Total Loss of Power - Head Scratcher

Davide33 · **Joined:** Wed Nov 25, 2020 8:44 am **Posts:** 25

CRD has been running perfectly for the last 8000 miles. Yesterday I was driving in Phoenix. I turned a corner, accelerated, and suddenly had a total loss of power. I thought the engine had quit, but when I looked down at the tach, I saw it was still running. I pretty much coasted to the next stoplight. The engine was shuddering as if it was running on two cylinders. When the light turned green, I pressed the accelerator. The Jeep didn't move but the engine smoothed out. It didn't gain RPM or start moving until I nearly had the accelerator to the floor. Then it slowly crept forward, and could very slowly get up to city speed. Each time I came to a stop the engine shuddered badly, but kept running. I was able to limp it a few blocks back home. Again, when I stopped it shuddered badly. I turned it off, and tried to re-start it, with no success. It sounded as if it was trying to start but I didn't want to press the issue. Deflated, I did the only thing I could do. I went to happy hour, fairly certain I had a major engine problem. Today I decided to take a look and see if there was anything obvious that could be causing the issue. I turned the key. It started immediately, and ran perfectly. I ran around the block a couple of times afraid to stray too far from home. I accelerated heavily several times with no issue. WTF!

Anyone have any Idea what could have caused this? At first I though of fuel starvation, but I have the Sasquatch Parts, in tank lift pump installed. When it was shuddering in my driveway I pressed on the primer pump and it was firm. So fuel starvation is unlikely. I also replaced the fuel filter 8000 miles ago. I did notice the day before, that even when I had the accelerator to the floor there was no black smoke.

8000 miles ago I replaced the following: Map Sensor, Cam Sensor, Crank Sensor, All new filters, Timing Belt, Motor Mounts, Battery, Thermostat, Air Intake Hose, Gateway Front Control Module

Any help would be appreciated!

fjdiesel · **Posted:** Wed Jun 30, 2021 11:47 am

I too am interested on what you find out was the culprit.

Davide33 · **Joined:** Wed Nov 25, 2020 8:44 am **Posts:** 25

fjdiesel wrote:

I too am interested on what you find out was the culprit.

I'm not hearing anything regarding my problem. I did however search the internet and found an instance where leaking vacuum lines were suspect. This made me think of my last vehicle, a 2000 Jetta TDI (diesel). I had a problem where it would often go into limp mode. The problem turned out to be leaking vacuum lines. I replaced them and it solved the problem. The difference is, the Jetta ran well while in limp mode, just had low power. The Jeep ran like crap. Maybe their limp mode isn't quite as refined.

I had also noticed recently that shortly after starting the Jeep, I would hear a thump coming from the dash area. It made me think, a leaking fitting could be loosing vacuum while sitting. Then, when I start the engine, vacuum is restored, causing some vacuum controlled flap in the AC system to close with a thump. It seemed to make sense.

Yesterday I looked over the vacuum lines. I didn't see any cracked lines, but did find a couple places where connections seemed loose. I replaced those lines and will hope for the best. If I have any more information, I will post it here.

WWDiesel · **Posted:** Wed Jun 30, 2021 1:38 pm

Do you have a lift pump installed?
If not, more than likely your problem is air in fuel.
Very common problem on these vehicles.
Let us know,

Davide33 · **Joined:** Wed Nov 25, 2020 8:44 am **Posts:** 25

WWDiesel wrote:

Do you have a lift pump installed?
If not, more than likely your problem is air in fuel.
Very common problem on these vehicles.
Let us know,

Yes, I have the Cummins lift pump from Sasquatch Parts.

WWDiesel · **Posted:** Wed Jun 30, 2021 3:10 pm

Davide33 wrote:

WWDiesel wrote:

Do you have a lift pump installed?
If not, more than likely your problem is air in fuel.
Very common problem on these vehicles.
Let us know,

Yes, I have the Cummins lift pump from Sasquatch Parts.

OK, any codes set? Problem may be electrical?

Davide33 · **Joined:** Wed Nov 25, 2020 8:44 am **Posts:** 25

WWDiesel wrote:

Davide33 wrote:

WWDiesel wrote:

Do you have a lift pump installed?
If not, more than likely your problem is air in fuel.
Very common problem on these vehicles.
Let us know,

Yes, I have the Cummins lift pump from Sasquatch Parts.

OK, any codes set? Problem may be electrical?

No Codes. It seems to be running great now. I did notice that since I replaced some vacuum lines, The thump I'd been hearing from the dash on startup is gone.

WWDiesel · **Posted:** Thu Jul 01, 2021 5:23 pm

Davide33 wrote:

No Codes. It seems to be running great now. I did notice that since I replaced some vacuum lines, The thump I'd been hearing from the dash on startup is gone.

When I replaced all my vacuum lines, I used silicone hoses which are impervious to heat, cracking, and collapsing.
FLEX TECH SILICONE HOSES & TUBES

I found some of the OEM tubing cracked and heat had cause one of them to be partly flattened out and kind of crimped.
I also split the vacuum system at the brake booster source and ran separate hoses one for the turbo controls and another one for the HVAC system.
This upgrade also improved turbo responsiveness.
See this:

Total Loss of Power - Head Scratcher

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