Strange dying after startup

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

So a few times recently when I start and put in reverse the engine will suddenly die. Then i restart and I’m able to drive normal. Today it happened again at the feed store but would start for several tries. It seems almost like a key immobilizer issue or ? It’s not like fuel or anything like that the Jeep runs perfect otherwise. No codes. Any ideas?

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

I’m trying to remember if this only happened after recent software upgrade to nicks stage 4 tune with deletes.

WWDiesel · **Posted:** Sat Oct 03, 2020 8:50 am

No codes, fuel problem? Pump up fuel pressure at fuel filter next time and see if it helps.
If it does, install intank fuel pump!

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Well things are developing quickly. Went to get some stuff this AM high speed freeway no probs, got home and went out again an hour later to get some live chickens and coming home engine ran super rough, shaking, shudder, turned off OD to keep revs up which slightly helped. Limped to fuel station WOT and left running (barely) while fueling and tried as you say pumping up the fuel head and that didn’t change anything and a full tank didn’t seem to help either. Sooooooo, I do believe it’s fuel related now, but ? No smoke, coolant looks good, still no codes.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Got a new Napa fuel filter and filled it with liquimoly diesel doc and spun it on. Seems to be running okay again but that’s just from around the neighborhood so not a great test. Will keep updated.

layback40 · **Posted:** Sun Oct 04, 2020 5:39 am

Jett wrote:

Got a new Napa fuel filter and filled it with liquimoly diesel doc and spun it on. Seems to be running okay again but that’s just from around the neighborhood so not a great test. Will keep updated.

When was the previous time the filter was changed?
Rule for diesel ownership is always carry a spare filter.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

layback40 wrote:

Jett wrote:

Got a new Napa fuel filter and filled it with liquimoly diesel doc and spun it on. Seems to be running okay again but that’s just from around the neighborhood so not a great test. Will keep updated.

When was the previous time the filter was changed?
Rule for diesel ownership is always carry a spare filter.

I don’t know I think it somehow escaped me changing when I bought it several,months ago which is odd because I always change every filter and fluid with any new car.

krb · **Posted:** Tue Oct 06, 2020 7:28 am

Interesting. Several weeks ago mine did the same. Started it up, put it in reverse and as soon as I let off the brake it died... Back in park & cycled the key and mine’s been fine ever since...

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

krb wrote:

Interesting. Several weeks ago mine did the same. Started it up, put it in reverse and as soon as I let off the brake it died... Back in park & cycled the key and mine’s been fine ever since...

Yep that’s what I was experiencing, and since filter change hasn’t happened again. I’m suspicious that this might be coupled with the need for a lift pump also, but I’m not quite there yet

Rrusse11 · **Posted:** Tue Oct 06, 2020 7:50 pm

As an alternative to the expensive and involved in tank lift pump, mine came with a small inline pump. The PO (previous owner) pointed it out when I was looking at the vehicle when he was explaining the various mods he'd done. After an extended run without the engine on, the tuner was flashing the ECU, it packed it in. $25 and about 15 mins installation time, and I'm back on the road. Old fuel lines, worn O rings and leaky seals can be a source of air getting in to the system. The filter is always a good place to start.
My $.02.

geordi · **Posted:** Wed Oct 07, 2020 1:15 pm

If it stalls out when you are trying to change from reverse to drive right after starting it up - this is likely related to the drainback problem. What is amazing is that rather than diagnose and fix that WIDESPREAD issue... Chrysler actually just described it in the owner's manual and said "this is normal" like it's no big deal.

Solution is to start the engine and let it idle for about 30 seconds before trying to go anywhere, that will resolve it.

WWDiesel · **Posted:** Wed Oct 07, 2020 1:57 pm

geordi wrote:

If it stalls out when you are trying to change from reverse to drive right after starting it up - this is likely related to the drainback problem. What is amazing is that rather than diagnose and fix that WIDESPREAD issue... Chrysler actually just described it in the owner's manual and said "this is normal" like it's no big deal.

Solution is to start the engine and let it idle for about 30 seconds before trying to go anywhere, that will resolve it.

The transmission must be placed in "Neutral" during the idle time to activate the pump circuit for the 15-20 seconds before placing the transmission in a motive gear.
Leaving the transmission in "Park" does not pump up the oil circuit or alleviate the issue. :wink:

krb · **Posted:** Fri Oct 09, 2020 5:14 am

Interesting - and weird.

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

Went through this recently, and it was absolutely the drainback issue. Symptoms were similar, and replacing the transmission filters (did both while I was in there just to be on the safe side) seems to have solved the issue.

In my case, the KJ would die if put in gear (forward or reverse) without letting it first build pressure for around 20 to 30 seconds after starting. This would typically happen after parking for around four hours, with the first start of the day being a particularly delightful pain.

If ordering parts, make sure that you're getting part numbers 5179267AD for the spin-on filter and 5013470AE for the flat filter; anything prior to those may not solve the issue. It's also probably best to get the actual Mopar filters as there's no good way of knowing which version of the filters any aftermarket ones may have been based off of.

WWDiesel · **Posted:** Fri Oct 09, 2020 2:47 pm

There are two different issues at play, I will try and cover both in detail, they are separate issues but can both occur simultaneously.

The drainback issue: motive hesitation when first placing transmission in (R or D) when first starting engine after setting overnight or for an extended period of time.
Caused by ATF fluid draining back out of the ATF fluid cooler and cooling lines to/from the transmission back to the transmission oil sump.
This is an aggravation but does not really hurt anything. If you can get in the habit of starting the engine and immediately placing the transmission in Neutral (N) or simply placing the transmission in Neutral (N) before starting the engine and then allowing the engine to fast idle for 10-20 seconds before placing the transmission in a motive gear (D or R), there will be no more hesitation.
In some cases, replacing the screw on fluid filter and flat style filter in the transmission sump with genuine OEM Mopar filters will cure the hesitation, but some have done this and it did not seem to fully cure the issue. There is a so called anti-drainback (flow control valve PN: 04799681) valve in the transmission that can be replaced, but sometimes replacing it too will not always cure the issue.
A stock transmission does NOT circulate fluid in park so any extended long periods of idle should always be done in the Neutral (N) position.
The transmission VB can be modified by a rebuilder when rebuilding so that it will flow ATF in Park.

The stalling engine issue: when first starting the engine and and driving for a short distance and the engine stalls and feels like a straight shift clutch not releasing.
Two possibilities for this one:
1) First, the dipstick is not reliable! The problem can simply be caused by the transmission fluid level being underfilled. A low fluid level can cause air bubbles to get entrained in the fluid and cause an imbalance of pressures in the torque converter lock-up clutch. As a result, the clutch disengages improperly (late) causing the engine RPM to undershoot or in worse cases stall. Check the transmission fluid level and adjust to a higher level, it should be overfilled to about 1/2" to 3/4" above the full mark on the dipstick. These are big transmissions and and are most happy when overfilled.
2) It could be a sticking TCC switch valve. Unfortunately this valve is inside the transmission Front Oil Pump Assembly and can only be accessed after removing the transmission. There are some bores and plungers in the front pump assembly (see picture below) that wear out over time and can stick causing the torque converter lockup clutches not to release properly when coming to a stop and stall the engine.
The standard and best repair for this issue is to replace the complete Front Pump Assembly. There is also another control solenoid, the TCC/LR solenoid, which is part of the TRS/solenoid pack inside the transmission. This same solenoid sends pressure to the LR clutch, depending on the solenoid switch valve position in the valve body, and also to the TCC control valve. But the majority of the time, the Front Pump Assembly is the culprit causing the stalling issue.
There may be some other issues that can cause this problem, but these are the main ones we have became aware of through experiance of owners reporting on LOST. :wink:

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

That's a good point, and one that I'd overlooked - our KJ has the revised front pump, which went in at the same time as the Suncoast torque converter. Didn't even cross my mind that it was in there, but it does definitely help along with using the correct filters.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

I haven’t had it happen since the filter change but I’m not ready to say that was for sure the cause just yet. I don’t drive a lot so it takes a while to really confirm a repair sometimes. I am curious about this fluid level stuff tho. I filled it to the full mark and then added another full quart but that seems a little iffy on capacity. Plus I have a bigger remote cooler so my capacity is different than stock. I’d sure like to know what the ideal level is, in actual real numbers.

krb · **Posted:** Sat Oct 10, 2020 6:58 am

Wow, lots of good info. Thanks.
Is the spin-on filter an external filter? What's the change schedule for the tranny filters?

layback40 · **Posted:** Sat Oct 10, 2020 7:44 am

krb wrote:

Wow, lots of good info. Thanks.
Is the spin-on filter an external filter? What's the change schedule for the tranny filters?

Spin on is inside the pan next to the main one.
Filters should be changed when ever the trans fluid is changed. See the owners book for when to do it. depends on how you use your jeep.

geordi · **Posted:** Sat Oct 10, 2020 6:59 pm

Both filters are in the pan. The change interval is every 40k miles. If you are only doing mostly highway, you can probably push that to 50k.

Strange dying after startup

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