03 Duramax. Lost prime? bad IP? won't run
 

Hello all,
As you can see I'm new to the forum. Anyways, I have an 03 Duramax, I ran it on WVO pretty much flawlessly for 2 years. Injectors went out. Had them replaced. I installed a completely different WVO system (FASS pumps on both sides, Vegtherm Mega, Premium VO controller, 2 FPHEs, plenty of filters, etc) that always ran diesel fuel over the FICM to cool it. This was an improvement over my last kit. {If your lost following the waste veggie oil stuff I'm sorry} It ran great on biodiesel/diesel over the new couple of weeks. I tried t switch to WVO and it just didn't run well. Maybe the engine was confused because the FICM was seeing one type of fuel and the IP was getting WVO. - At this point I pretty much decided that the Duramax is a great motor for diesel and biodiesel blends, but not WVO. The high fuel pressure is an issue, as well as maintanence.

I have taken everything on my Duramax back to stock. The fuel goes from the tank, to the FICM, to the stock fuel filter/water sep, into the IP, out of engine, into fuel cooler, etc,

The WVO stuff is disconnected. I am planning on getting a 12-valve cummins, all mechanical motor to run on WVO. I figure this is better suited for it.

I cannot, however, get my truck to run. The fuel filter is next to new. I have emptied the water valve. I have blow pressurized air into the tank and bled it via the valve right before the IP, I have bled from everywhere I can think of (on top of the fuel filter, etc).

I have attempted to use a little bit of starting fluid. I have pumped the primer 1000s of times. I believe I have all of the air out of the fuel, but I can't get her going again. Starting fluid can get her going for a second, but there is no pedal response. Have I done something bad? ideas?

My 03 Duramax has 122k miles, brand new injectors, plenty of mods, and is for sale...

Suggestions for getting it going?

I am looking for a 12-valve dodge with a 5 or 6 speed. Preferably 4wd, etc

Thanks SO MUCH!

Chris
(Blackburg, Va)

I have heard of over rev conditions using starter fluid on duramaxes. DO NOT DO THIS ANY MORE!!! The stories were unbelievable nightmares.

I had a similar non starting issues, but never experimented with Bio stuff. Always pump diesel.

Look at the triangle plate under your prime button. Does it look moist at all? If so there is a simple o-ring under it that fails. Use a Torx (T25 I think?) to pull it off. Be careful as the spring pressure of the prime button can/could launch the screws. Remove 2 of them and hold the button down as you do the last one. I can imagine all the different oils you might have used so far might have deteriorated that material. They do go bad but usually over 150-200K. They dont sell it at the dealer, but if you need it I can tell you what size it is or sell you one as I had to buy a bunch just to get the size I needed.

Also look at the large diameter (rubber) fuel lines that go into and out of your FICM and into the back of the CP3. Also there are 2 lines that "T" off of that fitting one goes to the bleeder one goes to the fuel return block. If any of those lines have leaks or look dry rotted, replace them, this WILL keep it from running. $25-40 in fuel lines and 4-5 hours, not fun but cheaper than other fixes. Also there is ONE more small rubber line that is buried it attaches near the end of the LAST one I described. I think there are 6 total, 3 big diameter, 1/2" and 3 small 5/16ths" dia.

Keep us posted.

Thanks ARZ,
I got the triangle off today. The O-ring looks ok. Tried pumping it hundreds of times and bleeding it. Nothing helps in getting it started so far... The lines near the FICM look to be without leaks! I may go to the local hardware store and see what they have in terms of O-rings. Any other ideas?
Thanks!
Chris

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I replaced the O-ring with a larger one. Same size inner diameter, but more material. Thicker. This did not help in getting in started. From what I have read, I am supposed to just pump the primer many, many, many times, release any air from the bleeder, and repeat until air no longer comes out. Then prime many more times and turn it over. This has not helped in getting it started. Have tried pumping compressed air into fuel tank and sealing off the fuel fill-up port with a towel, to pressurize the fuel tank and send pressurized fuel to the FICM, filter, IP, but this has not worked either.

Have you gotten it to fire at all other then with starting fluid?

Sounds like a dead CP3. Chevy never ran a lift pump on the D-maxes, instead they relied on the CP3 to suck fuel from the tank. With all the crap that went through it, it probably scared the gears that produce the high pressure.

Bad CP3?
 

Hello,
I have not gotten it to run. I have taken all WVO stuff off. I am going to bring it back to the dealership unless something miraculous happens. How do I know if it's the CP3? How much will that cost to replace?

Thanks,
Chris

What did ya get figured out??

I got nothing. I dropped it off at the dealership yesterday.
Chris

CP3's are CRAZY money at the dealership and its like a 6-8 hour job so labor is not likely to be cheap either.

For Reference a CP3 on line (new) is less than $800. OUCH I know, but wait till the dealer tells you what they want. LOL.

dealsership thinks its the fuel filter housing. Bought one online for 269 plus 400 core deposit for the broken stock one... I';ll let you know if it gets going well again.

new purchase: 94 cummins 5 speed, 4x4, reg cab long bed.

looking for 94-98 ext cab 4x4 5 speed 12 Valve 2500.

for sale: 03 Dmax....