TJ 4.0L engine just cuts out

psl53

Registered User
I have 57,000 miles on my 99 TJ 4.0 L. When wheeling in Moab and for the first time had a problem with my TJ. After the engine has been running for a while, very warmed up, but not overheating, running normally the engine just cuts off. It won't start until I sit and let everything cool down. I'm not getting spark. I'm going to re-check tomorrow, I'll check the fuel pressure and see if I can get spark, but I'll have to run it a while. anyone have any Ideas, some mentioned the ignition module, but a 99 has no such part. Any help will be appreciated.
Thanks
Peter
 

Dana

Member
Location
Jamaica Beach
A friends TJ kept starting/stopping due to a dying fuel pump. The filter was totally clogged up as well. Its in the fuel tank, requires dropping tank. The Jeep would run, then die. He;d sit for a few minutes and it would start up for a few more miles until it finally died altogether.
 

waynehartwig

www.jeeperman.com
Location
Mead, WA
Ignition pick up?

Coil you can test with an ohm meter.
CPS will usually throw a code if it's not functioning.

I'd start with the ignition pick up as it's only ~$40
 

RockChucker

Well-Known Member
Location
Highland
mine had the same problem, but it would do it at random times while i was cruising on the freeway. it turned out to be the fuel pump. but like you said it could be your coil. how long has it been since you changed spark plugs, cap and rotor and/or sp wires?
 

psl53

Registered User
Changed spark plugs, distrub cap, router and wires only 4000 miles ago. What is the ignition pick up? and the coil has two up and down pins and a center one that goes sideways, the secondary side is the one that the coil wire connects. Does anyone know which ends the ohm meter + and - connects to.
Thanks
Peter
 

RockMonkey

Suddenly Enthusiastic
If you're not getting spark that would rule out the fuel pump/filter, wouldn't it? I don't think there is a fuel pressure sensor that would kill the spark if there's a lack of fuel pressure, but I could be wrong. In my experience this is either a crank position sensor (most likely) or a coil. If it's a Jeep you're planning on keeping for a while I'd just go buy a coil and a CPS. I'd say it's about a 90% chance it's one of those two, and they're both really good spares to have around.
 

tagaustatoppen

1997 TJ
Location
Heber, Utah
If you're not getting spark that would rule out the fuel pump/filter, wouldn't it? I don't think there is a fuel pressure sensor that would kill the spark if there's a lack of fuel pressure, but I could be wrong. In my experience this is either a crank position sensor (most likely) or a coil. If it's a Jeep you're planning on keeping for a while I'd just go buy a coil and a CPS. I'd say it's about a 90% chance it's one of those two, and they're both really good spares to have around.

My friends xj would not start we changed everything i could think of. it still wouldnt start finally we changed the fuel pump and it started right up. no codes... I would not have believed it if i didnt witness it.
 

waynehartwig

www.jeeperman.com
Location
Mead, WA
Changed spark plugs, distrub cap, router and wires only 4000 miles ago. What is the ignition pick up? and the coil has two up and down pins and a center one that goes sideways, the secondary side is the one that the coil wire connects. Does anyone know which ends the ohm meter + and - connects to.
Thanks
Peter

THe pick up is inside the distributor, under the cap/rotor.
 

Marshall

Was That a U-Joint?
Location
Farmington, UT
I'd put my 5 dollars on the CPS... (the "Crap we're Pretty Stranded" sensor)..as it has come to be known in my book of lessons learned the hard way.
 

1993yj

.
Location
Salt Lake
In my experience with bad coils, when mine went out, it would not start at all, even after sitting for hours. IF it happens to be the coil, make sure you get a replacement one from the dealer, the aftermarket ones last for about a week.
 

mbryson

.......a few dollars more
Supporting Member
I'd put my 5 dollars on the CPS... (the "Crap we're Pretty Stranded" sensor)..as it has come to be known in my book of lessons learned the hard way.

In my experience with bad coils, when mine went out, it would not start at all, even after sitting for hours. IF it happens to be the coil, make sure you get a replacement one from the dealer, the aftermarket ones last for about a week.



Get the DEALER CPS (or any other electrical sensors). DO NOT GET ONE FROM AUTOZONE, CHECKER or wherever. (just my personal, expensive, painful experience)


Oh, and I vote for the CPS. Sounds exactly like my 4.0L XJ acted when it was acting up. I had NO codes either (nor does my PowerJoke when it loses a CPS)
 

psl53

Registered User
Well, I screwed up, I ordered on line as they were a third of the cost. Thought the dealer was hosing me. Maybe I'll go on line and try to find less expensive OEM parts.
Thanks for the help.
Peter
 

BumpaD_Z28

Member
Location
Logan, UT
Well, I screwed up, I ordered on line as they were a third of the cost. Thought the dealer was hosing me. Maybe I'll go on line and try to find less expensive OEM parts.
Thanks for the help.
Peter

Do you have the part # for the OME sensor (CPS) I'm thinkin' I need to budget picking one up as a spare for my '01 TJ ...

THANKS ~DaVe
 

Devel

Just an Outlaw....
Location
North Salt Lake
Check to see if any wires have burned on ur exhaust, it could be ur Auto Shutdown Relay (ASD in ur fuse box) that has tripped. if not that i would say its ur CPS
 

Cody

Random Quote Generator
Supporting Member
Location
Gastown
I kept burning out coils (4 in 2 weeks, 3 of them in 12 hours). Id' be running down the freeway and it would die. the cps was testing ok. I would change a coil, it would run for a bit, then do it again.

I changed the cps anyway, and have never had a problem since.
 
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