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LLY Truck Died will crank but not start.

25K views 4 replies 2 participants last post by  Shakenbakes 
#1 ·
Alright Fellas,

So its been awhile since I posted on a forum because my trucks been a champ until yesterday. So, Saturday the 7th I got off work and my truck wouldn't start. (17 degrees outside) It was cranking kind of slow so I figured the batteries needed replaced. the truck would crank slower than normal and turn over once or twice (occasionally) but wouldn't stay running. Battery died and a coworker with a Cummins offered to give me a jump. Well it took about 20 mins of trying and it was cranking faster hooked to the other truck but would only fire a couple times and die. finally got it running and it was sounding pretty rough for a couple minutes but wasn't smoking any more than a normal cold start. Drove it home no Issues.

So I replaced the batteries 2 days later and she cranks like a raped ape again. But now it's cranking longer than the normal 2 crank start, more like 5-10 crank and start. So this Sunday 15th the wife and I took the truck out to run some errands. Cold start, 8-10 cranks and it started. Drove fine made 2 grocery stops got fuel from the same place I always go and added Power Service anti gelling treatment to the mix to see if that would help with the longer than normal cranks. we went to dinner drove home and the truck died 2/3 of the way into my parking spot and I tried to restart 3 times. It was late and Sunday so I hopped in the wifes car and picked up a new fuel filter. Changed and primed new filter like I always do, no leaks top or bottom and it still wouldn't start.

So at this point I hook the tuner up to check for codes and find nothing. truck is on stock setting. I put the key to run and check fuel pressure tuner says Actual 250ish Desired 5000ish. crank the engine and fuel pressure Actual quickly raises to 6000ish still only cranks but wont even fire once. So I remove the filter to inspect O-rings and clean and inspect the WIF. The WIF was dirty so I cleaned and I also inspected the plastic Filter Head relief screw for damage and O-Ring and found none. Reseated the filter primed it up tell fuel was gushing out smooth and clear. Opened the low presser Schrader valve on the fuel line and pumped and found I was getting clear fuel from there also.

Checked the Injector rates Saturday the 14th and everything looked good.

Checked the FICM wiring for the normal wear spots and found nothing other than it had been nicely repaired by the first owner.

Never had a RPM lope at idle. I've replaced it before because of that issue.

Checked the fuel filter head for leaks or damage and couldn't find any. I did notice the pump never gets rock solid anymore but will still pump bubble less fuel out the screw and the lower pressure fuel line Schrader valve. Re inspected and re seated filter with no improvements.

Cleaned and checked gas cap for tightness.

Checked Oil for diesel but it was good. so I don't think and injector is stuck open.

Checked all the multi color fuses with a fuse checker. all good. guess ill need to check the grey Delphi fuses next.

Check fuel lines from Filter forward didn't see any leaks but they had a braided cover over them. Haven't checked from filter back due to it being 10 degrees and a sheet of diesel covered ice now. but you would think I would see air bubbles if it was leaking and I don't.

checked and wiggle tested most of the wiring I could get my hand on. still only cranks and I cant get it to fire.

I've been leaving the block heater and charger hooked up when I'm not working on it. I've spent about 13 hours working on it since last night but now I'm at work tell 3am. its going to be a long night.

Does anyone have any ideas? I've spent about 4 hours online reading through all the forums and its mostly just things I've already tried. Any help is appreciated.
 
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#2 · (Edited)
The Engine Cranks but Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks but Does Not Run diagnostic table directs the service technician to the appropriate system diagnosis.

The Engine Cranks But Does Not Run diagnostic table assumes the following:
• The batteries are completely charged. Refer to Battery Inspection/Test in Engine Electrical.
• The cranking speed is within specifications. Refer to Engine Cranks Slowly in Engine Electrical.
• There is adequate fuel in the fuel tanks.
Diagnostic Aids

If the cause of an engine cranks but will not run condition has not been found, inspect for the following conditions:
• Hard starting only in cold ambient temperatures. These may cause an intermittent condition that may not occur in the service bay:
- Fuel heater inoperative, refer to Fuel Heater Inoperative .
- Ice blockage at the fuel pickup in the fuel tank. This will be a high vacuum in the supply lines while cranking, and the problem will disappear after the vehicle is brought in the service bay. It may also exhibit a start and stall condition or a starting condition with no acceleration.
• The correct cranking speed is 100 RPM cold and 180 RPM hot. A scan tool can be used to inspect cranking speed by pulling the ignition 1 relay and monitoring engine speed on the scan tool while cranking.
• Water or foreign material in fuel system
• A basic engine problem
• If the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor are disconnected or malfunctioning at the same time, an Engine Cranks But Does Not Run condition will exist.
Test Description

The numbers below refer to the step numbers on the diagnostic table.

5.

This step tests for an ignition 1 voltage supply to the engine control module (ECM).
6.

This step tests the 12-volt reference circuit to the CKP sensor and the CMP sensor. The 12-volt reference circuit for the CKP sensor and the CMP sensor is connected internally within the ECM. If the 12-volt reference circuit is shorted to ground, the engine will not start and no engine speed will be indicated on the scan tool.
7.

If there is fuel in the engine oil, fuel may be leaking from the fuel injector or fuel injection pump into the crankcase.
8.

If the fuel system will not even briefly prime to 10 psi and will not start, the check valve in the fuel filter/heater element housing is stuck open.
9.

This step determines if the fuel system is bleeding down causing a no start. The fuel pressure will slowly drop to 0 psi, but should still be above 8 psi 10 seconds after pressurizing the fuel system.
11.

This step determines if the problem is a stuck open or broken fuel injector. If fuel vapors come out of any of the glow plug holes, excessive fuel is being sent into a cylinder, and not being distributed to all of the fuel injectors.
12.

The engine will not run without an actual fuel rail pressure more than 10 MPa (1,450 psi).
14.

If the no-start condition takes place in cold operating temperatures, 2-4°C (35-40°F) or colder, a glow plug system failure may cause the no-start condition.
17.

In some cases, no compression, possibly with excessive fuel, in a single cylinder can cause a no start
1-

Did you perform the Diagnostic System Check - Engine Controls?

yes-Go to Step 2
no-Go to Diagnostic System Check - Engine Controls

2-


1. Turn On the ignition, with the engine OFF.
2. Observe the DTC Information with a scan tool.

Does the scan tool display DTC P0090, P0335, P0336, P0340, P0370, P0374, P0380, P0601, P0602, P0603, P0604, P0611, P0612, P1621, P1626, P1631, P1683, or U1800?

yes-Go to Diagnostic Trouble Code (DTC) List
no-Go to Step 3

3-

Is the customer's concern with a fuel smell or fuel leak?

yes-Go to Fuel Leaks
no-Go to Step 4

4-

Observe the Actual Fuel Rail Pressure parameter with a scan tool.

Is the pressure within the specified range? 1-1.8 MPa

yes-Go to Step 5
no-Go to Step 18

5-

Observe the Ignition 1 signal parameter with a scan tool.

Is the Ignition 1 signal parameter at the specified value? B+

yes-Go to Step 6
no-Go to Step 24

6-
1. Attempt to start the engine.
2. Observe the Engine Speed parameter with a scan tool while the engine is cranking.

Is the Engine Speed parameter more than the specified value? 0 RPM

yes-Go to Step 7
no-Go to Step 19

7-
Inspect for the following conditions:
• Excessive fuel in the engine oil--Refer to Fuel in Engine Oil in Engine Mechanical.
• Contaminated Fuel--Refer to Contaminants-in-Fuel Diagnosis .

Did you find and correct the condition?

yes-Go to Step 34
no-Go to Step 8

8-
1. Install the J 44638 Vacuum Gage to the fuel system service port on the right front side of the engine.
2. Attempt to hand prime the fuel manager 30 times or until the specified pressure is reached.

Can you prime the system to the specified value? 8 psi

yes-Go to Step 9
no-Go to Step 31

9-

Does the pressure measure more than the specified value for more than 2 minutes? 2 psi

yes-Go to Step 10
no-Go to Step 13

10-

Perform the Engine Compression Test. Refer to Engine Compression Test in Engine Mechanical - 6.6L. Repair the engine as necessary.

Did you find and correct the condition?

yes-Go to Step 34
no-Go to Step 11

11-

Did any of the cylinders emit any fuel vapor during the Engine Compression Test?

yes-Go to Step 28
no-Go to Step 12

12
1. Crank the engine for 15 seconds.
2. Observe the Actual Fuel Rail Pressure parameter with a scan tool.

Is the Actual Fuel Rail Pressure parameter more than the specified value? 10 MPa (1,450 psi)

yes-Go to Step 14
no-Go to Step 13

13
1. Reprime the fuel manager to 10 psi.
2. Attempt to start the engine while the prime is still above 8 psi.

Does the engine start?

yes-Go to Fuel System Diagnosis
no- Go to Fuel System Diagnosis - High Pressure Side

14-

Observe the Glow Plug System Type parameter with a scan tool.

Is the Glow Plug System Type Federal?

yes-Go to Step 15
no-Go to Step 16

15-

Important: Repeat this procedure on both banks of the engine. This test may be repeated as many times as necessary.

1. Turn OFF the ignition.
2. Connect a test lamp to a glow plug harness connector and a good ground on one side of the engine.
3. Turn ON the ignition, with the engine OFF.

Does the test lamp turn ON and OFF?

yes-Go to Step 16
no-Go to Glow Plug System Diagnosis

16

Important: If there is high resistance in the signal or low reference circuits of the crankshaft position (CKP) sensor the Engine Speed parameter of the scan tool will display a value more than 0. It will not be an accurate measure of engine speed, and can cause an Engine Cranks but does Not Run condition.

Test the CKP sensor signal and low reference circuits for high resistance. Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

yes-Go to Step 34
no- Go to Step 17

17

Inspect for the following conditions:
• A plugged air filter
• A collapsed air intake duct
• The fuel heater is inoperative. If the customer concern is that the engine will not start when ambient temperatures are less than 2-4°C (35-40°F), refer to Fuel Heater Inoperative .
• A restricted exhaust system--Refer to Symptoms - Engine Exhaust in Engine Exhaust.

Did you find and correct the condition?

yes- Go to Step 34
no- Go to Diagnostic Aids

18-
1. Disconnect the fuel rail pressure (FRP) sensor.
2. Observe the Actual Fuel Rail Pressure parameter on the scan tool.

Does the Actual Fuel Rail Pressure parameter measure more than the specified value? 175 MPa


yes-Go to Step 23
no- Go to Step 22

19.
1. Turn OFF the ignition.
2. Disconnect the CKP sensor.
3. Turn ON the ignition, with the engine OFF.
4. Probe the 12-volt reference circuit of the CKP sensor with a DMM connected to a good ground.

Is the voltage more than the specified value? 10 Volts yes-Go to Step 29 no- Go to Step 20

20-
1. Turn OFF the ignition.
2. Disconnect the camshaft position (CMP) sensor.
3. Turn ON the ignition, with the engine OFF.
4. Probe the 12-volt reference circuit of the CMP sensor with a DMM connected to a good ground.

Is the voltage more than the specified value? 10 Volts yes- Go to Step 30. no-Go to Step 21

21 Test the 12-volt reference circuit of the CKP sensor and the CMP sensor for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition? yes- Go to Step 34. no-Go to Step 33

22- Test the FRP sensor signal circuit for a short to ground. Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition? yes- Go to Step 34. No- Go to Step 33

23- Test the FRP sensor circuits for high resistance. Refer to Circuit Testing in Wiring Systems.
Did you find and correct the condition? yes- go to step 34. no go to step 25

24-
1. Test the ignition 1 voltage circuit of the engine control module (ECM) for a short to ground, a high resistance, or an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
2. Replace the fuse if necessary.

Did you find and correct the condition?

yes-Go to Step 34
no-Go to Step 26

25-
Test for an intermittent or for a poor connection at the FRP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

yes-Go to Step 34
no-Go to Step 32

26-
1. Clean and tighten the ECM shared ground. Refer to Power and Grounding Component Views in Wiring Systems.
2. Attempt to start the engine.

Does the engine start?

yes-Go to Step 34
no-Go to Step 27

27-

Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

yes-Go to Step 34
no-Go to Step 33

28-

Important: When the fuel injector pressure lines are removed, debris will fall on the fuel injector inlet fitting. Vacuum the debris from the area to prevent the debris from falling in the fuel injector.

Replace the fuel injectors on the affected cylinders. Refer to Fuel Injector Replacement .

Did you complete the replacement?

yes-Go to Step 34


29-

Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement .
Did you complete the replacement?

yes-Go to Step 34

30-

Replace the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement .

Did you complete the replacement?

yes-Go to Step 34

31-

Important: Before replacing the fuel filter/heater element housing, inspect the fuel vent screw for damage or cross threading. Replace the vent screw w/"O" ring if either condition is found.

Replace the fuel filter/heater element housing. Refer to Fuel Filter/Heater Element Housing Replacement .

Did you complete the replacement?

yes-Go to Step 34


32-

Replace the FRP sensor. Refer to Fuel Rail Pressure (FRP) Sensor Replacement .

Did you complete the replacement?

yes-Go to Step 34

33-

Replace the engine control module (ECM). Refer to Engine Control Module (ECM) Replacement .

Did you complete the replacement?

yes-Go to Step 34

34-
1. Clear any DTCs with a scan tool.
2. Attempt to start the engine.

Does the engine start and continue to run?

yes-Go to Step 35
no-Go to Step 2

35-
1. Allow the engine to idle until normal operating temperature is reached.
2. Observe the DTC Information with a scan tool.

Are any DTCs displayed?

yes- Go to Diagnostic Trouble Code (DTC) List
no-System OK
 
#3 · (Edited)
No Start or Hard Start

(1)Check the injector returns:

(2)Verify the fuel injector return line pressure is greater than 3 BAR (see “Fuel Injectors” for more information).

(3)Unplug the fuel pressure regulator 2 (pressure control valve in left hand rail) electrical connector. Crank the engine for 15 seconds and verify there is a steady flow of fuel from the fitting on the rail. If there is not, proceed to checking/replacing the high pressure pump.

(4)Remove the return hose from the fuel pressure regulator 2 (pressure control valve in left hand rail) and plug the hose. Crank the engine for 15 seconds and measure the fuel from the regulator. The volume of fuel should be less than 10 ml. If it is more, replace the regulator. The high pressure seal on the pressure control valve is one time use. Do not remove the pressure control valve unless you are sure it is defective and you are replacing it.

(5)Check for air in fuel system; install clear lines before and after the filter housing to check for air in the lines.

(6)Use a vacuum gauge to check the suction side of the fuel system. You should have no more than 5 inches Hg at WOT (wide open throttle) or 7-8 inches Hg under load. If you still have too much restriction after changing the filter, check for collapsing soft fuel lines by the drivers side valve cover and under the truck near the transmission. The fuel tank pick up may also be plugged. Too little vacuum (less than 2 inches Hg) means that it could be sucking air.
(7)Confirm actual versus desired rail pressure even under crank no start conditions, to confirm the starting issue is rail pressure related. If rail pressure matches desired, diagnose other codes that may be related to starting problems.

(1) (No Start) Disconnect the electrical connector and return line from one injector. Plug the fuel return line fitting with a suitable tool (CH-50377-A). Crank the engine for 15 seconds and verify no fuel leaks from the injector. If fuel leaks from the injector, replace it. Repeat for all eight injectors.

(2)(Hard start but runs) Disconnect the return line from one injector. Plug the fuel return line fitting with a suitable tool (CH-50377-A). Use adapter CH-50378 (required to accurately test return, contains regulator to maintain injector return pressure) to route the injector return into a graduated container. Crank or idle the engine until fuel is dripping out of the line. Crank or idle the engine for 15 seconds and measure the return quantity. If the quantity is greater than 3 ml in 15 seconds, replace it. Repeat for all eight injectors.

(8)Remove the high pressure regulator from the high pressure pump and check for metal debris. If there is metal found, the entire high pressure fuel system must be checked for metal and replaced as needed. GM recommends replacing the injection pump, rails, high pressure fuel lines, fuel injectors, fuel return rails, indirect fuel injector, and indirect injector fuel feed tubes if metal is found.
 
#4 ·
Thank you ramblinrodney.


so, I check all me fuses again today with a fuse light and everything checked good. So I decided to pull all fuel related fuses and inspect. Sure enough (1*EDU/25A) was blown but for some reason it still would light up. replaced the fuse and fired right up. Ran errands for 1.5 hours with no issues.


Stopped at the dealer so the could put their code reader on it and found out #2 and 4 glow plugs need replaced and the Glow plug controller had a circuit fault or ground fault. they checked the wires and connectors and couldn't find and issues there and recommended it be replaced. I already have the plugs so no issue there. but I guess ill be ordering a controller.


So on my way to work today about 5 miles into an 11 mile trip my truck died again. replaced the fuse and it fired right up. Now the only thing I can think of is that the first night it blew I had put the truck in 4WD to get into my driveway and it blew shortly after. Now today when I left my driveway for work I had it in 4WD and forgot to take it out and it blew on the way to work. Put the truck back in 2WD and drove the 6 miles further to work and no issues. Maybe I have some wires shorting each other out in the main harness? Ill try to leave it in 2WD and see if it happens again.
 
#5 ·
So drove home tonight in 2WD with no issue. Got stuck in my driveway put it in 4WD and it died. Blew the 25A fuse again replaced it and it fired right up. Made it kind of tricky navigating the driveway in 2WD.
 
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