[Grumpy_one]

My 2003 5.9 is completely stock, has 94k miles, I've had it since new. It's starting to get hard starts, the worst one yesterday, took about a half minute of total cranking to get it started (3 attempts, no more than 10 seconds each time) finally started. I'm being told it needs new injectors. If it is injectors, I might as well start upgraded and unleash the hounds. I tow a 23 foot fishing boat about 6k lbs regularly. The tranny has a billet torque converter. That's the only upgrade so far. Want to keep it mild, but some upgrade to some extent and I know the sky is the limit with these things. Do I upgrade pump while I'm doing the injectors? Turbo? Jake brake? Don't want to get too crazy. Look for some thoughts. Thanks

 

[rghavana]

Try plug in block heater ? if starts easier then usually injectors
IMO
Smarty Touch for gauges/tuning/diagnostics
BBI injectors/new tubes
upgraded fuel filtering
if needed 05+ fuel pump ,
exhaust brake if towing regularly

 

[Cartwheels]

Agree with what's said above. Could check crossover tubes for correct torque and check rail PRV for leaking before dropping new injectors in.

Probably don't need larger injectors (unless you have big plans) just a good 50hp tunes will wake your truck up. Larger injectors will net you higher egt unless u install a larger turbo.

Imo now would be a good time to address the fuel filtration issue these trucks have. My choice would be one of these kits, 03-12 Cummins Fuel Filter Kit

 

[Grumpy_one]

I don't have big plans, but stock injectors and a 50hp tuner is what my mechanic is recommending as well. I'll look into doing a leak check on the rail and checking torque on the crossover tubes in the meantime. Thanks

 

[Cartwheels]

I would definitely recommend BBI injectors if everything confirms they are bad.

 

[Txwelder]

I agree on the BBI injectors. See the mods to my 03 in my signature and I am VERY pleased with it towing and unloaded. If you are doing injectors I recommend you do head studs, valve springs and pushrods while you are there. I started with a turbo, then #4 injector went bad so then I did BBI 0.5's. Then I wasn't happy with EGT's when towing heavy and was having overheating issues so I studied on compounds and supporting mods as well as aluminum radiator and upgraded trans cooler. It is a vicious cycle that will eventually get the best of you no matter what you tell yourself. Good luck!

 

[hpitt74985_1181]

Same thing happen to me. I plugged in my block heater for ten minutes. And truck started. This was in 30 degree weather. I put new stock injectors in. Truck is stock.
Howard

 

[jkidd]

Check cheap things first. 94k is still fairly low mileage for a 2003 injectors- they often last a lot longer 160k is common. The 2005-07 injecotrs have an extra injection event and wear faster.

Are your batteries strong?
Is your grid heater working?
Do you have lift pump pressure/supply to the CP3?
Have you unplugged the FCA and tried cranking?

If you want 500-550HP then a smarty and some 50HP injectors will work fine once you add a 62mm s300 turbo. Transmission will be next.

 

[hpitt74985_1181]

I will keep my truck stock. It has been very reliable. I finally replaced my injectors at 234,000. I have a early 2003 ca so 5.9. I am not going to do any mods to the 5.9 right now because then the 47re will need upgrades. I own a 37ft 5th wheeler and a 28ft bumper pull. As long as have common sense used on towing and knowing the combined weight of truck and trailer then you won't have overload break downs.
Howard

 

[Grumpy_one]

The hard start seems to have been a one time event. The injectors will come out and be tested. JKIDD, thanks for the offer, I have a shop that's doing the work. Cartwheels, I'll look into that filter, thanks.
Are your batteries strong?
Yes
Is your grid heater working?
wouldn't know if it wasn't. will look into symptoms
Do you have lift pump pressure/supply to the CP3?
see above
Have you unplugged the FCA and tried cranking?
no

Since retiring, I've left the wrenching to a trusted shop. I still have two rollaway's full of tools, but I spend my spare time fishing now and making fishing vids for youtube, I have a channel. The mechanic who is doing the work has a 04 just like mine and has done similar work to his. He went with 50 hp injectors and went back to stock due high EGT's. I will probably do same, keep the injectors stock and not go down that rabbit hole. The truck has done fine towing the boat the last 6 years with no issue. I might get a tuner. Looking into smarty or edge, I'll ask my mechanic and see what he recommends. In the meantime, I will follow up with above questions. Thanks for all the feedback. Really helps.

 

[GoldCountryCA]

dang it, +50hp injectors increase EGTs? no one mentioned I needed to upgrade my turbo when everyone was recommending the +50hp injectors. my primary reason for getting them was tuning for efficiency with the SAC nozzles. now I'm a bit concerned with the choice...

 

[Cartwheels]

Agree with what's said above. Could check crossover tubes for correct torque and check rail PRV for leaking before dropping new injectors in.

Probably don't need larger injectors (unless you have big plans) just a good 50hp tunes will wake your truck up. Larger injectors will net you higher egt unless u install a larger turbo.

Imo now would be a good time to address the fuel filtration issue these trucks have. My choice would be one of these kits, 03-12 Cummins Fuel Filter Kit

I thought this is what I was trying to say in this post.