5.9L Stall. Crank, no start. Now it runs rough. - JeepForum.com
 
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post #1 of 9 Old 12-20-2018, 10:30 AM Thread Starter
riffraff21
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5.9L Stall. Crank, no start. Now it runs rough.

I ran into an issue a few months ago that has me confused. Here's the story from the top (sorry in advance for the novel):

August '18: I replaced the intake plenum plate/gasket on the engine (using the Hughes engine kit). The intake was removed and the coolant system was drained. When refilling the coolant system, I recall burping the system to get the air out but I have this nagging feeling I didn't burp it well enough. I also replaced the thermostat with the Hughes t-stat that opens sooner. It all went back together and ran without issue.

October '18: I hadn't driven it much more than a couple dozen miles since August. I drive the Jeep from the SE Michigan area to Sandusky, OH (a long-ish journey). Most of the drive is on the highway and the Jeep appears to be humming along. I hit traffic near my destination, it's standstill stop-and-go traffic. My high speed fan is cycling on and off (low speed does not work anymore)... nothing out of the ordinary. The temp gauge is reading nominal. Then, out of nowhere, the engine stalls. No stumble or cough, just cuts out. I try to restart but it only cranks. I call AAA and have it towed to a nearby shop and go about my day (I had stuff to do). The shop calls me later and says they hear a vacuum noise while trying to start and they think it could be a warped head (I don't hear this noise when trying to start it). I'm very skeptical but then again, maybe there was an air bubble in the coolant system that overheated one area of the head. It should be noted that the shop couldn't do a head replacement anyways so they didn't have a reason to lie to me. I'm also not spitting oil or coolant out the tail pipe nor am I consuming any.

October '18, later that weekend: I drive back down to Ohio with a WK and trailer to tow the ZJ home. Just for fun, I try to start the 5.9L... and it starts! It's running very rough but I drive it onto the trailer and shut it off. When I get home, I start it again (running rough again) and back it into my driveway. I leave it.

December '18: I finally get a day off to look at the ZJ (haven't touched it since October). I had to jump it but otherwise it fires right up. I decide to let it run to see what happens. While it's running, I burp the coolant system and top off the radiator. I let it heat up and the coolant system seems to be doing its job just fine. I even drive it around the block without issue. The one problem that I am having is that when I rev it neutral or park, the engine will stall as the engine speed falls back to idle (if I back off the throttle very slowly, I can prevent it from stalling).

I'm trying to figure out where to go from here. I replaced plugs/wires/cap/rotor a year+ ago, only a few thousand miles on it. I didn't replace the ignition coil, so I'm thinking I'll do that now. I also think I'm going to pull plugs to see what they look like (I'll post pics when I do). I have a compression tester but I haven't found the time to test it (I really hope I don't have compression issues). I am very open to suggestions/advice, otherwise I'll update this post on what I find.

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post #2 of 9 Old 12-20-2018, 11:27 AM
wingless
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Assuming functional components, the engine will purge air bubbles, once the thermostat opens.

The compression test will reveal the engine condition.

Has the spark plug wire TSB 18-48-98 been implemented?

Was the TSB for intake plenum torque implemented?

Has the fuel pressure been measured?


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post #3 of 9 Old 12-20-2018, 12:28 PM
jtec
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this is a 1998?
I do not see any info on checking and posting codes why ?

tell us if you have a scanner.

The rough idle and running = as mentioned lets look at fuel pressure
do you have a vacuum gauge?
Try the old school spray trick for a vacuum leak,
Yes I would like to see those plugs- wet, dry, black tan?
OH the concern about trapped air I agree with wingless.


FYI - an old school trick - when replacing T'stat, prop it open with an aspirin helps bleed air.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #4 of 9 Old 12-20-2018, 09:54 PM
MrRoundel
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Quote:
Originally Posted by jtec View Post
this is a 1998?
FYI - an old school trick - when replacing T'stat, prop it open with an aspirin helps bleed air.

Dang, why didn't I read this yesterday? Maybe next time I replace the thermostat in something. Cheers.

1998 Laredo 4.0L 4x4, 242 TC. Turned over 200K miles in 06/18. Original owner.
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post #5 of 9 Old 12-21-2018, 12:11 AM
GOLDWING
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Quote:
Originally Posted by MrRoundel View Post
Dang, why didn't I read this yesterday? Maybe next time I replace the thermostat in something. Cheers.
Quoting Sheldon from Big Bang Theory, "Sarcasm?"
GW

"The Dude Abides"
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post #6 of 9 Old 12-21-2018, 07:08 PM
MrRoundel
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No, not sarcasm. I'm just doing the complete cooling system in my '98. Actually I'm doing it again after the H2O pump leaked at gasket. Another thing I should have read before doing it, FSM says don't use sealant. I did, and now I'm doing the job again, and I hate antifreeze with a passion. Bloody heck.

1998 Laredo 4.0L 4x4, 242 TC. Turned over 200K miles in 06/18. Original owner.
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post #7 of 9 Old 12-21-2018, 11:32 PM
Timo_90xj
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5.2/ 5.9 magnums burp the cooling system by itself, if you follow the FSM procedure. No extra tricks needed.

Get the codes read, check fuel pressure (it needs to be steady, not jumping around wildly), make sure engine grounds are good.
5.9 E-fan motor and requires adapter pigtail can be found by googling, can't remember it out of my head. VDO PM9069 and WPT-168 or something along the lines... OEM motor has never been available separately, you have had to replace the whole assembly which always was very expensive.


Quote:
Originally Posted by MrRoundel View Post
No, not sarcasm. I'm just doing the complete cooling system in my '98. Actually I'm doing it again after the H2O pump leaked at gasket. Another thing I should have read before doing it, FSM says don't use sealant. I did, and now I'm doing the job again, and I hate antifreeze with a passion. Bloody heck.
It's been too long ago since the last time I worked on a 4.0, but I remember that some engine bolts require the use of thread sealant. Was it some of the water pump bolts or cylinder head bolts, I can't remember...
As for using sealant on the pump-to-block/ timing cover mating surfaces, I'd stick with using a high-quality gasket.

1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...


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post #8 of 9 Old 12-22-2018, 10:48 AM
V8GCZJ
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Quote:
I had to jump it

Quote:
The one problem that I am having is that when I rev it neutral or park, the engine will stall as the engine speed falls back to idle (if I back off the throttle very slowly, I can prevent it from stalling).

First make sure the battery is good (load test) and can hold a charge. The PCM need's to "learn" the iac and where to keep the idle at. This may take a few short trips. Weak or batteries that don't hold a charge the PCM has to do this each time you start it. Also remove the throttle body and clean out all the carbon(especially in the iac port). It's possible that the iac may be on it's way out. As for the cooling system drill a small hole(1/8) in the t stat and never have to "burp" it ever again. The hole lets out the air that would be trapped in the system until the t stat opens.
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post #9 of 9 Old 12-22-2018, 11:12 AM
jrcromwell
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Here is a link to the above mentioned TSB's this is the revised TSB.

http://dodgeram.info/tsb/2000/09-05-00.htm
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