Random hard start,randomly dies & code p0340

grr

TJ Enthusiast
Original poster
Supporting Member
Joined
Nov 14, 2016
Messages
101
Location
Texas, United States
I have a 00 TJ w/4.0l manual. 148k miles dd. Few weeks ago it didn't want to start and threw a p0340 code. After a couple starts code cleared. Few days later it just randomly dies while accelerating. Did this again on way home and threw the p0340 code again. Again after couple of starts code cleared. Died again only this time in middle of intersection. Real bad spot to not start too. Started a few times and code cleared again. Replaced cam position sensor with mopar sensor. Worked fine for a few days then started again. I've researched a ton. Some say I should replace timing set. Otherwise the jeep runs great when not dying or not starting. Any ideas?
Thanks
 
This is a tough one. I've heard of this happening before and for some it was the CPS, while others said it turned out to be their coil packs, and some even said it was an O2 sensor.

I'd be willing to bet it's the coil packs.
 
I had the same issue a while back. After the cam position sensor and crank position sensor were replaced, the check engine didn't come on anymore, but the same symptoms still existed (hard to start, missing, and finally completely shutting off) and actually continued to get worse. I don't know about pre-2000 TJs, but mine is a 2000 TJ and doesn't have your typical distributor cap/spark plug wires and coil, instead it has an ignition coil which is all one piece that attaches on top of the spark plugs and has 3 coil packs built in. I changed that out and have driven almost hundreds of miles thus far and have experienced no more problems.
 
I had the same issue a while back. After the cam position sensor and crank position sensor were replaced, the check engine didn't come on anymore, but the same symptoms still existed (hard to start, missing, and finally completely shutting off) and actually continued to get worse. I don't know about pre-2000 TJs, but mine is a 2000 TJ and doesn't have your typical distributor cap/spark plug wires and coil, instead it has an ignition coil which is all one piece that attaches on top of the spark plugs and has 3 coil packs built in. I changed that out and have driven almost hundreds of miles thus far and have experienced no more problems.

Were you getting the p340 code too?
 
It stands to reason that it would be the coil packs. As I understand, on the pre-2000 TJs with the distributors, the CPS is located inside the distributor cap. If you replace the CPS and it doesn't solve the issue, the next thing in line is the distributor cap itself.

With the 2000+ TJs it's the same thing, except they have coil packs instead of distributors. If you replaced the CPS with an OE Mopar one (good choice by the way), I'm seriously betting it's the coil packs. I'd be shocked if it wasn't.
 
I have the coil pack and replaced it several years ago, not sure how many. And I don't remember the symptoms or why I did. I guess I may try that again.
 
Did you replace it with an OE Mopar coil pack? Aftermarket brands are known to not last as long.

It could be something else, but it sure seems like it would be the coil pack since that's next in line after the CPS, especially with that P0340 code.
 
Did you replace it with an OE Mopar coil pack? Aftermarket brands are known to not last as long.

It could be something else, but it sure seems like it would be the coil pack since that's next in line after the CPS, especially with that P0340 code.

Can't remember if I used oem or not. Think I got it from rock auto.
 
In the chance that it isn't OE, then it wouldn't surprise me if it failed even after only a few years of use.
 
If you get it from http://wermopar.com it will be OE Mopar and likely a lot cheaper than your dealer. Just an FYI :D

Cheapest online dealer for factory Jeep / Mopar parts that anyone knows of!
 
If you get it from http://wermopar.com it will be OE Mopar and likely a lot cheaper than your dealer. Just an FYI :D

Cheapest online dealer for factory Jeep / Mopar parts that anyone knows of!

Thanks for the link. Forgot about that. Looked up part and it just shows the single coil pack not the 3 pack rail that I recall or the one Rook refers to in his post. $175 for a single coil sound right ?
 
Thanks for the link. Forgot about that. Looked up part and it just shows the single coil pack not the 3 pack rail that I recall or the one Rook refers to in his post. $175 for a single coil sound right ?

Wow, I hadn't looked until now, but that's expensive. If they want $175, I'll bet every other place wants $200+, since these guys are widely regarded as the cheapest.
 
The cam shaft position sensor is also part of the oil pump drive assembly.
The cam has a gear on it, that turns a gear on the cam sensor, which rotates a shaft.
The top of the shaft has a rotating disc that the sensor reads.
The bottom of the shaft inserts into the oil pump and turns it.
So if it gets bad enough, the gear will fail, the shaft wont run the oil pump, and about 2 minutes later your engine will be toast.

03 to 06 Jeeps (especially 04 and 05s) are VERY prone to have these gears prematurely wear.
There is even an official letter that was issues to dealers on this, called the E05.
For the most part, dealers seem to be replacing these under the drive train warranty.

Symptoms Include:
Ticking
Squeeking/Squealing (especially at startup)
Long Cranks to Start
Low/Rough Idle

The Cause:
Many cam sensor/oil pump drive assemblies made in 04 were defective.
They are not shimmed properly, which causes the gear to ride funny, and not mesh with the cam gear properly.
The eventually causes premature wear on the sensor gear. The cam gear is a harder metal, so typically it wont see nearly as much wear.
Which is a good thing, replacing a camshaft is about a $1100 repair.

You can pull the sensor and visibly check it yourself, BUT.
be aware that this works like a distributor cap, you have to put it back in the EXACT orientation it was.
If its turned slightly, it will be out of time with the cam, and the sensor will read wrong.

Source:

http://www.jeepinwv. com/forum/viewtopic.php?f=4&t=21232