I have an injector question

[thechevyhdman]

Ok remember something a while back about the Ford cackle, A cackle noise caused by low pressures of fuel brought to the furthest cylinders from the Inj. Pump? My question is on saturday I took my predator to a few different trucks, And noticed that Cylinder 1 flow rates were off on every truck...to the tune of -2.0 or more....I assume that means more flow then say -1.5? Could it be that some injectors are off from the close proximity of the Inj pump, Or are they just plain off, because shouldnt common rail have equal pressure to all injectors...or am I just smoking crack. Just wondering Bill

[GM Smitty]

My #1 is also the worst of all of them. I think I remember Kennedy saying that #1 is usually a bugger. I know I didn't answer your question..but that's because I don't know the answer. tongue.gif
Josh

[Gbenzx01]

Well chevyhdman,
Sorry to hear this, indeed if we have a furd cackle in our Dmax anywhere besides in the cab of the truck we're in a mel of a hess! tongue.gif
Sorry I cannot answer your ques but do wish someone would sense ours has the little, don't laugh, che, che, che sound at the exhaust.
It has had this since day 1 & ser mgr says, you guessed it, they all do that.
Up to the Penton & Phenix City Al races this weekend with Paul George & his new Dmax3500 pulling the big 3axle. And guess what, che, che!
Not as pronounced as ours but he still has the muffler. Maybe more guys will see your ques this time around & thnx for sharing your results.

Gben

[hoot]

You all know I hate to bring this up but might as well cause it's common knowledge....

Broker has four..... count them.... four Duramaxes, one was sold with 468,000 miles on it. He has an 04 on order. He puts literally hundreds of thousands of miles on his trucks a year and has no injector problems.

I believe he runs secondary fuel filtration but that's about it.

I think we don't have a thing to worry about. These issues are surely few and far between as long as we keep our fuel clean and don't do the mods.

[56Nomad]

Hoot,

I thought that all of Broker's claims were bogus
and without any merit :confused:

[Amianthus]

What you describe would stand to reason on the HPCR system. My guess as to why the #1 is tricky, has to do with the firing order of the engine and it's proximity to the pump. The firing order causes pulses in the rail system. If you stack a couple of these pulses close enough together, you can create a low pressure condition in the rail (temporarily). Running at higher RPM, the pump has sufficient capacity to counteract the effect of the pulse overlap in the rail and the problem all but disappears. This wouldn't be a problem in an all laminar flow system, but such a system will never exist (currently impossible). It's either that or the pulses from the injection pump (because of the location of the injector relative to the pump) are beating up on the injector enough to cause it to go out of balance. (Note-This is just my guess. Pure speculation on my part and I could be way off here.)
I really wouldn't worry about it too much. Unless the cylinder becomes grossly imbalanced. I mean, how often do you idle down the highway. I certainly don't.

[Lone Eagle]

What is a laminar flow system? Later! Lone Eagle

[mackin]

My assumption was idling was giving you a "clue" of injector performance ??? Compensating if you will to keep a smooth consistent idle at 630 approx. rpm .....

If the balance rate,pulse rate, is out, a bad injector is apparent, no ??

Mac http://forums.thedieselstop.com/ubbthreads/images/graemlins/shrug.gif

[Amianthus]

Laminar flow is a theoretical ideal of fluid flow through a system. With any fluid system you are bound to get turbulence. In a pure laminar system, turbulence doesn't happen at all, therefore there is no restriction to flow from turbulence. An example would be to turn on your garden hose to a low flow and observe the quality of the stream as it exits the hose. It should be pretty clear and flow out smoothly. This is pretty close to laminar flow. Then turn it up to full-bore. Notice that the stream leaves more violently (if you have the pressure ability to do this). This is because you do not have laminar flow. This same type of problem occurs in any fluid system. Does that make sense?

mackin, I would agree with you that those indications would lead one to show a failing injector. However, being that number one seems to be the most problematic, I am thinking that there are other forces at work other than just a bad injectors. Rail pulses will have an effect on injector performance for sure. I believe that is what contirbutes to the difficulties with balancing the system. These pulses would be hardly noticable at higher RPM as the pump would be able to overcome low pressure spikes in the rail because it's capacity would be higher. At least in regards to number one injector.
Balancing them at idle will certainly make it run smoother at RPM, but I don't think it's as critical for normal operation. It will cecrtainly deviate from balanced at idle to balanced at RPM.
Take this with a block of salt. I have limited experience with the Dmax's HPCR system. So I could be way off base here. This is just speculation on my part based on what little I know.

[hoot]

I hope you're not comparing HPCR with the Navistar HEUI setup when talking about pulsing. Remember, the PSD injector is driven by high pressure engine oil as a hydraulic medium. This has proved to be an inconsistant medium with respect to injector timing precision. Between that and the poorly designed integral fuel rail "laminar flow" the chances of pulse effects is much greater.

The Dmax uses a three piston radial high pressure fuel pump with a low cam profile. This helps keep pressures off the driven mechanicals and reduces pulsing from the pump.

The only pulsing you get is the injectors firing which is only a very small solenoid activated event in a pretty large and highly pressurized rail. I'm not so sure of the significance of it.

Maybe something else is effecting that particular cylinder? Air intake due to flow anomalies in the intake system. Not unheard of and that could effect the power stroke..... which is what really is being measured for "balance" is it not? You can't assume it's the injector right off the bat because balance is off, am I correct?

[Amianthus]

Perish the thought, hoot! I wasn't trying to compare them directly, although I think I accomplished that. My purpose was only to point at it and say (laugh) that fuel line pressures drop out on the HEUI because of firing order and pump flows. It stands to reason that firing order and rail pressure harmonics could impact the balancing of the HPCR injectors. Just my thoughts.

I don't know if the pulsing is causing the problem or not. And probably won't know unless extensive flow testing is performed on the rail under several operating conditions. I'm just speculating. Pulse harmonics in the rail would be hard to investigate for sure. Like I said, unless it grossly out of balance, I really wouldn't worry about it too much. I'm sure that if we were to put a truck on a dyno at steady state, the balancing flow rates would be much closer. (Do you want to volunteer your truck for testing on our new dyno? It would be fun if nothing else.)

You're right. It could be air flow issues also. But I think it would be a fuel system issue more than air flow.

Either way, solutions to fixing it would be difficult at best. Although, I don't think the impact would justify the cost.

Kennedy? DmaxAllitech? Your thoughts? Am I way off base here?

[Gbenzx01]

Is this what is causing the problem noise I'm hearing?
And right pretty obvious what GM is upto. In 04 it is said that the valve covers will be redesigned for easier access to injectors. I doubt this will sell more trucks but it may lesson the warantee labor bill they get from the dealers! I would gander(hope I'm wrong, again) that they have selected the least cost route in this instance to the problem. First indicator tome anyway was, yes I guess it'll be ok to use a demulsifier. Here again, most of us here on DP anyway have known for some time what the oem filter is. Is water&/or steam if you will doing something it ain't possed to? Electronics?
No I don't like to think such but when some of the best talent that can be had start doing strange things I just naturally seek the causes.
Don't you? Even a very minor change in mass assembly today becomes a costly item to say the least.
Yes, I know MP had to change the ISP cause I used too much real estate. :rolleyes:

Thanx, Gben

[dmaxalliTech]

Hoot gets two points for correctly defining the HP pump setup, but looses them right back for the refernce to Brokers :D

As far as pulses, the pump, as mentioned, is designed to not have a pulse to it. The rails act as accumulators thus absorbing any slight pulse that is there. I must admit, I have not noticed that no 1 is a predominant cylinder as far as balance rates etc are concerned. I will check this theory out on the next few trucks I see.

I dont believe that balance rates at the 2.0 mark are anything to worry about + or -. Gm allows up to 4.0 +and -.

Hoot:

I think we don't have a thing to worry about. These issues are surely few and far between as long as we keep our fuel clean and don't do the mods Your correct on this, even with mods I think we are ok... But, I have put in 14, yes 14 injectors this week alone :eek: :eek:


Gben:

In 04 it is said that the valve covers will be redesigned for easier access to injectors. I doubt this will sell more trucks but it may lesson the warantee labor bill they get from the dealers! I would gander(hope I'm wrong, again) that they have selected the least cost route in this instance to the problem. First indicator tome anyway was, yes I guess it'll be ok to use a demulsifier. Here again, most of us here on DP anyway have known for some time what the oem filter is. Is water&/or steam if you will doing something it ain't possed to? Electronics?
No I don't like to think such but when some of the best talent that can be had start doing strange things I just naturally seek the causes.
Don't you? Even a very minor change in mass assembly today becomes a costly item to say the least.
You are correct on the redesign. I am not sure if easier access to injectors is the prime reason though. I think that there are multiple reasons for change. One being the introduction of more smog crap, The return system will be external to take away the possibility of fuel contamination in the oil from return system leaks, Common. The plumbing will also undergo some changes, reducing the number of connections, simplify routing and again, to make room for emmisions. The cyl head, rocker cover, intake, turbo, will all be changed. The jury is out as far as if these changes are good or bad, We will have to wait and see for sure. We do have some 04 trucks on the lot, but no Diesels as of yet, the only changes I have seen are cosmetic on the gassers. They have a Denali style projection headlamp. Thats the only thing I have noticed so far.

[mackin]

My only thought is I want NEW injectors ..... Looking at recent balance rate, indicating high-3 and low-4 is that a whole lot of fuel is ATTEMPTING to be pulled away to idle out, just imagine WOT ..... Really would luv to have injectors replaced prior to a catastrophic issue .... This motor is sound, uses NO oil, and was broken in properly, I don't want to lose her .....

Cat filter 2 micron absolute in the works, to little to late for this set.....

Mac :(

[dmaxalliTech]

Originally posted by mackin:
My only thought is I want NEW injectors .....
Mac :( Aint gonna happen, no such thing anymore. All replacements that we are getting are reman only. Cant get new, tried today and no happin. (sorry JK)

[Lone Eagle]

Is there a price break on the re-manufactured injectors? Later! Lone Eagle

[dmaxalliTech]

Originally posted by Lone Eagle:
Is there a price break on the re-manufactured injectors? Later! Lone Eagle Nope, same price, same part no... expect to pay 325 range..have seen them cheaper though

[jbplock]

Originally posted by dmaxalliTech:
...All replacements that we are getting are reman only. Cant get new, tried today and no happin...Could this imply that 01-03 injectors are no longer in production and the new 04 injectors are different? I guess it could also imply that there is an abundance of remans available from warranty returns... Just curious...

[DMax_Doug]

To balance out what have otherwise been technically informative and insightful posts on injectors, please let me demonstrate my complete lack of knowledge on this topic.

I've been monitoring with my Predator the balancing rates on my Dmax, which is at now 46k/miles. I'm seeing the same as noted above, with No 1 at about -3, the rest right around 0-1 +/-. I've changed my EOM fuel filter 3 times now, and am contemplating installing a secondary filter also.

My question is, can our injectors be serviced before they fail outright? I hear about injector "services" for other types of fuel-injected vehicles, and wonder of such a service is possible on the Dmax and would it make sense as a preventative measure.

Doug

[dmaxalliTech]

DMAX DOUG...its called fuel additive with lubricity :D

[DieselDavy]

DMaxalliTech,
You said the '04s will have rerouted return lines along with a lot of other changes in the area. I think I read where you thought the injectors are being removed from (underneath) the valve cover altogether. Is that still the case? Seems to me, cost of R/R of fuel injectors would be a fraction of what they are now. Any updates?
Thanks for your service to our fraternity! tongue.gif (Diesaholics)
Dave

[imported_]

While I was up at Nick's (ndamico) getting my 2 micron CAT installed, Nick checked my injector balance with the Predator. One was in the 3's, one was around 2.5 while the others were in the 1's. They all flattened out to .82 at high idle.

Are these higher numbers on the 2 injectors at idle cause for much concern?

I've been using Primrose 405. Is there anything else I could use to clean them out?
Alternatively, is there a way to adjust them?

BTW, still no problems whatsoever with the large CAT 2 micron filter mounted pre-OEM using Nicks bracket up in the wheel well by the filler tube. That's after about 550 miles hwy cruising last weekend and about 100 miles stop and go around town over this past week.

No hesitiation. Just as quick starting and as smooth running as always.

[dmaxalliTech]

Originally posted by DieselDavy:
DMaxalliTech,
You said the '04s will have rerouted return lines along with a lot of other changes in the area. I think I read where you thought the injectors are being removed from (underneath) the valve cover altogether. Is that still the case? Seems to me, cost of R/R of fuel injectors would be a fraction of what they are now. Any updates?
Thanks for your service to our fraternity! tongue.gif (Diesaholics)
Dave yes, they will be external

HB:

Are these higher numbers on the 2 injectors at idle cause for much concern?

Not really, once they get above 4.0, then keeep an eye on them

[imported_]

D/A Tech,

Thanks!