would start after 4 or 5 longer cranks (we assumed it was to get fuel pressure, were guessing fuel pump gone) and would start but would die within 10 seconds, then again after 4 or 5, and then never again (heard something blow, and it was the throttle body area mentioned). Didn't touch the car until saturday morning afterwards.

what is there left to check? could it be timing? does it use belt or chain, and would that have any impact on starting and could it be that bad off if it started earlier.
could the spark plugs be sparing too early? and dry/black, too rich, maybe there is no air? But we opened up whole throttle body and everything, took off air intakes and all, and still nothing. Could fuel filter affect even if the fuel pump seems to work and get enough pressure (hasn't been changed since bought, now has 220KM, about 135k miles). The valve, not sure whats it called but is totally broken, its like a pcv valve but its not and theres 2 of them, shouldnt affect starting I believe.

any ideas? i am really starting to be lost, I have a few ideas left, like neutral safety switch, map sensor, pcm, but there is less and less ideas as I am slowly testing everything one and twice over

edit: when cranking , or turning ignition to start, i dont hear any click of swirl sound from the injectors (should I?) as I hear them on some of my other cars

Edited by KoopaTroopa (08/15/10 03:02 AM)


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MartySoCal
Mudrunner


Reged: 05/31/09
Posts: 304
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Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220312 - 08/15/10 11:44 AM

Code P0340 is no cam sensor signal.

Code p1391 is intermittant loss of cam or crank sensor signal.

The cam sensor is usually OK, what fails is the oil pump drive seizes and rotates in the block, and/or the drive gear breaks. The oil pump drive/Cam sensor is where the distributor would be on the older version of the 4.0l. If the sensor drive gear is broken, the cam should be inspected, as sometimes it breaks the distributor drive gear cut in the camshaft. If you install a new oil pump drive, it has to be "synced" to align it to top dead cylinder #1.

Another very common failure is the Crankshaft position sensor. It's mounted on top of the transmission bellhousing, on the driver's side, near the engine block. It's held in with one bolt and reads a tone wheel on the transmission flexplate. If you have access to a scan tool, check for RPM while cranking.

Without both sensor signals, you will get no spark or injector pulse.

Hope this helps!


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: MartySoCal]
      #1220325 - 08/15/10 01:55 PM

Hiya, thanks for the response.

I was going to reply with an update on what I have planned next, and camshaft position sensor is on the list, along with the crankshaft one, testing MAP sensor, and also neutral safety switch on the starter.

I will test all that out today, I am fairly certain it is the camshaft sensor (just a hunch).

Thanks and I will update later on in the day (hopefully).


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sunder
Wheeler


Reged: 07/23/09
Posts: 111
Loc: Saratoga Spring, NY
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220332 - 08/15/10 03:32 PM

The neutral safety start would disable the starter motor, not the ignition/injection. It is there so that you don't start the jeep in gear...

I think you are on the right track with the cam position sensor. You are getting a NO/Intermittent code from the computer. Combined with the backfiring through the TB, the timing/sensor is messed up.

If Marty is right about the oil pump gear having problems you should probably pull of the distributor cap and watch the rotor turn while the engine is cranking. It would probably also help if you just try and rotate the shaft with a little force by hand (engine NOT cranking) to see if you can feel anything weird going on.

If the Cam position sensor is cheap, and you have the money, replace it.
You may also want to check to make sure that the distributor is in the correct orientation, but I'd check the simple stuff first.

--------------------
91 YJ
2 Seater Sand Rail
Handfull of other fun toys...
And a brand new, spit shined, B.S.
Oh, and a job to boot.


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: sunder]
      #1220342 - 08/15/10 07:30 PM

camshaft position sensor checks out to being ok (5v from PCM with ignition ON) and oscillates 0-5v when cranking

same with crankshaft position sensor, seems to be working too (5v from PCM ignition ON, 0-5v if you rotate engine extremely slowly)

when i reconnected the TPS (throttle position sensor) it finally gave me the sound you hear when you turn on the car, so going to try giving it a start in a bit when I put everything together, just out of curiosity.

side note: there is no distributor cap, in the inline 6 i have this "bar" which has all its coils and sparkplug wires into one. closest thing here to distrib cap is the camshaft sensor


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220364 - 08/15/10 11:30 PM

Alright, another update time.

the MAP sensor is also shot.

I tried getting a spark, connecting a sparkplug to the ignition bar to a ground and starting, no spark, so must be ignition problem.

starter, crankshaft position sensor, camshaft position sensor, battery, all work. so ASD (auto shutdown) relay or pcm?
is this a good test on the relay?
http://www.cherokeeforum.com/f2/fuel-pump-wont-turn-no-start-no-spark-27690/#post316107

i guess it is down to those 2 because i believe oil pump drive and drive gear have nothing to do with spark...

Edited by KoopaTroopa (08/15/10 11:58 PM)


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sunder
Wheeler


Reged: 07/23/09
Posts: 111
Loc: Saratoga Spring, NY
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220414 - 08/16/10 08:27 PM

I'm sorry, I didn't realize that model year was running coil pack ignition (distributorless).
So there are four good reasons I can think of that will cause a no spark condition.
1. The sensors giving your computer enough input to calculate and time an ignition curve are not there or sporadic.
2. The actuator (coil packs) that makes the spark is malfunctioning.
3. The wires leading to the actuator are messed up.
4. The computer is broken, and unable to generate or process a signal.

There are a few sensors your jeep needs to get enough info to fire a spark plug.
1. Crank position sensor. This tells the computer how fast the engine is spinning.
2. Cam shaft position sensor. This tells the computer what cylinder is where so that it can time the spark/fuel.
3. MAP sensor. This tells the computer how much vacuum is in the manifold so it can calculate what load is on the engine, and ultimately how much fuel to give it.

Considering you have test the cam and crank position sensor, I wouldn’t mess with them too much more. If you think the MAP sensor is bad, test and replace as necessary...

Have you checked the coil pack? If I remember right (not too likely) there is something like 0.8 ohms from the middle right/left to the other. It should be like middle is right/left is power to the coils, then the remaining 3 are grounds the computer pulses. On the coil pack you should measure all 3 coils and get less than 1 ohm resistance on each one....


If the coil pack checks out, I’d start suspecting and internal fault in the coil pack that lets the spark jump out before it hits the plugwire/post...

Looks like a good way to test the relay, how much does a new relay cost?

--------------------
91 YJ
2 Seater Sand Rail
Handfull of other fun toys...
And a brand new, spit shined, B.S.
Oh, and a job to boot.


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: sunder]
      #1220439 - 08/17/10 12:08 AM

Alright

my friend said before it happened the RPM went crazy and then just died.
I did test the crankshaft position sensor, but for 40 bucks i will buy it to replace and test out, if none then I will return it. I just have this gut feeling it is not the ecu because the gauges work and everything seems to work other than spark.

the coil packs (the bar with the 3 coil packs and sparkplug 'sockets') I bought a new one to check, and like the old one, both don't create sparks.

MAP sensor is good, and plus it affects fuel, not spark

so I have to check the wires up to the coil packs, and I will have to check the ASD relay, but I had one other relay identical to it, swapped them, and still nothing.

if nothing goes, then we are ordering a new ecu


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220473 - 08/17/10 12:10 PM

did a little further investigation

With the key in ignition on ON
I get no voltage to the ignition coil rail from the auto shut-down relay and power distribution center.

I checked the auto shutdown relay and it checks out good.

I guess its time to check the relay to the PCM? any tips on how to do it, doesnt say in haynes.


edit: the relay shows up at 66.4 ohms, not sure if that is good enough/close enough to the 75 ohms

Edited by KoopaTroopa (08/17/10 12:14 PM)


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sunder
Wheeler


Reged: 07/23/09
Posts: 111
Loc: Saratoga Spring, NY
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220512 - 08/17/10 07:34 PM

On your jeep, the tachometer is controlled by the PCM. To me, a freaking out tach indicates a bad sensor/bad connection to the computer.
This is how I am thinking.
1. The computer runs the tach and spark plugs.
2. The tach signal in the computer is generated based on the coil output.
3. The tach and coil are working intermittently, and linked.

Based on those three things, the PCM is trying to generate a signal intermittently.

This in combination of the p0340- loss of cam position sensor signal, and p1391 intermittent loss of cam or crank.

I decided to look up what would set those codes really quick and this is what I found...


P0340- Set condition- at least 5 seconds have elapsed with Crank position sensor signals present, but no Cam position sensor signal

AND

P1319 – set condition – crank or cam position sensor was intermittently lost 20 times for 2 “trips”

I think you really need to look into the Cam Position Sensor because...

1. Both of those 2 codes talk about the Cam Position Sensor. (one code is saying that that it is being lost, and the other saying its been lost for a while)
2. The Tach and ignition system is not functioning right.

A relay would cause the Coil’s to not fire, but wouldn’t really effect the tach. I don’t know the intimate details on how that particular computer is setup, but I bet that an intermittent flow of juice through a mosfett would not cause an internal sensor to register crazy RPM. I do bet that an intermittent signal from a cam sensor could be breaking and getting signal super quick causing a really weird sensor reading which would cause a really weird output (freaking out tach).

I forget, Have you check out the connector on the Cam Position Sensor?

The connector coming from the computer should have 3 wires... I don’t remember the order, but...
1 wire should have 5V reference voltage.
1 wire should have a good ground.
1 wire is feeding the computer with the signal from the cam position sensor.
To test for 5 volt reference from the computer...
1. Disconnect the connector
2. Turn the key to run
3. put my volt meter on DC volts
4. put my ground probe on the bat ground
5. test all 3 pins for DC
6. a pin should have 4.5-5V DC
To test for ground....
1. Disconnect the connector
2. Turn the key to run
3. put my volt meter on Ohms
4. put my ground probe on the bat ground
5. test all 3 pins for continuity
6. a pin should have practically no ohms << 1 ohm

If you have a good ground and good clean 5 volts reference, I think it is time to check the cam position sensor.
Unfortunately... You need a digital storage oscilloscope to check it right.

BUT as Marty pointed out they sometimes like to die at the oil pump. I know on some of the cars I worked on the if you remove the bolts holding the sensor you could actually see the chunk of metal that spun around and generated the signal. I’d try pulling the bolts that hold the sensor to the little stand off and see what is underneath. If you can see something that might rotate, crank the engine see if it spins, put your hand on it (not cranking) see if there is play...

Good Luck


--------------------
91 YJ
2 Seater Sand Rail
Handfull of other fun toys...
And a brand new, spit shined, B.S.
Oh, and a job to boot.


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: sunder]
      #1220537 - 08/17/10 11:17 PM

I did test the camshaft sensor earlier, but I figured why not again:

I do get a strong 5v (5.14 or so) and also a 0 ohm (well, its like 1.## or something in the connector

I opened up the sensor, rotated the engine with my breaker bar, and the pulse spins, meaning the oil drive gear spins it so its all good.

I will buy a camshaft position sensor if I can find out to try out (and return if alls well), but still only thing I am thinking is PCM, especially after I try out this new crankshaft position sensor (which I thought reads the rpm's, not the camshaft)

thanks for all advice


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sunder
Wheeler


Reged: 07/23/09
Posts: 111
Loc: Saratoga Spring, NY
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220623 - 08/18/10 08:49 PM

Crank Shaft Position sensor is the primary source for RPM data for the computer. BUT, Tach signal is usually done off Cam signal, because it is much more simple to time off of, at least historically... That said, I could be totally wrong.

You saw my justification as to why I though you should spend time on the cam position sensor. Again, my conclusions could be wrong...

You may have an intermittent signal in the wires leading to the PCM as well. If you have a pin out of the PCM connector it is fairly trivial to test for continuity between the PCM and CPS connector...

PCM's are expensive, but very reliable. I would exhaust all avenues (cam and crank sensors) before assuming a bad PCM;More so because it would be a problem with a sensor. Sensors are low voltage inputs to an analog to digital converter. Usually you have some sort of power electronic failure, like an injector/coil mosfet.

Good luck, This one is turning out to be a bear.



--------------------
91 YJ
2 Seater Sand Rail
Handfull of other fun toys...
And a brand new, spit shined, B.S.
Oh, and a job to boot.


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KF6ZPLAdministrator
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Re: 2000 jeep grand cherokee wont start [Re: sunder]
      #1220632 - 08/18/10 09:08 PM

Analog to digital conversion can be problematic.

Poor connections (loose fit or dirty/corroded contacts) can cause weird problems.

The analog voltages are low level and susceptible to resistance loss due to poor connections.

--------------------
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MartySoCal
Mudrunner


Reged: 05/31/09
Posts: 304
Loc: SoCal
Re: 2000 jeep grand cherokee wont start [Re: sunder]
      #1220806 - 08/20/10 11:35 PM

The tach signal is generated off the crank position sensor.

The PCM is probably the most relaible part in the system, very unlikey to fail.

The signals have to be read by the PCM. The sensor signals need to be checked at the PCM, if you don't have a scan tool to read the data stream.

If the cam drive is good:
90% of the time, the crank sensor is failed.

5% of the time, it's the cam sensor itself.

4% of the time, the wiring harness is broken, or it's rubbed through shorting the signal to the PCM, usually at the rear head bolt stud next to the valve cover, by the firewall.

1% of the time, it's the PCM

Hope this helps!


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: MartySoCal]
      #1220884 - 08/21/10 09:19 PM

today morning (about 10 hours ago) i got a new crank position sensor. Worked on it for a good 2 hours, finally got it off and put new one on. Now I get spark but I guess my timing is off, as it just won't start.

Will check compression again but now i have fuel and spark for sure.

thanks guys


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KoopaTroopa
Need a Spot


Reged: 05/10/10
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Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220895 - 08/21/10 11:03 PM

the recirculating valve that goes from the top (of valve cover) into the air intake/to throttlebody is gone and that is the cause of the flames and fires shooting out of the throttlebody when pressing on gas.
going to change it tomorrow (stores closed now) and hope for the best.


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MartySoCal
Mudrunner


Reged: 05/31/09
Posts: 304
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Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1220994 - 08/23/10 09:46 AM

You will need to check the sync of the cam sensor.

There is a small hole through the oil pump/cam sensor drive body that will line up with a similar hole in the rotating part under the grey plastic sensor when the engine is set to TDC Cylinder #1.

Set the engine to TDC #1. Observe the holes in the cam sensor drive to see if they line up. If not, loosen the hold down clamp and rotate the body until you can insert a toothpick, drill bit or small allen wrench through both holes. This will get it close enough to run. The cam sensor sync should be checked with a scan tool to verify that it's right at 0 degrees (TDC), but it will run "OK" +/- 10 degrees without setting a code. They do idle a bit better at 0 degrees, though.

If the oil pump drive is starting to seize, you may notice that there are witness marks on the base where the hold down clamp was originally installed, and the seizing drive has spun the itself out of position, usually the marks are about 1/4" long and will show nice shiny aluminum against the dirty part of the base. If the drive has spun, replace it and carefully inspect the camshaft gear by looking through the hole in the block at the teeth.

Hopefully, this helps!


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KoopaTroopa
Need a Spot


Reged: 05/10/10
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Re: 2000 jeep grand cherokee wont start [Re: MartySoCal]
      #1221441 - 08/27/10 01:26 AM

so I worked all bloody day on this,

took out timing chain (it was sort of loose, replaced it) and made sure the timing is right on. The compression of the first cylinder goes on right before it hits the timing mark on the dampener.

i removed the valve cover and checked the rockers and all, turned engine and when the valves open, the camshaft mark is 100% correct (used some thin allen key i had).

so, its still backfiring but the timing is perfect, and so is the camshaft position in relation to first cylinder.

i am afraid the last thing is the PCM?


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KF6ZPLAdministrator
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Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1221449 - 08/27/10 02:59 AM

Quote:

so, its still backfiring but the timing is perfect, and so is the camshaft position in relation to first cylinder.





The answer may be somewhere in the thread; however, I need to ask an obvious question....

If it is backfiring after all you have checked, what is the condition of the plugs and wires???

Backfiring is either excess gas or an accumulation of unburned gas...

Or, is it a backfire or mos-fire???

--------------------
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sunder
Wheeler


Reged: 07/23/09
Posts: 111
Loc: Saratoga Spring, NY
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1221463 - 08/27/10 07:58 AM

Have you done a leak down test to make sure your valves are sealing?

When you had the rocker cover off did you make sure that all the lifters were going equally?

I've seen a leaky intake valve cause mis firing. I've also seen flat lobes act as if it is mis firing.

Have any of your PCM codes returned?
PCM's are soo expensive and they usually don't fail. And when they do it is usually a high power driver...
The only bad PCM I've ever seen was in a caddillac seville, an injector driver just stopped working. Every other time I've seen someone replace the PCM it didn't fix anything, but it did cost a LOT.

--------------------
91 YJ
2 Seater Sand Rail
Handfull of other fun toys...
And a brand new, spit shined, B.S.
Oh, and a job to boot.


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KoopaTroopa
Need a Spot


Reged: 05/10/10
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Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: KF6ZPL]
      #1221486 - 08/27/10 11:53 AM

no wires but ignition coil rail, new, plugs are new too.

What I am thinking is the timing of the spark sent by computer is wrong.

Also, when i attachd a compression gauge, cylinder 1 would get approx 25 psi when the alignment point on the damper was maybe 30 degrees off (not too much, but it was easily seen)

backfire or misfire? well, before we had fire coming out of the throttle body, now we just get a lot of gassy pops from the throttle body, but we did unhook a lot of things (sepentine belt is off, and all attachments)

like 2 weeks ago, it would start and die within 10-15 seconds, but then there was a loud bang and hasnt started since

Edited by KoopaTroopa (08/27/10 11:56 AM)


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BigJim
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Re: 2000 jeep grand cherokee wont start [Re: sunder]
      #1221488 - 08/27/10 11:57 AM

He said he had checked the compression in the first 3 or 4 cylinders.. I'm wondering about them last 2 or 3 cylinders. He sure does write about a bad cylinder..
Big JIm

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sunder
Wheeler


Reged: 07/23/09
Posts: 111
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Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1221494 - 08/27/10 12:29 PM

The computer is digital. It will be either working or it won't. When the chips wear out they stop working, they don't slow down. If the computer is getting a signal from the sensors, generating a fuel/ignition curve then actuating the mosfet/drivers, and the actuators are functioning makes me think that the computer is doing what it is supposed to.

I would re-do the compression test and also perform a leak down test if any numbers are even a little fuzzy.
What procedure do you use to do a compression test?

Poping from the throttle body means that there is burning going on in the intake. That means there is a source of ignition present in the intake. I can think of 2 things that would light off the fuel in the intake manifold.
1. Spark Plugs. (timing)
2. Burning fuel escaping past intake valve. (valve timing/burnt valve)

The timing is controlled by the computer. If you feel that you have verified 100% correct timing on the crankshaft position sensor and the cam shaft position sensor, AND they are working perfectly. Then, it could be something very screwy going on in the computer.

A burnt valve or flat cam lob can cause the symptoms you are describing. I would run a compression test and leak down test just to be 100% sure the valves are good. I would also watch the rocker arms when cranking to check for a flat cam lobe.

I am just so leery about changing out computers. Especially because you can’t prove that it is broken except through process of elimination. I always like to find the problem and say look here is this part that is bad, I have done this test it failed, and by visual inspection you can verify it is bad. Process of elimination says look I’ve done EVERY possible think PERFECTLY and I know that this is the only other part that can be bad. There are a lot of subsystems to test to prove a computer is bad.
That said if you have the money to swap computers....

--------------------
91 YJ
2 Seater Sand Rail
Handfull of other fun toys...
And a brand new, spit shined, B.S.
Oh, and a job to boot.


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MartySoCal
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Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1221552 - 08/27/10 10:26 PM

Did you check and set the cam sensor sync? The symptoms of misalignment match what you are describing.

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KoopaTroopa
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Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: sunder]
      #1221560 - 08/27/10 10:56 PM

i will redo a compression check, and will try and build or get a leak down tester (depends on how much it would cost to buy, making seems pretty simple).

i believe the timing is dead on, why?
new timing chain, gears are aligned, and when rotating you could tell when valves go down and up. at tdc the camshaft sensor pin is 100% right on, and a new crankshaft sensor is put in (with the spacer).

last time i did compression test on all of them, they were all 100, and seemed to stay at that time

when i rotate/turn manually, it reaches 25-30psi when i turn it first time...


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MartySoCal
Mudrunner


Reged: 05/31/09
Posts: 304
Loc: SoCal
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1221586 - 08/28/10 08:38 AM

You said you changed the coil, there is a difference between the 1999 coil and the 2000+ coil, they are wired differently internally, but look identical and the connector fits. Maybe the parts store sold you the wrong one. Retry your original coil, hopefully this may be it.

Normal compression is usually over 120, usually at 140 psi. The low result may be due to a weak battery, though.


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: MartySoCal]
      #1221678 - 08/29/10 01:11 AM

alright! i will try that, sounds like something really unique (about the ignition coil)

the first time i done compression check (battery charger running at 250amps) i had 140 psi on first 4 cylinders and didnt bother checking the other 2, later on with just a battery, guess it was almost dead, was at 100 or so on all 6


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BigJim
Web Wheeler


Reged: 10/07/03
Posts: 7745
Loc: Central Texas
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1221708 - 08/29/10 12:06 PM

Quote:

alright! i will try that, sounds like something really unique (about the ignition coil)

the first time i done compression check (battery charger running at 250amps) i had 140 psi on first 4 cylinders and didnt bother checking the other 2, later on with just a battery, guess it was almost dead, was at 100 or so on all 6




Did You pull all the spark plugs before starting the compression check?
If the battery is that bad perhaps you should pull the battery out of something else and do the test with that newer battery.
Big JIm

--------------------
professional bovine relocation specialist


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sunder
Wheeler


Reged: 07/23/09
Posts: 111
Loc: Saratoga Spring, NY
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1221785 - 08/30/10 06:12 AM

If you had 100 psi min. on all 6 cyl. you probably don't have a leaking valve. Especially if you had a low battery. Marty’s solution sounds like it could be the best...

--------------------
91 YJ
2 Seater Sand Rail
Handfull of other fun toys...
And a brand new, spit shined, B.S.
Oh, and a job to boot.


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: BigJim]
      #1221804 - 08/30/10 11:41 AM

THANKYOU so much Marty and others!
it was the ignition coil! was the wrong year

THANKYOU! it started up like a charm right away!

woohoooo!


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sunder
Wheeler


Reged: 07/23/09
Posts: 111
Loc: Saratoga Spring, NY
Re: 2000 jeep grand cherokee wont start [Re: KoopaTroopa]
      #1221843 - 08/30/10 07:23 PM

SUCCESS!!!

And another win for Marty!

--------------------
91 YJ
2 Seater Sand Rail
Handfull of other fun toys...
And a brand new, spit shined, B.S.
Oh, and a job to boot.


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BigJim
Web Wheeler


Reged: 10/07/03
Posts: 7745
Loc: Central Texas
Re: 2000 jeep grand cherokee wont start [Re: sunder]
      #1221845 - 08/30/10 07:41 PM

Who'd a thunk they look the same and plugin the same and aren't interchangable? That's one for the books.
Good job Marty.
Big JIm

--------------------
professional bovine relocation specialist


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KoopaTroopa
Need a Spot


Reged: 05/10/10
Posts: 21
Loc: canada
Re: 2000 jeep grand cherokee wont start [Re: BigJim]
      #1221868 - 08/30/10 11:09 PM

if you guys ever in edmonton (Canada) I will buy you all the booze you want :)

so now I (my friend actually, his jeep) has engine light, but runs pretty well, i will be checking it in a few days and am sure it won't be too bad :)

once again, thanks!!!


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