Help No power need advice

lacabrera · **Posted:** Thu Nov 13, 2014 8:29 am

Hi need help with bad experience. Started fine drove 1 mile than engine motor nearly died not limp mode but seem to run on 1 cylinder only. Dropped into low 4 x4 to get it off to side of the road. Lifted hood engine shacking like crazy. Shut it down thinking it was serious, about to phone for assistance tried starting it and all run as normal and drove home. No cell light. Any ideas were to start looking first?

Joe Dirt · **Posted:** Thu Nov 13, 2014 8:51 am

Mine has been doing that 2 or 3 times a year since it had 60,000 miles on it. Whenever it does it I just shut it off and restart it. A few times I had to shut it off and restart it a couple of times before it would run correct. After it restarts it will run fine. The first time it happened I checked the fuel primer, it was pressured up just fine. I have just learned to live with it. I now have 130,000 miles on it. No real problems except an EGR valve at 40,000 miles.

lacabrera · **Posted:** Thu Nov 13, 2014 10:26 am

I have a in tank fuel pump connected to the factory wiring under the rear seat. The supply is feed from the relay under the hood and I guess its controlled from the ecu. Just before it happened shut the engine down and restarted within a couple seconds, Maybe it confused the ecu and cut the power to the primer pump. :?:

papaindigo · **Posted:** Thu Nov 13, 2014 1:13 pm

This behavior is not unheard of, see chat at viewtopic.php?f=5&t=78359&hilit=engine and viewtopic.php?f=5&t=79775&p=840412&hilit=engine#p840412 . No clue why, no codes, no repeat for me as of today.

lacabrera · **Posted:** Thu Nov 13, 2014 3:51 pm

papaindigo wrote:

This behavior is not unheard of, see chat at viewtopic.php?f=5&t=78359&hilit=engine and viewtopic.php?f=5&t=79775&p=840412&hilit=engine#p840412 . No clue why, no codes, no repeat for me as of today.

Many thanks papaindigo interesting read. I thought the motor was toast when it happened, I am still amazed how it ran fine after switching off and back on again. :JEEPIN:

KD6ICZ · **Posted:** Fri Jan 23, 2015 2:37 pm

Mine has done it 3 times in the two years I've owned it. I think it only does it when I'm running the GDE Hot Tune but I can't be 100% sure about this. I normally run the GDE EcoTune FT. I asked Keith and he seems to think it is indeed electrical (a sensor or something along those lines). Like yours, mine never throws a code.

ArmyChief · **Posted:** Fri Jan 23, 2015 2:43 pm

If there is any similarity, we could get a scantool hooked up and take a snapshot when the problem happens.

Hexus · **Posted:** Fri Jan 23, 2015 3:10 pm

It's air in the fuel.

It's happened to most of us longer-owning-folk, but yeah it'll go away and leave no trace that it ever happened. It feels like the motor is coming apart and it has 0 power but then you shut it down for 20 minutes and it is like nothing ever happened.

Install a lift pump, or expect it a few times in your ownership.

ArmyChief · **Posted:** Fri Jan 23, 2015 3:19 pm

Hexus wrote:

It's air in the fuel.

It's happened to most of us longer-owning-folk, but yeah it'll go away and leave no trace that it ever happened. It feels like the motor is coming apart and it has 0 power but then you shut it down for 20 minutes and it is like nothing ever happened.

Install a lift pump, or expect it a few times in your ownership.

Hexus,

I understand WHERE the air gets in on those affected. However, how does shutting it down for 20 minutes "purge" the air out?

In my business, especially when things on these vehicles (parts & labor) can be expensive, I'd prefer to data record the PIDS and try to eliminate ANY sensor/actuator input/output before using best guess.

Thanks,

Hexus · **Posted:** Fri Jan 23, 2015 4:11 pm

ArmyChief wrote:

Hexus wrote:

It's air in the fuel.

It's happened to most of us longer-owning-folk, but yeah it'll go away and leave no trace that it ever happened. It feels like the motor is coming apart and it has 0 power but then you shut it down for 20 minutes and it is like nothing ever happened.

Install a lift pump, or expect it a few times in your ownership.

Hexus,

I understand WHERE the air gets in on those affected. However, how does shutting it down for 20 minutes "purge" the air out?

In my business, especially when things on these vehicles (parts & labor) can be expensive, I'd prefer to data record the PIDS and try to eliminate ANY sensor/actuator input/output before using best guess.

Thanks,

I understand your concern and need to diagnose the issue. It's really like trying to smell a fart in a whirlwind. You aren't going to hit this one as it happens, it's so random and vastly intermittent, it would be like going to the golf course to film a hole in one, and you only go golfing on Thursdays from 1-3 A.M.

I'm not entirely sure if it's a Vapor-Lock style situation, or just a simple combustion issue.

What I _DO KNOW_ is that I've had it happen twice to me as the only owner of mine in 8 years, and they were both completely different situation, different variables, different states of oil change, fuel filter change, etc.

Both times, it went away, same as you describe, same as I've read on here about 15 times.

If you want to chase it down, I wish you the best of luck, but my golf analogy above about sums it up. Best of luck to you, let us know what you find!

KD6ICZ · **Posted:** Fri Jan 23, 2015 9:26 pm

The original poster stated he has a lift pump installed.

lacabrera · **Posted:** Tue Jan 27, 2015 10:19 am

Hi just a quick update. The problem has nether happened again so far. My guess it was my lift pump? For some reason I recon the ECU cut power to the fuel pump (my install will not allow flow through the pump if no electrical supply) May be there is a fail safe built into the ECU to cut power to the fuel pump if it detects a fault?

racertracer · **Posted:** Tue Jan 27, 2015 11:11 am

lacabrera wrote:

Hi just a quick update. The problem has nether happened again so far. My guess it was my lift pump? For some reason I recon the ECU cut power to the fuel pump (my install will not allow flow through the pump if no electrical supply) May be there is a fail safe built into the ECU to cut power to the fuel pump if it detects a fault?

There are many posts on this. The inline lift pump has to be a flow through lift pump. A flow through lift pump allows fuel to continue to flow when and if the inline lift pump fails to deliver due to an electrical or mechanical problem such as you experienced.

Our CRD has an OEM fuel pump which mechanically pulls fuel out of the tank rather than pushes the fuel through the system as the lift pump does. Undetectable air pockets in the fueling system are one of the reasons why a lift pump is installed otherwise the OEM unit would be sufficient.

The safety feature of a flow through pump is this; If there is a problem with the pump, the flow of fuel will continue to flow via the OEM fuel pump.... The vehicle continues to run even if it may be in limp home mode.

A flow through lift pump assists with the non stop flow of fuel and will not shut down the flow if the pump fails to deliver via a check valve. When this happens the original mechanical fuel pump takes over.

Replace the inline lift pump with a flow through positive flow lift pump like this one: http://www.facet-purolator.com/posi-flo-pumps.php

I experienced this issue and learned from it.

lacabrera · **Posted:** Tue Jan 27, 2015 1:31 pm

Hi yes I fully understand the principal for using a flow through pump the only problem with them is they are unreliable. Herein Europe the use of Diesel engine cars are far greater than in the states. If the car is equipped with a in tank lift pump they are fitted with a semi high pressure pump with a bypass system at the filter head returning un wanted fuel back to the tank. Examples are Fiat ducato vans, Jeep KK CRD, Grand Cherokee 3.0 CRD these all use a semi high pressure fuel pump with a pressure release valve built into the pump. The low pressure pumps are known to fail. 8 out of 10 4 x 4 sold here will be a diesel and a more reliable lift pump had to be installed.
As you know all fuel injected gas engines use a high pressure fuel pump to deliver enough pressure for the injection system and are very reliable?

lacabrera · **Posted:** Tue Jan 27, 2015 1:49 pm

part no for WK CRD 3.0 fuel sender/pump 52090131AD the fuel pump will not free flow with out the pump running? They install them for good reason they will normally last the life span of the car.

Billwill · **Posted:** Wed Jan 28, 2015 4:12 am

lacabrera wrote:

May be there is a fail safe built into the ECU to cut power to the fuel pump if it detects a fault?

Seeing as the CRD KJ was never designed to have a fuel pump the ECU does not even know that it exists....so it does not have any fail-safe system built into the ECU.....the ECU does not have any output on its connectors to switch a pump ON/OFF.

It all depends on how the fuel pump relay was installed in the first place....I personally would take the feed to the relay from the output of the ASD relay....as long as the ASD relay is energized the fuel pump will run. :wink:

lacabrera · **Posted:** Wed Jan 28, 2015 8:00 am

Billwill wrote:

lacabrera wrote:

May be there is a fail safe built into the ECU to cut power to the fuel pump if it detects a fault?

Seeing as the CRD KJ was never designed to have a fuel pump the ECU does not even know that it exists....so it does not have any fail-safe system built into the ECU.....the ECU does not have any output on its connectors to switch a pump ON/OFF.

It all depends on how the fuel pump relay was installed in the first place....I personally would take the feed to the relay from the output of the ASD relay....as long as the ASD relay is energized the fuel pump will run. :wink:

I guess the feed under the rear seat is there for the 3.7 gas version? The fuel pump relay energises the fuel pump for about 20 seconds and turns off if the motor is not running. I guess this is a safety issue if the car is involved in an accident, motor stops and no power to the fuel pump. Connecting it to the ASD relay I guess would keep it energised?
Has any one here gone to greater lengths to find out what controls the fuel pump relay?

thermorex · **Posted:** Wed Jan 28, 2015 8:07 am

lacabrera wrote:

Hi yes I fully understand the principal for using a flow through pump the only problem with them is they are unreliable. Herein Europe the use of Diesel engine cars are far greater than in the states. If the car is equipped with a in tank lift pump they are fitted with a semi high pressure pump with a bypass system at the filter head returning un wanted fuel back to the tank. Examples are Fiat ducato vans, Jeep KK CRD, Grand Cherokee 3.0 CRD these all use a semi high pressure fuel pump with a pressure release valve built into the pump. The low pressure pumps are known to fail. 8 out of 10 4 x 4 sold here will be a diesel and a more reliable lift pump had to be installed.
As you know all fuel injected gas engines use a high pressure fuel pump to deliver enough pressure for the injection system and are very reliable?

Why don't you get an inline flow through Kennedy diesel pump? It's almost $200 but it seems to hold pretty well for me so far. I only have a bit over 50k with it, but haven't heard anybody complaining about it so far. It puts out about 5 psi.

WWDiesel · **Posted:** Thu Jan 29, 2015 12:04 am

lacabrera wrote:

I guess the feed under the rear seat is there for the 3.7 gas version? The fuel pump relay energises the fuel pump for about 20 seconds and turns off if the motor is not running. I guess this is a safety issue if the car is involved in an accident, motor stops and no power to the fuel pump. Connecting it to the ASD relay I guess would keep it energised?
Has any one here gone to greater lengths to find out what controls the fuel pump relay?

View this post to see wiring diagrams for fuel pump relay and module:
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=23099&p=856394#p856394

lacabrera · **Posted:** Fri Jan 30, 2015 1:06 pm

WWDiesel wrote:

lacabrera wrote:

I guess the feed under the rear seat is there for the 3.7 gas version? The fuel pump relay energises the fuel pump for about 20 seconds and turns off if the motor is not running. I guess this is a safety issue if the car is involved in an accident, motor stops and no power to the fuel pump. Connecting it to the ASD relay I guess would keep it energised?
Has any one here gone to greater lengths to find out what controls the fuel pump relay?

View this post to see wiring diagrams for fuel pump relay and module:
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=23099&p=856394#p856394

Hi thanks for the schematic of the wiring diagram, But its the programming side of the controller that I was wondering if any one had looked at.

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