|
compiled some troubleshooting tips-
(from Lost Jeeps CRD forum- winkster- 1st post may 20 2012)
I've had no start conditions numerous times and made a troubleshooting aid for myself because I'm an electrical engineer, not a mechanical. Here is what I've made.
Trouble Shooting Won’t Start
Symptom: CRD was running fine and died while it was running. Will crank without needing a jump (battery & Alternator are good), but won’t start. No weird noises when it cranks. This assumes you do NOT have a Lift Pump. If you do have a Lift Pump, you have the understanding to bypass the steps associated with low pressure side of the high pressure fuel pump (CP3).
1. Check fuses in the engine compartment and fuse 14 in passenger cabin.
2. Swap the relay for the fuel pump with one of the other identical relays & try it.
3. Can you pressurize the fuel filter manually?
3.a. If yes, go to 4
3.b. If no, you are out of fuel, have a leak (probably before or at the fuel filter) or a blocked line before the fuel filter.
4. Verify that the rail pressure solenoid is properly connected, CAREFULLY dis-connect it and re-connect it.
5. Disconnect the harness connector to the fuel quantity solenoid and try to start. If starts, shut it down IMMEDIATELY.
5.a. You may have bad fuel or a bad fuel quality solenoid.
5.b. If bad fuel, the injectors and the High Pressure Pump (CP3) may be bad and fail soon.
5.c. If bad fuel, you have to flush the entire system.
5.d. CP3 R&R is an eight hour job that requires most of the steps required to replace the timing belt. If you are within 30,000 miles of a timing belt replacement, include it, the bearings and water pump.
6. Replace the fuel lines going to or from or both at the fuel filter with clear hose, re-pressurize the line and see if fuel is present or has bubbles.
6.a. No fuel, you have to trouble shoot if the low pressure pump is bad or you have a blockage.
6.b. If air bubbles are present, you have to find the source.
6.c. Adding a lift pump to the tank is a good way to trouble shoot this.
7. Disconnect the fuel return hose from the fuel rail. Have someone crank the engine while you observe output running into a bottle. Fuel should NOT be coming out of the hose when cranking, only when running. If fuel is present when cranking, the Fuel Pressure Solenoid is bad.
Symptom: CRD was running fine. It was turned off and will not restart
1. Check fuses in the engine compartment and fuse 14 in passenger cabin.
2. Swap the relay for the fuel pump with the relay for the blower & try it.
3. Can you pressurize the fuel filter manually?
3.a. If yes, go to 4
3.b. If no, you are out of fuel, have a leak (probably before or at the fuel filter) or a blocked line before the fuel filter.
4. Is there air in the fuel?
4.a. Replace the fuel lines going to or from or both at the fuel filter with clear hose to see if fuel is present or has bubbles.
4.b. Bleed the fuel filterSorry for the delay, work has been busy.
5. Check is the Cam Positon Sensor.
5.a. This part used to cost $22, now it’s between $60 and $80.
5.b. You can test this with a Snap-On Tester comparing the rpm craning speed to what the Cam Position Sensor shows.
___________________________________________________________________________________
(from Lost Jeeps CRD forum- bigbillyboy- 1st post Dec 18 2010)
I'm not going to guarantee this is the approved troubleshooting method, but it worked for me.
First thing I did was upgrade filter head and install lift pump to ensure no air in fuel. Once I was positive there was no air in the system, I followed the following diagnostics, which was a mixture of info from many different sources
Following a suggestion from the guys at the cummins commonrail forums, I shot a little either into the intake and cranked it over. Doing this, the liberty started and ran fine. Under heavy load conditions, the jeep would defalt to limp mode, but it would still run.
Next step was to take off the fuel return rail and check for excessive return from one or several injectors. After removing the fuel rail, (keep it in one piece and be very gentle with the plastic fittings that clip into the top of the injector. If you break one, you get to buy the whole fuel rail for $45.00 - ask me how I know. Also, don't drop any of the clips, as they are dealer only for $50/ea, and not available locally...) I insterted a 5" long piece of clear vinyl tubing into the top of each of the injectors. I cranked for 10 seconds and looked at the levels in each tube. They were all at the same level, and about 1/4" up the tube. Which is normal. If one or more is significantly higher ( I read that it could be 3-4 inches of fuel after 10 second of cranking) then you have a failed injector preventing rail pressure buildup. This was not the case for me. Also, don't break the plastic fuel return junction (where all three fuel return lines join up) before heading to the tank, as it is dealer only and runs $97 and not available for a week. I built one out of brass fittings from home depot for about $20. Much sturdier.
Next, I reinstalled the fuel return rail, and pulled the line off of the pressure control valve at the rear of the fuel rail. I cranked for 10 seconds and had a significant amount of fuel drain out. While cranking, but not running, this valve should be held shut preventing fuel from flowing at all. In my case, the valve had failed, once replaced, the jeep started easily.
It is my understanding that if the PCV had been good, the only thing that could cause low pressure would be the CP3 pump. From my reading, the pump itself rarely fails, but the MPROP valve bolted to it fails regularly.
I was able to give the part number off the PCV to a local diesel shop and they had the part next day for $449. The dealer was a week out and $849.
I tested the components in this order as it was the best way I could figure out to determine with the highest degree of certainty which component had failed without buying needless expensive components.
Fyi, that PCV valve is a very complex item. It is a normally closed valve. It is held shut with a spring, but gets additional closing force from an electromagnet. The spring itself does not provide enough force to get the rail pressure above 5000psi. The ECM varies the current to the PCV, the higher the current, the more closing force, and the higher rail pressure. Somehow this works in balance with the ECM sending a signal to the MPROP valve which both maintain predetermined rail pressure.
Hope this helps someone.
_________________
Grid power- the one true essential
2005 Liberty CRD- ARP studs, Fumoto, Hayden FC, inline Tstat, ETechno 7v GP, Platinum P1, in-tank lift pump.
1983 Volvo D24T
1981 Volvo D24
Dodge Cummins TD
Case 580B
Mitsubishi MT180 diesel
Kubota BX25 diesel
|
Login
Register
FAQ
Search
)
