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05 lly cranks but will not run and no codes

9K views 5 replies 2 participants last post by  DualThreat 
#1 ·
Hey ya'll I got a hold of a 05 LLY that wont run and wont throw any codes. I'm getting actual rail pressure @ around 9MPa and I am getting crank and cam sensor signals while its turning over but no puffs or smell or any sign of life. Truck hasn't run in about 2 years and it hasn't ran correctly in about 5 years. Got fresh set of batteries and the filter looks fresh.

Is there a down and dirty way of determining if the CP3 is bad. The truck has had a set of injectors put in sometime in its life. And a lot of shade trees have been working on it.

Let me know something
 
#2 ·
9 MPa is only 1305 lbs pressure-- the Duramax needs about 4,000 to start. If the engine does not turn over fast enough, it will not build pressure.

Possible the FPRV is bleeding off pressure-- do the bottle to check for fuel leak. Maybe someone tried to shim it.

Here is some info on the "Bottle Test".

On the drivers side fuel rail-- to the back and next to the Turbo, you will see a "U"
shaped 3/8 hose-- remove the hose from the fuel rail-- and plug the hose.

Now attach a 3/8 hose to the fuel rail nipple, and stick the end in a bottle. Now drive the truck hard-- with several wide open runs-- if there is any fuel in the bottle the FPRV [fuel pressure relief valve] is leaking main pressure from the fuel system.

The FPRV is a plug looking part that screws in the back of the driver's fuel rail. Many just increase the pressure with a couple washers, to help hold the pressure. Others use a "Race" plug [not recommended] available from supporting vendors. Forget about the driving- this is a cut and paste.
 
#3 ·
Check the FICM harness-- It is secured at the side of the alternator with a Zip tie. Cut the tie and pull the wires out. inspect carefully. Be sure you insulate the harness from the bracket, as the whole problem is the FICM bracket has a sharp edge and cuts into the wires.
 
#4 · (Edited)
Ok lets continue. 1st a little background. This is a 05 LLY extended cab 2500. Pretty much a code 1 truck. No power windows or locks, no cruise. It does have A/C. The owner states that early in the trucks life, it had gotten a tank full of kerosene. Anyway a local fuel injection rebuilder place changed all 8 injectors to the tune of about 6K. He said that the OC (oxidizing catalyst) has been punched thru. I can see that the EGR has been completely removed and blocked. NO FINGER STICK just a plug dangling. He said that the tank had been removed and cleaned. He said that the last time the engine had run was 2 years ago and the last time it had ran CORRECTLY was about 5 years ago. He also said that the last lime it ran, they had started it on ETHER. He was running a made in Taiwan fuel filter with no name on it. I pumped the hand primer till it got hard and noticed a leak around the top O ring so I changed the fuel filter out with a AC Delco filter. The old filter had water in it. I cleaned and checked the WIF sensor and made sure that it worked. And it does. I have a China T2 and I have a '04 GM service manual. All 29 pounds of it. It covers the LATE '04 which has the LLY.

I am not sure if there was THAT MUCH DIFFERENCE between a late '04 LLY and a '05 LLY. But this is what I have to work with.

JC,
I checked the FICM harness connector and the connection is good, no cuts.
 
#5 · (Edited)
I have followed the DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS flow chart in the manual though to step 5 where it THEN directs me to another flow chart called ENGINE CRANKS BUT DOES NOT RUN. There, I am directed to the following tests using the China T2.

1. Diagnostic System check YES
2. DTCs NO
3. Fuel leak or smell fixed YES
4. static fuel rail pressure 1.6Mpa range is 1-1.8 YES
5. IGN1 signal BAT VOLTAGE
6. check for fuel in oil and specific gravity of fuel no fuel in oil, didn't check specific gravity... looks, smells, feels, and tastes like diesel.
7. prime the hand primer to 8 psi it gets hard
8. wait 2 minutes and see if there is 2 psi at the test port stuck a screw driver in the test port and got a face full of spray
9. compression test ok I didn't have my compression tester so I skipped this
10. did any cylinders emit fuel vapor during compression test? skipped that one too... However I never got any fuel haze or vapor or smell out the exhaust pipe the whole time we were grinding on it.
11. crank for 15 seconds and observe actual fuel rail pressure about 9Mpa the value is 10
12. pump hand primer while starting engine no start

Go to FUEL SYSTEM DIAGNOSIS HIGH PRESSURE SIDE.
Ok this is where I had to stop... it looks like the this is where I check for leakage at the fuel pressure relief valve or excessive fuel return from injectors with the 4 graduated cylinders and hoses.


After piddling with the thing yesterday for about 2 hours, My friend decides that he wants to hear it run so he breaks out the WD40 and ETHER. He slowly introduces this mixture thru the resonator hose and finally it lights off and runs like poop. STILL NO CODES!
Yes I checked the MIL light and it does work. The balance rates are off the chart on #6 and 7 (15) the rest were all -5

#6 & 7 really weren't hitting at all

I warmed the truck up and moved it in the yard and tried to restart right after shutting it down, and it would not restart. Spins really free.
 
#6 ·
JC,
With respect to step number 11 above, the book says and I quote " 11. The engine will not run without an actual fuel rail pressure more than 10 MPa (1450 psi)."

This is a screwy way of putting it.

The engine is spinning over plenty good
 
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