Dodge Cummins Diesel Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
175 Posts
Discussion Starter · #1 ·
Hey guys.. I tried to do some searching online and the answers are all over the place or the threads quickly get off subject. Sorry if this has been discussed many times before but hopefully I can get a concise, quick answer!

My 03 has 245k on it. About 5 years ago (when I lived in AZ) i took the grid heater out (and threw it away - dooh!). But my truck has always started easy even in sub zero, not plugged in!

Well up until the last 12 months. It has slowly gotten harder to start as the weather gets colder. Well yesterday when I started it in the garage (which was about 25 deg) it cranked for 5 seconds. I backed it out, shutted it off, and it sat until evening. It was about 10 deg outside.

I couldn't get it to fire. I plugged it in for 2-3 hours, put a charger/booster on it. It would crank quickly but would not fire.

I finally resorted to a quick puff of ether in the intake (remember, no grid heater). It fired right up and ran fine.

During this whole time, my fuel economy has remained constant at a good 18-20 mpg. Injector noise/rattle has been no worse/better. Smoke is non-existent. It's just getting harder to start.

My philosophy is that the truck is having a hard time building pressure because of worn injectors (hey - 245k!). This seems to be what most others are experiencing.

However, how do I know it's not something else? Like the CP3? FCA? How can I eliminate those? The only gages I have (right now) is EGT and trans.

I am not against pulling the injectors and having them tested, I suppose. But I don't want to waste my time and money if it's something else.

Also, what/where is a good place to buy "new" injectors? I'm thinking with my stockish truck and my intentions of never being crazy that stock injectors are the best choice.. perhaps 50hp injectors at most. I have UDC so I have some leverage on duration, timing, etc..

When others have done this job, do they buy or rent the tube and injector pulling tools? Again, I'd hate to buy this stuff for one change out.

Thanks!
 

·
Registered
Joined
·
2,404 Posts
Sounds like you need to check the rail pressure with a gauge, the ECM looks for a minimum pressure before it activates the FCA. I think it is around 4000 PSIK, Injectors usually start smoking white on start when they start leaking or by-passing fuel and mileage drops off. Lift pumps on the early Common rails are notoriously weak so I would start by checking supply pressure. That's assuming you have done the maintenance on your fuel system like changing out the filter and draining the water separator.
 

·
Premium Member
Joined
·
7,069 Posts
These threads often get off track because the no start has so many causes and were not there.

You mentioned crank speed sort of. Does it crank fast like normal for the temp?
Batteries, cables and or starter.

When you turn the key on does the lift pump run?
Open the drain with a hose on it into a clear bottle and bump the starter with the key. Fuel should come gushing out. Check for water and change filter while empty.

Now you have mainly the CP3, FCA, Rail pressure relief valve, and injectors.

Remove the banjo from the RPRV and move the hard pipe out of the way with a bag over it to catch fuel. Dry out the valve in the rail.
Start the engine or crank it. NO fuel should come from the valve.

I would always re-torque the injector tubes to 41ft/lbs before pulling the injectors, They come loose causing low RP when they leak.

You can disconnect the FCA and try to start it if the valve is good but that only says low RP if it does start.

A CP3 is not easy to user test and FCA's have NO definitive test. You can replace it with one from Genos garage if it did start disconnected.

Knowing RP helps but in reality 90% of the time with injectors over 140,000 miles they are the cause.

Send off for testing or just replace them with new from EXERGY, DAP, BBI for stock new. It's almost guaranteed an injector or 6 are going to fail when tested properly.

BOSCH Motorsports are NEW and the 3 above are some of the very few that can get stock new injectors on limited supply.
With exergy they can make old injectors as good as new and tested properly and balanced probably better than new.

EDIT A bypassing high return injector will lower the RP and cause a no start but usually not cause white smoke.
A leaker nozzle will lower RP causing the no start and become a piston melting blow torch when running and probably white or black smoke and even make the engine run away.
 

·
Registered
Joined
·
175 Posts
Discussion Starter · #4 ·
Yeah, sorry forgot some of those items.

On maintenance, every oil change I switch out the fuel filter. I just use the Fleetguard premium (which I think is 3 or 5 micron). I use Howe's every fill-up. I have a Walbro pump which delivers a constant 15psi at idle (and during cranking for that matter). So I believe fuel delivery is not an issue.

I know, I would think that if the injectors are wearing out you would see more symptoms like rough idle, smoke, etc..

Any idea how I can see rail pressure during cranking? All I've got to work with is the Smarty.. and EGT and Trans. I should of got an CS or CTS monitor, but I'm not sure either one of those would see rail during cranking either.

Also, oil quantity seems good, no apparent fuel in it and the color is decent even after 10k miles between changes.

Thanks for the help!
 

·
Premium Member
Joined
·
7,069 Posts
You already proved you have low RP as long as it cranks fast because it starts with either.
You won't see rough idle on a high return injector most times. It could be all of them together.
 

·
Registered
Joined
·
175 Posts
Discussion Starter · #6 ·
Thanks waywardtravel.. I didn't see your post prior to my second post. Must of been typing at the same time.
I agree, I should probably re-torque some of the fittings. The area around the fittings is a little oily/greasy and perhaps they are leaking ever so slightly.
Obviously I already answered the question about the lift pump, so I think I am ok there.

Batteries are near new and crank speed was adequate IMO. Obviously putting a booster on it in the cold weather helped it crank a little faster but didn't help.

So I will torque the fittings down and do the rail valve test. After that, if this issue comes back, should I disconnect the FCA when I attempt start? If it does start, what does this tell me? That I indeed am not building enough pressure? I agree that swapping out the FCA is probably a relatively inexpensive trial and wouldn't hurt.

When it does start without the FCA is it going to do full rail pressure?

Thanks!
 

·
Premium Member
Joined
·
7,069 Posts
You can buy a rail cap and cap injectors and start one at a time measauring returns into a graduated cylinder but it's usually a waste of time
 

·
Premium Member
Joined
·
7,069 Posts
Yes a disconnected FCA will command max rail and the truck will idle like crap.
Don't rev it just shut it down then replace the FCA on the long shot.
 

·
Premium Member
Joined
·
7,069 Posts
wetness only around the injector tube nuts IS a sign they are leaking. The bulk of the leak if not all just returns through the return galley. If it's wet then the o-ring is ALSO leaking.
 

·
Registered
Joined
·
175 Posts
Discussion Starter · #10 ·
Ok thanks.. I've got a little work to do.

For what it's worth the only odd thing I've noticed more lately is that during high idle (with or without the Smarty tuning..) the truck idle is lumpy. I know some programmers can make this worse but even with "stock tuning" it is sometimes lumpy. I'm wondering if I should just switch out the FCA for $100 to eliminate that possibility.

So to start I think I should:
New filter, drain canister to make sure no water, etc.. is in there.
Tighten the injector fittings (I saw 37 ft-lbs).
Replace FCA.

Agree?
 

·
Premium Member
Joined
·
7,069 Posts
Ok thanks.. I've got a little work to do.

For what it's worth the only odd thing I've noticed more lately is that during high idle (with or without the Smarty tuning..) the truck idle is lumpy. I know some programmers can make this worse but even with "stock tuning" it is sometimes lumpy. I'm wondering if I should just switch out the FCA for $100 to eliminate that possibility.

So to start I think I should:
New filter, drain canister to make sure no water, etc.. is in there.
Tighten the injector fittings (I saw 37 ft-lbs).
Replace FCA.

Agree?
NO I would do it like I said above on any truck usually in that order.
Don't forget the RPRV.
The old style tubes spec was 37 ft/lbs and the new style is 41 ft/lbs.
They are a crush seal tapered fit. That's why I ALWAYS go to 41/ft/lbs on a re-torque and ALWAYS replace tubes with injectors.
 
1 - 11 of 11 Posts
Top