rhader

Hey Guys,

So I just picked up a new to me 03 Cummins - in absolutely amazing shape - but of course lo and behold but either something funky with the injectors or something with the Lift Pump....

if I leave the key in the 'on' position for a few more seconds after the 'heater' Light goes out - and then crank it over it seems to start better - but still takes a few cranks longer than I would expect...

also I was driving through town and it stalled on me in a parking lot just quite - scared me a little as I was afraid it wasnt going to start.... the first crank over - it didnt - I stopped backed the key off turned it to on and left it there for a couple of seconds and then cranked it over again and it cranked a little longer than it should but fired up alright and then seemed to run fine...

is that an indication of fuel pressure?

it also seemed a little 'clackier' for lack of better description - the sound seemed to go away after a little while - though I hope this isnt an indication the the IP is damaged?

doesnt seem to be any smoke - and when its running still lots of power...

still seems to have plenty of power and im getting an average of 28mpg... city driving. (according to the overhead gauge of course....)

I picked up a BD max flow lift pump:

BD Power - Product: Flow-MaX Lift Pump


it has a 5 year full warranty on it - so hopefully that will do the trick - I have yet to install it - but will keep you posted!

from looking into it a little further and listening to the actual Injection Pump

- I am guessing that the Injection pump is actual creating the pressure and this results in the linger time to crank / start... and that the 'lift pump' is essentially doing F-all.... and in turn causing the IP to work harder...? does that make sense?

I have heard that the Duramax uses the same 'CP3' pump without a LP and does not get damaged at all... ??

also I noticed underneath the current OEM - LP in the truck that there is a what appears to be another filter - is this what would be considered a 'pre-filter'?

And a couple of questions for installation of the new aftermarket BD Lift Pump...

1) if I splice into the metal fuel line and use rubber fuel lines - do I need any specific connections for the pressure?? or will a couple of hose clamps hold the 15 - 18psi? i.e. do I have to flare the splice tube at all?

2) can I leave the existing OEM LP in place?? and simply run the feed from the new aftermarket LP into the oem LP??

3)the voltage to drive this new LP - can i pull the 12V plug from the OEM and essentially just extend it to plug into the new aftermarket LP?

I am assuming that the 12V feed to the LP is an ignition type 12V feed and I should really use the same type of setup electrically.... Also this is assuming that the oem LP does not have a fuel shut off internal when voltage removed and maintains a 'thru passage' free of obstruction to feed thru?

I am thinking that I should put this LP in anyway as the OEM ones are known to fail... is this a good course to follow? and then of course put a fuel pressure gauge on it to follow this from now on?

and perhaps one of the injectors is bleeding off when the truck is shut off?? can I clean the injectors to correct this??


any help appreciated!

FMB

Welcome to DTR and sounds like you have chosen a great truck. Go to the Grey bar up above and click on "User CP". Fill in your "Signature" so we all know what you have each time you are here. (really helps)

I'll try to answer your questions in order... You didn't mention how many miles on the truck, but being an '03, the injectors are probably getting tired and leaking by. This makes it more difficult to pressure up for easy starts. You may look into F1 for testing, new tips and rebuild.

I'm not sure why your CTD quit in the parking lot. Do you know how to pull the codes?

You must be real happy to be getting 28 MPG with city driving. You will be disappointed, however, when you do the math yourself (miles driven divided by fuel bought to fill the tank). Sorry to burst the bubble, but the semi-official name of the overhead display is Lie-O-Meter.

The original Lift Pump is mounted on the back of the fuel filter canister. When this goes bad, it hinders or stops fuel flow to the CP3 and the CP3 cooks itself to death. I see you will be installing a new after market LP,but the old one needs to come off and the hole blanked. All the pieces/parts may be in the kit you are getting. If not, they are on the market. Are you adding a Fuel Pressure Gauge?

I have an after market LP with rubber lines connected to the steel lines with a hose clamp. It's only lasted 150k miles or so with no leakage, so I think its ok, especially since a trip to Inuvik, NT. (458 miles of gravel highway each way of the last leg)

Voltage for your new LP should come from the old LP's connector. It is powered through the computer and not just a straight shot from the battery.
Happy Easter, and back to morning brew. . .

rhader

thx for the response! I have posted in response in the 'blue' below...

thx again.

FMB

Call one of the F1 dealers, they will know more about rebuilding than I. Sorry.

There can be codes without setting the engine light. Try your scan tool, or without starting the engine, turn the key on, off, on, off, on. The codes will show up in the odometer... have your pencil ready.

The fuel from your new LP cannot go through the old LP. It is way too restrictive and may even close. Not good for your CP3. Call this guy. He is very helpful and if he doesn't have the part that goes from your LP fuel output hose to the fuel filter, he'll point you in the right direction.

rhader

ok - thx.

currently there is no smoke on startup. not black not white either... starts up pretty consistently at a 2.5 second counter... i.e. count 1... count 2... count half... and running.... dont give it in any juice or anything... on a few 'hot' starts it definitely takes a little bit longer the odd time....
I am wondering if maybe a programmer could cause this?

there is the BANKS exhaust on the thing and it is a possibility that a programmer was installed somewhere and I just havent found it yet...